Hierarchical time synchronization method, apparatus and system for multi-source wide-area power distribution and utilization network, and chip

Abstract

The present application relates to the technical field of power distribution and utilization and communications, and specifically relates to a hierarchical time synchronization method, apparatus and system for a multi-source wide-area power distribution and utilization network, and a chip. The present application proposes the concept of a multi-source fusion node. The multi-source fusion node can support and fuse time information from a plurality of different timing sources, and perform time synchronization on a designated node on the basis of a fused timing reference. When acquiring the fused timing reference, a first intermediate value set is determined first on the basis of a plurality of timing references. When there are a plurality of first intermediate value sets, a plurality of second intermediate values are further calculated on the basis of the credibility of the timing sources or the deviation between the timing references, and an optimal second intermediate value is selected as a time synchronization reference by means of a preset rule. When time synchronization of the designated node is completed, hierarchical time synchronization is performed on other nodes on the basis of the time-synchronized node. Thus, the precision and efficiency of time synchronization in the multi-source wide-area power distribution and utilization network are improved, ensuring the time accuracy and synchronism of wide-area power distribution and utilization services.

Description

Hierarchical time synchronization method, device, system and chip for multi-source wide-area power distribution networks

[0001] Cross-reference to related applications

[0002] This application is based on and claims priority to Chinese Patent Application No. 202411620083.4, filed on November 13, 2024, entitled “Hierarchical Time Synchronization Method, Apparatus, System and Chip for Multi-Source Wide Area Power Distribution Network”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the fields of power distribution and communication technology, specifically to a hierarchical time synchronization method, device, system, and chip for multi-source wide-area power distribution networks. Background Technology

[0004] The power system is a critical infrastructure, vital to national economy and security. Given its geographically dispersed nature, achieving continuous monitoring of grid operation, rapid fault identification and location, and timely response and repair requires readily available standard time across a large scale to maintain time synchronization within the power system.

[0005] The efficient interaction and safe, stable operation of power distribution and consumption rely heavily on various automatic monitoring devices, and providing a unified time reference for these devices ensures the validity of measurement data. Strict time synchronization is required in operations such as synchronous data collection, differential protection, fault monitoring and handling, and time-of-use billing. Time calibration and synchronization are the core foundation for achieving efficient data acquisition, intelligent control, fault early warning, and remote management. Nodes within the power distribution network not only need to accurately record electricity consumption information but also need to collaborate based on a unified time reference to ensure the accuracy and real-time nature of data analysis.

[0006] Time synchronization of power distribution network equipment generally includes two stages: the first stage is time synchronization of the power distribution terminal, where the power distribution terminal obtains a precise time reference through clock sources such as satellites and networks; the second stage is time synchronization of the distribution area, where the power distribution terminal broadcasts the time to meters, switches and other equipment in the distribution area through the local communication network, thereby achieving the goal of accurate clock synchronization of power distribution network equipment throughout the area.

[0007] For power distribution terminal time synchronization:

[0008] High-precision and reliable time synchronization sources are the foundation and guarantee for time synchronization in power distribution terminals. Currently, the commonly used time synchronization methods in power systems mainly include: satellite time synchronization (such as BeiDou, Global Positioning System (GPS), and low-orbit satellite time synchronization), terrestrial network time synchronization (such as Network Time Protocol (NTP) and Precision Time Protocol (PTP)), radio wave time synchronization (such as longwave time synchronization and shortwave time synchronization), and 5G communication technology time synchronization.

[0009] Among them, space-based time synchronization based on navigation and positioning satellite systems such as Beidou and GPS has high accuracy and is not limited by geographical location, but it has problems such as lack of indoor coverage, obstruction in dense urban areas, and high maintenance costs; terrestrial network time synchronization mainly uses Ethernet, cellular networks, etc. for broadcast time synchronization, which is easily affected by network latency and error accumulation; radio wave time synchronization has a long propagation distance and can cover a large area, but compared with satellite time synchronization, the time synchronization accuracy is lower and it is easily affected by weather conditions (such as ionospheric disturbances) and electromagnetic interference; 5G communication time synchronization has the unique high reliability and ultra-low latency characteristics, making it an ideal way for power time synchronization and transmission, and providing the possibility for the construction of high-precision time networks. The time synchronization error between 5G base stations in my country is within 1.5μs, but when using 5G air interface technology to synchronize the time of power distribution terminals, there are time synchronization accuracy errors caused by time division duplex communication, inconsistent uplink and downlink rates, and latency asymmetry. At the same time, 5G air interface wireless transmission may be affected by factors such as signal-to-noise ratio, transmission bandwidth, and base station-side processing, resulting in large air interface latency jitter, which in turn affects the time synchronization accuracy. Under normal circumstances, the time synchronization accuracy of power distribution terminals using 5G air interface technology is about ±100ms, which cannot meet the high-precision clock requirements of power distribution services.

[0010] Therefore, it can be seen that the existing single time synchronization method has its own shortcomings, and its wide availability and adaptability are difficult to meet the high-precision time synchronization needs of a large number of power distribution and consumption terminals.

[0011] For the school hours in the Taiwan area:

[0012] In terms of time calibration and synchronization between the distribution terminal and metering equipment nodes, power lines are the most ubiquitous and widely covered physical medium. Using power lines to transmit data offers great convenience, eliminating the need for rewiring and allowing all appliances connected to the power line to form a communication network for information exchange and communication. Therefore, using power lines as a communication medium for time calibration has become an economical and efficient solution.

[0013] Currently, the published high-speed power line carrier and high-speed dual-mode communication protocols stipulate that all nodes within a distribution area support time synchronization of electricity meters by terminals. During time synchronization, a specific device (e.g., the Central Coordinator (CCO)) can be selected as the master node, and its clock is set as the base time. Other devices (e.g., the Proxy Coordinator (PCO) and stations (STAs)) act as slave nodes. The master node periodically or as needed broadcasts time synchronization information (such as timestamps, time signals, etc.) to the slave nodes. The slave nodes receive the time synchronization information and adjust their own clocks accordingly to achieve time synchronization with the master node.

[0014] Although power line carrier technology is favored due to its high adoption rate and wide coverage, it still faces many challenges in practical applications. First, power line carrier signals are susceptible to electromagnetic interference during transmission, such as changes in power load, line aging, and harmonic interference. These factors can lead to signal attenuation and distortion, thus affecting communication quality and time synchronization accuracy. Second, due to the large area of ​​the distribution network, when slave nodes synchronize their time based on the master node's time information, the synchronization signal needs to be forwarded through multiple relay nodes during transmission. This not only increases communication latency but may also lead to a significant increase in time synchronization deviation at the terminal nodes due to the accumulation of errors at each relay stage.

[0015] Improving the accuracy, synchronization, and reliability of time synchronization in power distribution networks, thereby enhancing the overall reliability and stability of the power distribution network, is an urgent problem to be solved. Summary of the Invention

[0016] To address the problems in related technologies, embodiments of this application provide a hierarchical time synchronization method, apparatus, system, and chip for multi-source wide-area power distribution networks.

[0017] In a first aspect, embodiments of this application provide a hierarchical time synchronization method for a multi-source wide-area power distribution network. The power distribution network includes multiple nodes, at least one of which is a multi-source fusion node, supporting fusion time synchronization from multiple different time sources. The power distribution network also includes end-user wireless devices connected to nodes in the power distribution network. The time synchronization method includes:

[0018] The time synchronization of designated nodes in the power distribution network is performed through the multi-source fusion node in the following manner, wherein the designated nodes include the multi-source fusion node or nodes other than the multi-source fusion node:

[0019] Obtain multiple time signals from multiple different time signal sources;

[0020] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0021] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple second intermediate values ​​are determined based on these sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to that set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to that set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0022] When there is only one first intermediate value set, the elements in the first intermediate value set can be one or more, and the specified node is synchronized according to the first intermediate value set;

[0023] After the designated node completes the time synchronization, the other nodes in the power distribution network are synchronized based on the designated node.

[0024] After the nodes in the power distribution network complete time synchronization, the time synchronization period of the terminal wireless devices is obtained based on the time error coefficient and the maximum time synchronization tolerance threshold of the terminal wireless devices connected to the nodes; the time synchronization of the terminal wireless devices is performed according to the time synchronization period.

[0025] Secondly, this application provides a time synchronization method for a multi-source fusion node, wherein the multi-source fusion node supports fusion time synchronization from multiple different time sources, and the time synchronization method includes:

[0026] Obtain multiple time signals from multiple different time signal sources;

[0027] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0028] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple second intermediate values ​​are determined based on these multiple first intermediate value sets. For each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to that set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to that set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The first intermediate value set corresponding to the target second intermediate value is used to synchronize the time of a specified node, which includes the multi-source fusion node or nodes other than the multi-source fusion node.

[0029] When there is only one intermediate value set, the elements in the first intermediate value set are one or more, and the first intermediate value set is used to synchronize the time of the specified node.

[0030] Thirdly, this application provides a time synchronization method for a power distribution network. The power distribution network adopts a hierarchical networking approach and includes multiple layers of nodes. The node at layer 0 is the master node, and the nodes at other layers are slave nodes. The slave nodes are connected to the upper-layer nodes via power line carrier communication links and / or wireless communication links. Both the master node and the slave nodes are equipped with zero-crossing detection circuits. The time synchronization method is applied to the slave nodes in the power distribution network. The time synchronization method includes:

[0031] After the upper-layer node of the slave node completes time synchronization, it receives a time calibration beacon sent by the upper-layer node. The time calibration beacon contains time synchronization information, which includes: the time value of the time calibration beacon's transmission time, and the NTB time difference between the transmission time and the first zero-crossing time of the phase line where the upper-layer node that sent the time calibration beacon is located. The time value of the time calibration beacon's transmission time is based on the local clock of the upper-layer node that sent the time calibration beacon.

[0032] Obtain the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located;

[0033] The slave node is synchronized with the time information in the received time calibration beacon and the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located.

[0034] The upper-level nodes of the slave nodes include: the master node, which is a designated node in the power distribution network, or a node that performs time synchronization through the designated node. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time synchronization sources. The designated node in the power distribution network is synchronized with the time through the multi-source fusion node in the following manner:

[0035] Obtain multiple time signals from multiple different time signal sources;

[0036] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0037] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple second intermediate values ​​are determined based on these sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to that set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to that set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0038] When there is only one intermediate value set, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0039] Fourthly, this application provides a time synchronization method for a power distribution network. The power distribution network adopts a hierarchical networking approach and includes multiple layers of nodes. The nodes at layer 0 are master nodes, and the nodes at other layers are slave nodes. The master node is connected to the lower-level slave nodes via a power line carrier communication link and / or a wireless communication link. Both the master node and the slave nodes are equipped with zero-crossing detection circuits. The time synchronization method is applied to the master node in the power distribution network. The time synchronization method includes:

[0040] After time synchronization is completed, a time calibration beacon is sent to the lower-level slave node to synchronize the lower-level slave node's time. The time calibration beacon contains time synchronization information so that the lower-level slave node can synchronize its local time based on the time synchronization information in the time calibration beacon and the NTB time difference between the time calibration beacon's reception time and the zero-crossing time of the phase line where the lower-level slave node is located. The time synchronization information includes: the time value of the time calibration beacon's transmission time and the NTB time difference between the transmission time and the zero-crossing time of the phase line where the master node is located. The time value of the time calibration beacon's transmission time is based on the master node's local clock.

[0041] The master node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time synchronization sources. The designated node in the power distribution network is synchronized with time through the multi-source fusion node in the following manner:

[0042] Obtain multiple time signals from multiple different time signal sources;

[0043] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0044] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple second intermediate values ​​are determined based on these sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to that set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to that set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0045] When there is only one intermediate value set, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0046] Fifthly, this application provides a time synchronization method for a power distribution network. The power distribution network adopts a hierarchical networking approach and includes multiple layers of nodes. The time synchronization node and the node being synchronized are located in the same layer, adjacent layers, or across layers, and are connected via a power line carrier communication link and / or a wireless communication link. The time synchronization method is applied to the node being synchronized in the power distribution network, and the time synchronization method includes:

[0047] Obtain first time synchronization information, which is the local clock timing value of the time-synchronized node obtained at a reference time or at a time that has a preset relationship with the reference time;

[0048] Obtain second time synchronization information, which is the local clock timing value of the time synchronization node obtained at the reference time after the time synchronization is completed;

[0049] The time node to be synchronized is synchronized based on the first time synchronization information and the second time synchronization information;

[0050] Wherein, the reference time is the time when the time being synchronized node and the time synchronization node simultaneously receive the reference beacon sent by the reference node; and / or, both the time synchronization node and the time being synchronized node are provided with a zero-crossing detection circuit, the reference time is a specified zero-crossing time, and the specified zero-crossing time includes: the rising edge zero-crossing time and / or the falling edge zero-crossing time;

[0051] The time synchronization node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time sources. The designated node in the power distribution network is synchronized with the time through the multi-source fusion node in the following manner:

[0052] Obtain multiple time signals from multiple different time signal sources;

[0053] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0054] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0055] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0056] Sixthly, this application provides a time synchronization method for a power distribution network. The power distribution network adopts a hierarchical networking approach and includes multiple layers of nodes. The time synchronization node and the node being synchronized are located in the same layer, adjacent layers, or across layers, and are connected via power line carrier communication links and / or wireless communication links. The time synchronization method is applied to the time synchronization nodes in the power distribution network, and the time synchronization method includes:

[0057] After completing the time synchronization, generate the second time synchronization information;

[0058] The second time synchronization information is sent to the node to be synchronized, so that the node to be synchronized can obtain the second time synchronization information and synchronize its time based on the first time synchronization information and the obtained second time synchronization information; the first time synchronization information is the local clock timing value of the node to be synchronized obtained by the node to be synchronized at a reference time or at a time that has a preset relationship with the reference time; the second time synchronization information is the local clock timing value of the node to be synchronized obtained by the node to be synchronized at the reference time after the synchronization is completed.

[0059] Wherein, the reference time is the time when the time being synchronized node and the time synchronization node simultaneously receive the reference beacon sent by the reference node; and / or, both the time synchronization node and the time being synchronized node are provided with a zero-crossing detection circuit, the reference time is a specified zero-crossing time, and the specified zero-crossing time includes: the rising edge zero-crossing time and / or the falling edge zero-crossing time;

[0060] The time synchronization node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time sources. The designated node in the power distribution network is synchronized with the time through the multi-source fusion node in the following manner:

[0061] Obtain multiple time signals from multiple different time signal sources;

[0062] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0063] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0064] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0065] Seventhly, this application provides a time synchronization device for a power distribution network. The power distribution network adopts a hierarchical networking approach and includes multiple layers of nodes. The time synchronization node and the node being synchronized are located in the same layer, adjacent layers, or across layers, and are connected via a power line carrier communication link and / or a wireless communication link. The time synchronization device is disposed at the node being synchronized in the power distribution network. The time synchronization device includes:

[0066] The first time synchronization information acquisition module is configured to acquire first time synchronization information, which is the local clock timing value of the time synchronization node acquired by the time synchronization node at a reference time or at a time that has a preset relationship with the reference time.

[0067] The second time synchronization information acquisition module is configured to acquire second time synchronization information, which is the local clock timing value of the time synchronization node acquired at the reference time after the time synchronization is completed;

[0068] The first time synchronization module is configured to synchronize the time of the time-synchronized node based on the first time synchronization information and the second time synchronization information.

[0069] Wherein, the reference time is the time when the time being synchronized node and the time synchronization node simultaneously receive the reference beacon sent by the reference node; and / or, both the time synchronization node and the time being synchronized node are provided with a zero-crossing detection circuit, the reference time is a specified zero-crossing time, and the specified zero-crossing time includes: the rising edge zero-crossing time and / or the falling edge zero-crossing time;

[0070] The time synchronization node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time sources. The designated node in the power distribution network is synchronized with the time through the multi-source fusion node in the following manner:

[0071] Obtain multiple time signals from multiple different time signal sources;

[0072] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0073] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple second intermediate values ​​are determined based on these multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the timing source corresponding to that set, or based on the timing deviation between the timing times of the timing sources corresponding to that set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The multi-source fusion node is then time-synchronized based on the first intermediate value set corresponding to the target second intermediate value.

[0074] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the multi-source fusion node is time-calibrated according to the first intermediate value set.

[0075] Eighthly, this application provides a time synchronization device for a power distribution network. The power distribution network adopts a hierarchical networking approach and includes multiple layers of nodes. The time synchronization node and the node being synchronized are located in the same layer, adjacent layers, or across layers, and are connected via a power line carrier communication link and / or a wireless communication link. The time synchronization device is disposed at a time synchronization node in the power distribution network. The time synchronization device includes:

[0076] The first time synchronization information generation module is configured to generate the second time synchronization information after the time synchronization is completed;

[0077] The first time synchronization information sending module is configured to send the second time synchronization information to the node to be synchronized, so that the node to be synchronized can obtain the second time synchronization information and synchronize its time based on the first time synchronization information and the obtained second time synchronization information; the first time synchronization information is the local clock timing value of the node to be synchronized obtained by the node to be synchronized at a reference time or at a time that has a preset relationship with the reference time; the second time synchronization information is the local clock timing value of the node to be synchronized obtained by the node to be synchronized at the reference time after the synchronization is completed.

[0078] Wherein, the reference time is the time when the time being synchronized node and the time synchronization node simultaneously receive the reference beacon sent by the reference node; and / or, both the time synchronization node and the time being synchronized node are equipped with a zero-crossing detection circuit, the reference time is a specified zero-crossing time, and the specified zero-crossing time includes: the rising edge zero-crossing time and / or the falling edge zero-crossing time.

[0079] The time synchronization node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time sources. The designated node in the power distribution network is synchronized with the time through the multi-source fusion node in the following manner:

[0080] Obtain multiple time signals from multiple different time signal sources;

[0081] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0082] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0083] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0084] Ninthly, this application provides a time synchronization device for a multi-source fusion node, wherein the multi-source fusion node supports the fusion of multiple different time sources, and the time synchronization device includes: a multi-source time acquisition module and a multi-source time fusion module;

[0085] The multi-source time synchronization acquisition module is configured to acquire multiple time synchronization times from multiple different time synchronization sources.

[0086] The multi-source time synchronization fusion module is configured to determine one or more first intermediate value sets based on the multiple time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources; when there are multiple first intermediate value sets, each first intermediate value set contains multiple elements, and multiple corresponding second intermediate values ​​are determined based on the multiple first intermediate value sets; wherein, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation value between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set; a target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule; the first intermediate value set corresponding to the target second intermediate value is used to synchronize the time of a specified node, wherein the specified node includes the multi-source fusion node or a node other than the multi-source fusion node; when there is only one first intermediate value set, each first intermediate value set contains one or more elements, and the first intermediate value set is used to synchronize the time of the specified node.

[0087] According to embodiments of this application, obtaining multiple time synchronization times from multiple different time synchronization sources includes:

[0088] Obtain a set of preferred time synchronization sources, which includes multiple different preferred time synchronization sources. The preferred time synchronization sources are selected from the multiple different time synchronization sources by evaluating the time synchronization sources and selecting those that meet the evaluation criteria.

[0089] Based on the set of preferred time sources, multiple time synchronization times are obtained from the multiple different preferred time sources.

[0090] According to an embodiment of this application, the time synchronization device further includes:

[0091] The timing error monitoring module is configured to monitor the availability of each preferred timing source in the preferred timing source set; when the number of available preferred timing sources in the preferred timing source set does not meet a preset threshold, the preferred timing source set is redefined.

[0092] Tenthly, this application provides a time synchronization device for a power distribution network. The power distribution network adopts a hierarchical networking method and includes multiple layers of nodes. The nodes at layer 0 are master nodes, and the nodes at other layers are slave nodes. The slave nodes are connected to the upper-layer nodes through power line carrier communication links and / or wireless communication links. Both the master node and the slave node are provided with zero-crossing detection circuits. The time synchronization device is disposed at a slave node in the power distribution network. The time synchronization device includes:

[0093] The upper-layer node time calibration beacon receiving module is configured to receive a time calibration beacon sent by the upper-layer node after the slave node has completed time calibration. The time calibration beacon contains time calibration information, which includes: the time value of the time calibration beacon's transmission time, and the NTB time difference between the transmission time and the first zero-crossing time of the phase line where the upper-layer node that sent the time calibration beacon is located. The time value of the time calibration beacon's transmission time is based on the local clock of the upper-layer node that sent the time calibration beacon.

[0094] The NTB time difference acquisition module is configured to acquire the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located;

[0095] The slave node time synchronization module is configured to synchronize the slave node's time based on the time synchronization information in the received time calibration beacon and the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located;

[0096] The upper-level nodes of the slave nodes include: the master node, which is a designated node in the power distribution network, or a node that performs time synchronization through the designated node. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time synchronization sources. The designated node in the power distribution network is synchronized with the time through the multi-source fusion node in the following manner:

[0097] Obtain multiple time signals from multiple different time signal sources;

[0098] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0099] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0100] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0101] According to embodiments of this application, the slave node is further connected to the lower-level node via a power line carrier communication link and / or a wireless communication link, and the time synchronization device further includes:

[0102] The slave node time calibration beacon sending module is configured to send a time calibration beacon to the lower-level node after the slave node completes time calibration, so that the lower-level node can calibrate its local time according to the time calibration information in the received time calibration beacon.

[0103] Eleventhly, this application provides a time synchronization device for a power distribution network. The power distribution network adopts a hierarchical networking method and includes multiple layers of nodes. The layer 0 node is the master node, and the other layer nodes are slave nodes. The master node is connected to the lower-level slave nodes through a power line carrier communication link and / or a wireless communication link. Both the master node and the slave nodes are provided with zero-crossing detection circuits. The time synchronization device is disposed at the master node in the power distribution network. The time synchronization device includes:

[0104] The master node time calibration beacon sending module is configured to send a time calibration beacon to the lower-level slave node after completing time calibration, so as to realize the time calibration of the lower-level slave node. The time calibration beacon contains time calibration information so that the lower-level slave node can calibrate its local time according to the time calibration information in the time calibration beacon and the NTB time difference between the time calibration beacon's reception time and the zero-crossing time of the phase line where the lower-level slave node is located. The time calibration information includes: the time value of the time calibration beacon's transmission time and the NTB time difference between the transmission time and the zero-crossing time of the phase line where the master node is located. The time value of the time calibration beacon's transmission time is based on the master node's local clock.

[0105] The master node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time synchronization sources. The designated node in the power distribution network is synchronized with time through the multi-source fusion node in the following manner:

[0106] Obtain multiple time signals from multiple different time signal sources;

[0107] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0108] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple second intermediate values ​​are determined based on these sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to that set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to that set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0109] When there is only one intermediate value set, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0110] In a twelfth aspect, embodiments of this application provide a hierarchical time synchronization system for a multi-source wide-area power distribution network. The time synchronization system includes multiple nodes, at least one of which is a multi-source fusion node, supporting the fusion of multiple different time sources. The time synchronization system also includes a terminal wireless device connected to a node in the time synchronization system.

[0111] The multi-source fusion node is configured to synchronize the time of a designated node in the time synchronization system in the following manner, wherein the designated node includes the multi-source fusion node or a node other than the multi-source fusion node:

[0112] Obtain multiple time signals from multiple different time signal sources;

[0113] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0114] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple second intermediate values ​​are determined based on these sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to that set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to that set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0115] When there is only one first intermediate value set, the elements in the first intermediate value set can be one or more, and the specified node is synchronized according to the first intermediate value set;

[0116] The designated node is configured to synchronize the time of other nodes in the time synchronization system after the time synchronization is completed.

[0117] In this system, after completing time synchronization, the node in the time synchronization system connected to the terminal wireless device obtains the time synchronization period of the terminal wireless device based on the time error coefficient and the maximum time synchronization tolerance threshold of the terminal wireless device connected to the node; and performs time synchronization on the terminal wireless device based on the time synchronization period.

[0118] In a thirteenth aspect, an embodiment of this application provides a chip including the time synchronization device described in any one of the seventh to eleventh aspects; or, including a memory and a processor; wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the time synchronization method described in any one of the first to sixth aspects.

[0119] In a fourteenth aspect, an electronic device is provided in an embodiment of this application, including a memory and a processor; wherein the memory is used to store computer instructions, wherein the computer instructions are executed by the processor to implement the time synchronization method according to any one of the first to sixth aspects.

[0120] In a fifteenth aspect, embodiments of this application provide a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the time synchronization method described in any one of the first to sixth aspects.

[0121] In a sixteenth aspect, this application provides a computer program product including computer instructions that, when executed by a processor, implement the time synchronization method described in any one of the first to sixth aspects.

[0122] According to the technical solution provided in this application, an innovative concept of a multi-source fusion node is proposed. This multi-source fusion node can support and fuse time information from multiple different time synchronization sources, and perform time synchronization based on the fused time synchronization. When obtaining the fused time synchronization, one or more first intermediate value sets are first determined based on multiple time synchronization times. When multiple first intermediate value sets exist, multiple second intermediate values ​​are further calculated based on the reliability of the time synchronization source or the deviation value between time synchronization times, and the optimal second intermediate value is selected as the time synchronization benchmark through preset rules. After completing the time synchronization of the specified node, other nodes in the power distribution network are time-synchronized hierarchically based on these synchronized nodes. This improves the accuracy and synchronization of high-precision power distribution service time, thereby enhancing the reliability and stability of the entire power distribution network.

[0123] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0124] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings:

[0125] Figure 1 shows a schematic diagram of a power distribution network structure according to an embodiment of this application;

[0126] Figure 2 shows a schematic diagram of the structure of a multi-source fusion node according to an embodiment of this application;

[0127] Figure 3 shows a schematic diagram of another multi-source fusion node according to an embodiment of this application;

[0128] Figure 4 shows a flowchart of a hierarchical time synchronization method for a multi-source wide-area power distribution network according to an embodiment of this application;

[0129] Figure 5 shows a flowchart of a time synchronization method for a multi-source fusion node according to an embodiment of this application;

[0130] Figure 6 shows a flowchart of a method for obtaining multiple time synchronization times from multiple different time synchronization sources according to a specific embodiment 1 of this application;

[0131] Figure 7 shows a flowchart of the method for determining the preferred time synchronization source set according to specific embodiment 1 of this application;

[0132] Figure 8 shows a schematic diagram of determining the multi-source fusion timing time according to multiple timing times of the multiple different preferred timing sources in specific embodiment 1 of this application;

[0133] Figure 9 shows a flowchart of a method for synchronizing the time of a specified node according to a specific embodiment 2 of this application;

[0134] Figure 10 shows a schematic diagram of the structure of a first mobile communication network and a second mobile communication network according to an embodiment of the present application;

[0135] Figure 11 shows a flowchart of a time synchronization method for a power distribution network according to an embodiment of this application;

[0136] Figure 12 shows a schematic diagram of a power distribution network structure according to an embodiment of this application;

[0137] Figure 13 shows a schematic diagram of the power distribution network structure connection in a specific application scenario according to an embodiment of this application;

[0138] Figure 14 shows a flowchart of a method for a slave node to synchronize its time according to an embodiment of the present application, based on the time synchronization information in the received time calibration beacon and the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located.

[0139] Figure 15 illustrates a schematic diagram of the process from sending a time calibration beacon from an upper-layer node to receiving the time calibration beacon from a slave node according to an embodiment of this application;

[0140] Figure 16 shows a flowchart of another time synchronization method for a power distribution network according to an embodiment of this application;

[0141] Figure 17 shows a flowchart of another time synchronization method for a power distribution network according to an embodiment of this application;

[0142] Figure 18 shows a schematic diagram of another power distribution network structure according to an embodiment of this application;

[0143] Figure 19 shows a schematic diagram of a time synchronization process based on a reference beacon according to a specific embodiment 1 of this application;

[0144] Figure 20 shows a schematic diagram of the time synchronization process in a power distribution network according to a specific embodiment 1 of this application;

[0145] Figure 21 shows a flowchart of another time synchronization method for a power distribution network according to an embodiment of this application;

[0146] Figure 22 shows a flowchart of a method for obtaining the synchronization period of the end wireless device according to an embodiment of the present application based on the time error coefficient of the end wireless device connected to the node and the maximum time synchronization tolerance threshold;

[0147] Figure 23 shows a structural block diagram of a time synchronization device for a power distribution network according to an embodiment of this application;

[0148] Figure 24 shows a structural block diagram of a time synchronization device according to an embodiment of this application;

[0149] Figure 25 shows a structural block diagram of an electronic device according to an embodiment of the present application. Detailed Implementation

[0150] In the following description, exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings to enable those skilled in the art to readily implement them. Furthermore, for clarity, portions unrelated to the description of exemplary embodiments have been omitted from the drawings.

[0151] In this application, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of features, figures, steps, behaviors, components, portions or combinations thereof disclosed in this specification, and are not intended to exclude the possibility of the presence or addition of one or more other features, figures, steps, behaviors, components, portions or combinations thereof.

[0152] It should also be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0153] As mentioned earlier, for power distribution terminals, traditional time synchronization methods often rely on a single time source. However, a single time source has reliability risks, and some commonly used time synchronization methods in existing power systems (such as 5G communication time synchronization and radio wave time synchronization) have inherent limitations that make it difficult to meet the urgent need for high-precision time synchronization of power distribution terminals. Although satellite time synchronization has high accuracy, the high cost of receiving equipment and the fact that the accuracy may decrease or fail to synchronize under certain environmental conditions (such as inside buildings) prevent its widespread adoption in the power system.

[0154] For power distribution networks, in existing technologies, when synchronizing the clocks of all nodes in the network, the master node is used as the reference. The master node broadcasts time synchronization information to the slave nodes, and the slave nodes receive the time synchronization information and adjust their own clocks according to the received information, thereby achieving time synchronization with the master node.

[0155] In the existing time synchronization methods described above, all slave nodes rely on the master node's time synchronization information for synchronization. During the transmission of time synchronization information, due to factors such as network transmission delay and device processing time, the time synchronization information received by the slave nodes will have time deviations. This deviation is particularly noticeable when the network is large-scale or the communication conditions are complex, and it cannot meet the requirements for high-precision time synchronization.

[0156] In addition, the time calibration and synchronization of various terminal meters within the transformer area are affected by the complex electromagnetic environment of the existing power line carrier signal transmission, which is subject to signal attenuation and interference from neighboring areas. This results in a large range of communication delay fluctuations. The relay nodes forward the signal at each level, causing large time synchronization deviations at the transformer area nodes and the accumulation of time synchronization errors at each level. At the same time, the single communication mode has the problems of incomplete coverage and inability to synchronize time at all times.

[0157] In order to meet the high-precision time synchronization requirements of power distribution terminals, improve the time synchronization accuracy of each node in the power distribution network, enhance the reliability and stability of the entire power distribution network, and thus improve the accuracy and synchronization of high-precision power distribution service time, the inventors of this application have made improvements to the time synchronization schemes for power distribution terminals and power distribution networks after careful research and consideration.

[0158] For power distribution terminals:

[0159] On the one hand, the concept of a multi-source fusion node is innovatively proposed. This node can support and fuse time information from multiple different time synchronization sources, and perform time synchronization based on the fused time. This mechanism significantly improves the reliability and accuracy of time synchronization. In existing technologies, most systems rely on a single time synchronization source, making them susceptible to the failure or error of that source. Multi-source fusion time synchronization, by integrating data from multiple time synchronization sources, can effectively reduce the uncertainty caused by a single source and improve the robustness of the system.

[0160] On the other hand, a complex intermediate value processing and optimization mechanism was designed. First, one or more first intermediate value sets are determined based on multiple time synchronization times. These sets are calculated based on time synchronization times from at least two different time synchronization sources. When multiple first intermediate value sets exist, multiple second intermediate values ​​are further calculated based on the reliability of the time synchronization sources or the deviation between time synchronization times. The optimal second intermediate value is selected as the synchronization benchmark according to preset rules. This mechanism can intelligently evaluate the quality of different time synchronization sources and select the most reliable time information as the synchronization benchmark, thereby improving the accuracy of time synchronization.

[0161] For power distribution networks, the traditional single synchronization method of broadcasting network-wide time synchronization information by the master node is abandoned. Instead, a hierarchical time synchronization strategy is adopted. This involves synchronizing the time of designated nodes first, then using these synchronized nodes to synchronize the time of other nodes in the power distribution network. This strategy not only reduces the time synchronization traffic in the network but also improves synchronization efficiency. Existing technologies often use broadcast or flooding methods for time synchronization, resulting in heavy network load and low synchronization efficiency. The hierarchical time synchronization strategy, however, achieves efficient propagation of time synchronization by selectively synchronizing key nodes.

[0162] On the other hand, for end-point wireless devices in power distribution networks, a time synchronization period calculation method based on time error coefficient and maximum time synchronization tolerance threshold is proposed. This method can dynamically adjust the time synchronization period according to the actual situation of the wireless device (such as clock stability, communication delay, etc.), ensuring the accuracy of time synchronization while avoiding unnecessary time synchronization operations, saving resources and energy, and thus reducing energy consumption caused by time synchronization communication. In existing technologies, the time synchronization period for wireless devices often uses fixed values ​​or simple calculation methods, which cannot adapt to the actual needs of different devices.

[0163] Figure 1 shows a schematic diagram of a power distribution network structure according to an embodiment of this application. The power distribution network includes multiple nodes, at least one of which is a multi-source fusion node, which supports the fusion of multiple different time synchronization sources. The power distribution network also includes a terminal wireless device, which is connected to the nodes in the power distribution network.

[0164] In this application, "multi-source fusion node" refers to a power distribution terminal in a power distribution network that can receive and process time signals from multiple different time sources. Generally, this can be achieved by integrating multiple different time synchronization modules into the power distribution terminal to receive and process time signals from multiple different time sources. After receiving the corresponding time signal from the time source, the time synchronization module performs a series of signal processing and decoding operations to extract accurate time information (such as UTC time).

[0165] Typically, based on network planning and factors such as node location, coverage area, and cost budget, nodes located at the network center and on the critical path with good communication conditions are selected as multi-source fusion nodes to better cover and serve the entire power distribution network. As shown in Figure 1, multi-source fusion nodes include, but are not limited to: medium-voltage secondary equipment, such as power distribution MPUs and differential protection devices, as well as intelligent distribution terminals, such as central coordination nodes (CCOs) and proxy coordination nodes (PCOs).

[0166] Among them, the multiple time synchronization sources supported by the multi-source fusion node involve multiple time synchronization sources in air, space, and ground, including but not limited to: satellite time synchronization sources (such as BeiDou, GPS, and low-orbit satellite time synchronization), terrestrial network time synchronization sources (such as Network Time Protocol (NTP) and Precision Time Protocol (PTP), radio wave time synchronization sources (such as longwave time synchronization and shortwave time synchronization), 5G communication time synchronization sources, and new time synchronization sources that have emerged with the development of technology.

[0167] The "multi-source fusion node" in this application can support only two different time synchronization sources, or it can support more than two different time synchronization sources.

[0168] Figure 2 shows a schematic diagram of a multi-source fusion node according to an embodiment of this application. The multi-source fusion node shown in Figure 2 supports two different timing sources: a 5G communication timing source and a satellite timing source. Specifically, the satellite timing module in the multi-source fusion node receives and processes the time signal from the satellite timing source, and the 5G communication timing module receives and processes the time signal from the 5G communication timing source.

[0169] Figure 3 shows a schematic diagram of another multi-source fusion node according to an embodiment of this application. The multi-source fusion node shown in Figure 3 supports four different timing sources, namely: satellite timing source (including: BeiDou, GPS, and low-orbit satellites), terrestrial network timing source, long-wave and short-wave timing source, and 5G communication timing source.

[0170] In addition, the "end wireless device" in this application can be a device that is connected to the smart terminal of the distribution area via a wireless communication link (such as a high-speed wireless HRF communication link, a narrowband wireless communication link, etc.), such as a smart monitoring device, a fault sensor, a temperature and humidity sensor, etc., used to monitor specific parameters or environmental conditions in the power grid and communicate with the smart terminal of the distribution area wirelessly.

[0171] The technical solution provided in the embodiments of this application adopts a hierarchical time synchronization strategy. First, the time of a designated node in the power distribution network is synchronized through a multi-source fusion node. Then, after the time synchronization of the designated node is completed, the time of other nodes in the power distribution network is synchronized based on the synchronized designated node. Finally, the time of the terminal wireless device is synchronized based on the nodes in the power distribution network.

[0172] Figure 4 shows a flowchart of a hierarchical time synchronization method for a multi-source wide-area power distribution network according to an embodiment of this application. As shown in Figure 4, the time synchronization method includes the following steps S410 to S430:

[0173] In step S410, the time of a designated node in the power distribution network is synchronized through the multi-source fusion node in the following manner, wherein the designated node includes the multi-source fusion node or a node other than the multi-source fusion node.

[0174] In step S420, after the designated node completes the time synchronization, the other nodes in the power distribution network are synchronized based on the designated node.

[0175] In step S430, after the nodes in the power distribution network complete time synchronization, the time synchronization period of the terminal wireless device is obtained according to the time error coefficient and the maximum time synchronization tolerance threshold of the terminal wireless device connected to the node; and the terminal wireless device is synchronized according to the time synchronization period.

[0176] For step S410:

[0177] To implement step S410 above, Figure 5 shows a flowchart of a time synchronization method for multi-source fusion nodes according to an embodiment of this application. The time synchronization method includes the following steps S510 to S540:

[0178] In step S510, multiple time synchronization times from multiple different time synchronization sources are obtained;

[0179] In step S520, one or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources.

[0180] In step S530, when there are multiple first intermediate value sets, each set contains multiple elements. Multiple second intermediate values ​​are determined based on these multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The first intermediate value set corresponding to the target second intermediate value is used to synchronize the time of the specified node.

[0181] In step S540, when the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the first intermediate value set is used to synchronize the time of the specified node.

[0182] After performing the above steps S510 to S540, when there are multiple first intermediate value sets, the time of the designated node is synchronized according to the first intermediate value set corresponding to the target second intermediate value; when there is only one first intermediate value set, the time of the designated node is synchronized according to the first intermediate value set.

[0183] The following is a detailed description of steps S510 to S540 above.

[0184] For steps S510 to S540, the embodiments of this application provide two specific implementation methods: Implementation Method 1 and Implementation Method 2. Implementation Method 1 determines a multi-source fusion time based on multiple time synchronization times from multiple different time synchronization sources, and uses the multi-source fusion time synchronization time to synchronize the time of the specified node. Implementation Method 2 determines time synchronization optimization parameters based on the time synchronization time deviation values ​​calculated from multiple time synchronization times from multiple different time synchronization sources, combined with a moving average filtering algorithm improved based on Pearson correlation, and uses the time synchronization optimization parameters to synchronize the time of the specified node.

[0185] For specific implementation method 1:

[0186] Figure 6 shows a flowchart of a method for obtaining multiple time synchronization times from multiple different time synchronization sources according to a specific embodiment 1 of this application. As shown in Figure 6, the method includes the following steps S610-620:

[0187] In step S610, a preferred time synchronization source set is obtained. The preferred time synchronization source set includes multiple different preferred time synchronization sources. The preferred time synchronization sources are time synchronization sources that meet the evaluation conditions by evaluating the multiple different time synchronization sources.

[0188] In step S620, multiple time synchronization times from the multiple different preferred time synchronization sources are obtained based on the preferred time synchronization source set.

[0189] For step S610, Figure 7 shows a flowchart of the method for determining the preferred time synchronization source set according to specific embodiment 1 of this application. As shown in Figure 7, determining the preferred time synchronization source set includes the following steps S710 to 730:

[0190] In step S710, the time source evaluation index of the multiple different time source is obtained, wherein the time source evaluation index is used to evaluate the availability of the time source.

[0191] Specifically, the evaluation indicators for the timing source include, but are not limited to: timing signal quality, timing accuracy, timing reliability, and long-term availability.

[0192] The quality of the timing signal refers to the ability of the time signal emitted by the timing source to maintain its integrity and accuracy during transmission. A high-quality timing signal can ensure that the time information obtained by the receiver is accurate. Parameters related to the quality of the timing signal include signal strength, signal-to-noise ratio (SNR), and jitter rate.

[0193] Time synchronization accuracy refers to the deviation between the time information provided by the time synchronization source and the standard time (such as UTC). A high-precision time synchronization source can provide time information that is closer to the standard time. When acquiring time, it can be done through direct comparison: comparing the time information provided by the time synchronization source with a known high-precision time standard (such as GPS time or atomic clock time) and calculating the deviation between the two. Alternatively, it can be done through statistical analysis: acquiring the time information from the time synchronization source multiple times over a period of time and calculating the statistical values ​​(such as mean, standard deviation, etc.) of the deviations between these time information and the standard time to assess the long-term accuracy stability of the time synchronization source. Detailed information on time synchronization accuracy can also be found in the user manual and documentation of the time synchronization source.

[0194] Time synchronization reliability refers to the degree of trustworthiness of the time information provided by a time synchronization source. A highly reliable time synchronization source can stably and reliably provide accurate time information. During acquisition, synchronization can be assessed through synchronization detection, i.e., by comparing the synchronization between the time information provided by the time synchronization source and the time pulse signal. This includes monitoring parameters such as the frequency, phase, and pulse width of the time pulse signal from the time synchronization source and calculating its deviation from the standard time pulse signal. Alternatively, failure rate statistics can be used, i.e., counting the number of failures and the duration of failures of the time synchronization source over a period of time to evaluate its stability and reliability.

[0195] Long-term availability refers to the ability of a time source to remain available and stably provide time information over a long period. A time source with high long-term availability ensures the continuity and stability of system time. Acquisition can be achieved by statistically analyzing available time over a preset time period (e.g., one year, one month), or by evaluating fault recovery capabilities. This involves assessing the time source's ability to resume providing valid time information after a failure, including the speed of recovery and post-recovery stability.

[0196] According to an embodiment of this application, obtaining the time signal source evaluation index of the plurality of different time signal sources includes:

[0197] Obtain the current time synchronization mode, which includes one of the following: normal time synchronization mode, emergency time synchronization mode, high-precision time synchronization mode, regional time synchronization mode, and backup time synchronization mode; obtain the time synchronization source evaluation index of the multiple different time synchronization sources under the current time synchronization mode.

[0198] The standard time synchronization mode is the basic mode used by the time synchronization system during normal operation. In this mode, the system selects multiple stable and reliable clock sources for fusion to ensure high accuracy and stability of time. These clock sources may include satellite navigation systems (such as GPS, BeiDou, etc.), ground atomic clocks, and radio time synchronization stations. The standard time synchronization mode is suitable for most application scenarios and can provide time synchronization services that meet daily needs.

[0199] The high-precision time synchronization mode is designed for applications requiring extremely high time accuracy. This mode prioritizes the highest precision signal source in the satellite navigation system and combines it with a high-precision atomic clock on the ground for time calibration to achieve time synchronization accuracy at the nanosecond or even picosecond level. The high-precision time synchronization mode is suitable for fields such as scientific research, financial transactions, and satellite navigation that require extremely high time accuracy.

[0200] Regional time synchronization mode is used when an independent time synchronization network needs to be built within a specific region due to geographical, political, or technical reasons. This mode utilizes clock sources within the region (such as regional atomic clocks, radio time stations, etc.) to provide time services to users within the region. Regional time synchronization mode can ensure time synchronization accuracy and stability within a specific region and is suitable for application scenarios requiring regional time consistency, such as power systems, communication systems, and transportation systems.

[0201] Backup time synchronization mode is designed to prevent time service interruptions due to the failure of the primary time synchronization source. In this mode, the system configures a backup time synchronization source. When the primary time synchronization source fails, the system automatically switches to the backup source to ensure the continuity and reliability of time services. Backup time synchronization mode is suitable for application scenarios with high requirements for time service continuity, such as financial transactions, power systems, and transportation systems.

[0202] In this application, the evaluation metrics for the time synchronization source will differ under different time synchronization modes to meet the time synchronization requirements of various application scenarios and needs. For example, the evaluation metrics for the time synchronization source corresponding to the conventional time synchronization mode may include: time synchronization accuracy, time synchronization reliability, long-term availability, and stability indicators; the evaluation metrics for the time synchronization source corresponding to the high-precision time synchronization mode may include: time synchronization signal quality, time synchronization accuracy, time synchronization reliability, and long-term availability; and the evaluation metrics for the time synchronization source corresponding to the emergency time synchronization mode may include: time synchronization signal quality, time synchronization accuracy, time synchronization reliability, coverage, and response time.

[0203] The evaluation indicators for the time synchronization source corresponding to each time synchronization mode can be set according to the specific application scenario and project requirements.

[0204] This application, by acquiring time source evaluation metrics based on the current time synchronization mode when obtaining multiple different time synchronization sources, can significantly improve the accuracy and stability of time synchronization. It also allows for more targeted selection and configuration of time synchronization sources, avoiding unnecessary resource waste. Furthermore, selecting and configuring clock sources according to mode requirements simplifies the system structure, reduces system complexity, and improves system maintainability and scalability. Additionally, it enables the system to flexibly switch time synchronization strategies in different scenarios to meet diverse application needs. This helps the system better adapt to complex and ever-changing network environments and clock source status changes, improving system robustness and reliability.

[0205] In step S720, a utility function is constructed based on the time synchronization source evaluation index, and the utility value of the multiple different time synchronization sources is calculated using the utility function.

[0206] The step of constructing a utility function based on the time synchronization source evaluation index and calculating the utility values ​​of the multiple different time synchronization sources using the utility function includes:

[0207] Obtain the timing signal strength and / or timing signal signal-to-noise ratio and / or timing signal jitter rate of each timing source, and obtain a score for the timing signal quality of each timing source based on the timing signal strength and / or timing signal signal-to-noise ratio and / or timing signal jitter rate of each timing source.

[0208] Obtain the timing accuracy of each timing source, and obtain a score for the timing accuracy of each timing source based on the timing accuracy of each timing source;

[0209] The reliability of each time synchronization source is determined by comparing the synchronization of the time synchronization time with the time pulse signal of each time synchronization source. This includes: monitoring the frequency of the time pulse signal of each time synchronization source, calculating the pulse deviation of each time synchronization source, and obtaining a score of the reliability of each time synchronization source based on the pulse deviation of each time synchronization source.

[0210] The available time of each time source within a preset time period is statistically analyzed. The long-term availability of each time source is obtained based on the available time of each time source within the preset time period. The long-term availability score of each time source is obtained based on the long-term availability score of each time source.

[0211] The utility value of each time source is calculated using the following utility function, constructed based on the time signal quality score, the time accuracy score, the time reliability score, and the long-term availability score: U i =αQ i +βP i +γR i +δA i ;

[0212] Among them, U i Let Q represent the utility value of the i-th time source. i P represents the score of the timing signal quality of the i-th timing source, where α represents the weight of the timing signal quality of the i-th timing source; i R represents the score of the timing accuracy of the i-th timing source, and β represents the weight of the timing accuracy of the i-th timing source; i γ represents the timekeeping reliability score of the i-th timekeeping source; γ represents the weight of the timekeeping reliability of the i-th timekeeping source; A i Let δ represent the long-term availability score of the i-th time synchronization source, and let δ represent the weight of the long-term availability of the i-th time synchronization source. The weights of the evaluation indicators for each time synchronization source can be determined based on the actual application scenario and requirements.

[0213] When obtaining the scores of each time synchronization source evaluation index, the data of each time synchronization source evaluation index can be standardized, and then the scoring rules can be set according to the standardized data. For example, all time synchronization accuracy values ​​can be converted into deviations relative to a certain benchmark (such as second level or millisecond level), and then the scoring rules can be set according to the deviation of time synchronization accuracy. The smaller the deviation, the higher the score. Specifically, piecewise functions or linear functions can be used to map the deviation to the scoring range.

[0214] In step S730, the multiple different time synchronization sources are sorted from high to low according to the utility value, and a preset number of time synchronization sources are selected to form the preferred time synchronization source set based on the sorting result.

[0215] The preset quantity can be determined based on actual needs and application scenarios, and it represents the optimal number of time synchronization sources that the system can support or use.

[0216] For step S620, when obtaining multiple timing times from the multiple different preferred timing sources based on the preferred timing source set, in order to reduce timing errors and ensure that the multiple timing times are timing times for the same moment, it is necessary to ensure that the sending of the timing request and the receiving of the timing response are completed in the shortest possible time, so as to minimize the inconsistency of the return time between different timing sources. For example, timing requests can be sent in parallel to all preferred timing sources. This means that timing requests are sent to each timing source at almost the same time (milliseconds or less), which can be achieved through multithreading, asynchronous programming, etc. Then, when sending each timing request, the precise timestamp of the request is recorded. When a timing response is received from each timing source, the precise timestamp of the received response is also recorded. Then, the timestamp of the timing source (the time when the timing source generated the response) is extracted from the timing response. For each timing source, the sending and receiving timestamps are used to calculate network latency and possible clock skew. The calculated time skew is used to correct the timing time received from the timing source. By subtracting the estimated values ​​of network latency and clock skew from the timestamp of the timing source, a value closer to the actual specified historical time can be obtained.

[0217] For step S520 above, there are two cases. The first case is to determine a first intermediate value set based on the multiple time synchronization times. The second case is to determine one or more first intermediate value sets based on the multiple time synchronization times.

[0218] In the first scenario, according to an embodiment of this application, determining a first intermediate value set based on the plurality of timing times includes:

[0219] The timing accuracy and overall reliability of each timing source are obtained; wherein the overall reliability is determined based on the stability parameters, accuracy parameters and environmental factors of the corresponding timing source.

[0220] The timing accuracy range of each timing source is determined based on its timing accuracy.

[0221] The reliability density of each time source is determined based on its time accuracy range and overall reliability, wherein the reliability density is the overall reliability divided by the length of the time accuracy range.

[0222] The reliability density of each time synchronization source is normalized.

[0223] The multi-source fusion timing time is calculated based on the timing time of each timing source and the reliability density of each timing source after normalization, and the multi-source fusion timing time forms the first intermediate value set.

[0224] According to an embodiment of this application, the step of calculating the multi-source fusion timing time based on the timing time of each timing source and the normalized reliability density of each timing source includes:

[0225] The multi-source fusion timing time t is calculated using the following formula. d :

[0226] Among them, t i d represents the timing of the i-th timing source; i Let be the normalized confidence density of the i-th time signal source. n represents the total number of time synchronization sources.

[0227] The first set of intermediate values ​​is used to synchronize the time of the specified node in the following ways:

[0228] The time of the designated node is synchronized using the multi-source fusion time synchronization.

[0229] This application introduces the concept of comprehensive reliability when calculating the reliability density of time synchronization sources. By comprehensively considering the stability parameters, accuracy parameters, and environmental factors of the preferred time synchronization sources, the comprehensive reliability is determined. This allows for a more comprehensive evaluation of the reliability of each time synchronization source. This helps to identify and eliminate time synchronization sources that are accurate in the short term but have poor long-term stability or are greatly affected by the environment, thereby improving the long-term stability and reliability of the entire time synchronization system. Specifically, the introduction of environmental factors in calculating the comprehensive reliability allows for dynamic adjustment of the comprehensive reliability to reflect the real-time performance of the time synchronization sources under different conditions. This mechanism enhances the adaptability and flexibility of the time synchronization system to different environmental changes, enabling it to maintain high time synchronization accuracy in various application scenarios.

[0230] In addition, when calculating the reference time based on the time of each preferred time source, using the reliability density as a weight allows for a more accurate allocation of the contribution of each time source in the calculation of the reference time. Specifically, time sources with high precision and high reliability will be given higher weights, thereby having a more significant impact on the determination of the final reference time and ensuring the accuracy of the results.

[0231] In the second scenario, according to an embodiment of this application, determining one or more first intermediate value sets based on the plurality of timing times includes:

[0232] Obtain the timing accuracy of each preferred timing source.

[0233] The timing range of each preferred timing source is determined based on its timing accuracy and timing time.

[0234] The intersection interval is determined by comparing the timing ranges of each preferred timing source; wherein, the two endpoints of the intersection interval form the first intermediate value set, and the elements in the first intermediate value set correspond to the two endpoints of the intersection interval.

[0235] In the second case, for steps S530 and S540, when the first intermediate value set is one, the first intermediate value set is used to synchronize the time of the specified node in the following manner:

[0236] The average value of the two interval endpoints in the first intermediate value set is used as the multi-source fusion time synchronization time, and the time synchronization of the specified node is performed using the multi-source fusion time synchronization time.

[0237] In the second scenario, when there are multiple sets of first intermediate values, determining the corresponding multiple second intermediate values ​​based on the multiple sets of first intermediate values ​​includes:

[0238] The second intermediate value corresponding to each set of first intermediate values ​​is determined as follows:

[0239] The timing accuracy range of each preferred timing source corresponding to the first intermediate value set is determined based on the timing accuracy of each preferred timing source corresponding to the first intermediate value set.

[0240] The reliability density of each preferred time source corresponding to the first intermediate value set is determined based on the reliability and time accuracy range of each preferred time source corresponding to the first intermediate value set, wherein the reliability density is the reliability divided by the length of the time accuracy range.

[0241] The second intermediate value corresponding to the first intermediate value set is determined based on the maximum of the reliability densities of each preferred timing source corresponding to the first intermediate value set and the length of the intersection interval corresponding to the first intermediate value set. The second intermediate value is the product of the maximum and the length of the intersection interval.

[0242] According to an embodiment of this application, selecting the target second intermediate value from a plurality of second intermediate values ​​according to a preset rule includes:

[0243] Select the largest of the plurality of second intermediate values ​​as the target second intermediate value;

[0244] The first set of intermediate values ​​corresponding to the target second intermediate value is used to synchronize the time of the specified node in the following ways:

[0245] The average value of the two interval endpoints in the first intermediate value set corresponding to the target second intermediate value is used as the multi-source fusion timing time, and the specified node is synchronized using the multi-source fusion timing time.

[0246] The following example illustrates steps S510-540 above:

[0247] If the timing accuracy and corresponding reliability of each preferred timing source in the preferred timing source set Q are respectively θ i and η i (Where i = 1, 2, 3, ..., n, and n is the number of preferred time sources); the time of each preferred time source corresponds to t. i Then the time synchronization range of each preferred time synchronization source is A. i =[t i -θ i ,t i +θ i The timing accuracy range for each preferred timing source is: [-θ i θ i The timing accuracy interval length is 2θ. i , credibility density z i Then it is:

[0248] The time range interval A of each preferred time source in the preferred time source set Q. i The intersection interval formed by the intersection is B. j (Where j = 1, 2, 3, ..., k, and k is the number of intersection intervals), then: B j =A1∩A2∩....A n ,

[0249] Among them, B j The corresponding time range is [t uj , tvj The two endpoints of the intersection interval are t. uj and t vj The length of the intersection interval is t vj -t uj .

[0250] Figure 8 illustrates a schematic diagram of determining the multi-source fusion timing time based on multiple timing times from multiple different preferred timing sources according to a specific embodiment 1 of this application. As shown in Figure 8, taking an example where the preferred timing source set Q contains two preferred timing sources Q1 and Q2, where Q1 is BeiDou and Q2 is GPS, and GPS and BeiDou have comparable timing accuracy and reliability, then:

[0251] The timing time of Q1 is t0, the timing accuracy is ±20ns, the timing accuracy range is [-20, 20], and the reliability is 95%; the timing time of Q2 is t1, the timing accuracy is ±20ns, the timing accuracy range is [-20, 20], and the reliability is 95%.

[0252] Assuming a 10ns difference between t0 and t1, the intersection interval between GPS and BeiDou is [t1-20, t0+20]. This 30ns interval represents the optimal alternative, resulting in the final multi-source fusion timing time.

[0253] It can be seen that the advantage of using the above scheme to determine the multi-source fusion timing time is that the accuracy can be improved to 15ns, while the reliability density is greatly improved; especially when the reliability of the two satellite sources is higher, the advantages of this method are more obvious.

[0254] When determining the multi-source fusion timing time through the above-described specific implementation method 1, this application uses the average value of the two endpoints of the intersection interval as the multi-source fusion timing time, which can smooth out or offset the errors that may be caused by a single timing source to a certain extent. Since the intersection interval is jointly determined by the timing ranges of multiple preferred timing sources, representing the commonly accepted range of timing time from multiple sources, the average value of its two endpoints is closer to the actual timing time, thereby reducing errors and improving the reliability of timing. Furthermore, when there are multiple intersection intervals, selecting the optimal intersection interval (based on a comprehensive consideration of reliability density and intersection interval length) as the timing benchmark can minimize errors and improve the accuracy of timing.

[0255] According to an embodiment of this application, the time synchronization method further includes:

[0256] Monitor the availability of each preferred time source in the preferred time source set.

[0257] When the number of available preferred time sources in the preferred time source set does not meet the preset number threshold, the preferred time source set is redefined.

[0258] For example, multi-source fusion nodes can be set to support emergency timing mode. When some timing sources cannot provide timing services due to factors such as natural disasters, the evaluation indicators of timing sources are redefined according to the emergency timing mode settings. The timing sources that can provide timing services are verified in accordance with the above-mentioned method of determining the preferred timing source set (steps S710 to 730), and priority is given to selecting timing sources that are autonomous, controllable, and have high long-term stability.

[0259] In addition, multi-source fusion nodes can be configured to support low-power timing mode. The multi-source fusion node evaluates the power consumption of the timing modules corresponding to each timing source. After determining the preferred timing source, it controls other unnecessary timing modules to enter low-power or standby mode; or, it keeps the timing modules corresponding to the timing sources that help improve timing accuracy working; or, it puts the timing modules corresponding to the alternative timing sources in hot standby mode.

[0260] According to an embodiment of this application, monitoring the availability of each preferred time source in the preferred time source set includes:

[0261] The local clock error of the multi-source fusion node after time synchronization is estimated by least squares to generate the first error compensation parameter p1 and the second error compensation parameter p2.

[0262] Based on the operating values ​​t corresponding to the local clock times i-2, i-1, and i of the multi-source fusion node, respectively. i-2 t i-1 t i The first error compensation parameter p1 and the second error compensation parameter p2 are used to obtain the time of the local clock i of the multi-source fusion node for prediction compensation. in,

[0263] Obtain the timing time of each preferred timing source in the preferred timing source set at time i, denoted as t. i1 ,t i2 ,…t in n represents the number of preferred time sources in the preferred time source set.

[0264] Calculate the error between the timing time of each preferred timing source i in the preferred timing source set and the local clock i of the multi-source fusion node in the prediction compensation, where the timing time t of the j-th preferred timing source i is... ij The error ε between the predicted compensation and the time of the local clock i of the multi-source fusion node at time i.0j Recorded as:

[0265] Determine whether each error is greater than a set error threshold. If so, determine that the corresponding preferred time synchronization source is not available, and then delete the corresponding preferred time synchronization source from the set of preferred time synchronization sources.

[0266] The "operating values" mentioned above refer to the time values ​​recorded or measured by the multi-source fusion node at various specific time points (such as i-2, i-1, and i times) under its internal clock source. These time values ​​reflect the time that the multi-source fusion node can maintain itself by relying on its internal clock source (such as a crystal oscillator) in the absence of an external time source.

[0267] This application can eliminate those time sources with poor performance by redefining the preferred set of time sources and introduce new, more accurate time sources, which helps to improve the time accuracy of the entire system and ensure that the time information provided is more accurate and reliable.

[0268] For specific implementation method 2:

[0269] In this application, the technical solution of specific implementation method 2 involves two different time synchronization sources: a time synchronization source to be calibrated and a reference time synchronization source. The time synchronization source to be calibrated includes those time synchronization sources that, due to their inherent limitations, are difficult to meet the high-precision time synchronization requirements of power distribution terminals, such as 5G communication time synchronization sources. The nodes supporting the time synchronization source to be calibrated are synchronized based on the time synchronization optimization parameters determined by the multi-source fusion node to improve time synchronization accuracy.

[0270] In specific implementation 2, the multi-source fusion node is located in a first mobile communication network. The multi-source fusion node supports multiple different timing sources, including a mobile communication air interface timing source and a preset reference timing source. The mobile communication network can be a 5G communication network, or other communication networks that support time calibration via the air interface, such as 5G-Advanced (5G-A), 6th Generation Mobile Networks (6G), or other evolved wireless communication networks. The mobile communication air interface timing source mainly refers to the timing source that provides time synchronization information to the mobile terminal through the air interface (i.e., the air interface) in the mobile communication network. This timing method typically involves the wireless communication process between a base station (such as an eNodeB or gNodeB) and a mobile terminal (such as a mobile phone, IoT device, etc.).

[0271] A reference time source generally refers to a high-precision time point whose acquired time can be accepted by terminals and used as a time standard. When determining a reference time source, multiple factors need to be considered, including stability, reliability, accuracy, and coverage. Priority should be given to time sources with high stability and reliability, high accuracy, and wide coverage. Satellite time sources are often selected as reference time sources due to their high accuracy and wide global coverage. Among them, the high-precision atomic clocks carried on BeiDou satellites can provide time synchronization with nanosecond-level or even higher precision, ensuring the accuracy and high precision of the reference time.

[0272] Meanwhile, the preset reference time source can be updated periodically. By evaluating the supported time sources, the time source with the highest accuracy is selected to replace the preset reference time source. In this way, if the current reference time source fails or its accuracy decreases, it can quickly switch to other high-precision time sources, ensuring that the power distribution and consumption terminal meets the high-precision time synchronization requirements at all times.

[0273] In addition, while relying primarily on a preset reference time source, other time sources can be introduced as alternative reference time sources. When the preset reference time source fails or is interfered with, resulting in the failure to meet the time synchronization conditions, the system can switch to an alternative reference time source and obtain the reference time based on the alternative reference time source to improve the overall reliability and stability of the system.

[0274] Taking 5G communication networks as an example, the current method based on 5G air interface time synchronization is as follows:

[0275] Each wireless base station completes time synchronization. The 5G power distribution terminal obtains the base station's system information (including SIB9) and timing advance (TA value). The 3GPP TS 36.331 and 3GPP TS 38.331 standards define that the base station broadcasts the System Frame Number (SFN) to the terminal device once every 10ms. The SIB9 data block in the SFN data frame contains Coordinated Universal Time (UTC) related information t0. To ensure that signals located in the same subframe but in different frequency domains can arrive at the base station simultaneously, the propagation delay from the base station to the 5G terminal needs to be estimated, and the terminal's signal transmission time adjusted to ensure that the uplink transmission of all terminals is synchronized. By detecting the distance of the uplink signal from the base station, the base station obtains the TA value and feeds it back to the terminal through downlink messages. The terminal adjusts its signal transmission time according to the TA.

[0276] The propagation delay τ from the actual base station to the 5G terminal is derived from the time lead TA. This step involves two cases:

[0277] (a) Initial network access of the terminal DTU. The base station determines the TA value by measuring the received PRACH preamble, and the propagation delay τ1 from the base station to the 5G terminal can be obtained as τ1 = (TA × 512 × T) C ) / 2 μ

[0278] Where TA corresponds to an index value of 0-3846, and T C The minimum time unit for 5G NR is 0.5086ns, and μ is the subcarrier SCS index, including 0, 1, 2, 3, and 4. A higher subcarrier SCS index is preferred, which has the advantages of lower latency error and lower air interface scheduling latency for communication transmission.

[0279] (b) TA value update. Due to reasons such as changes in the base station cell accessed by the terminal or base station restart, the TA still needs to be updated. The base station determines the offset of the TA at this moment by measuring the uplink transmission signal. The propagation delay τ2 in this case is: τ2=[N TA,old +(TA-31)×512×T C ] / 2 μ

[0280] Where, N TA,old Save the previous actual TA adjustment value to the terminal;

[0281] Based on the reference time signal t0 and the propagation delay τ (τ1 and τ2 collectively), the 5G terminal side corrects the time t. z For: t z =t0+τ

[0282] The TA value, determined by measuring the peak value of the signal energy on the wireless side, is affected by factors such as signal-to-noise ratio, number of physical resource blocks, wireless bandwidth, base station restart, and signal changes. To further improve the time accuracy between terminals, this application proposes a 5G base station air interface timing error compensation method, namely: using timing time optimization parameters to further compensate the timing time determined based on the reference time signal t0 and propagation delay τ, so as to improve timing accuracy.

[0283] Figure 9 shows a flowchart of a method for synchronizing the time of a specified node according to a specific embodiment 2 of this application. As shown in Figure 9, the method includes the following steps S910-980:

[0284] In step S910, the timing of n historical moments corresponding to the preset reference timing source is obtained to form a first timing time sequence; where n is a positive integer greater than a preset threshold.

[0285] In step S920, the timing of the mobile communication air interface timing source corresponding to the n historical moments is obtained to form a second timing time sequence.

[0286] In step S930, the timing deviation value between the first timing time series and the second timing time series corresponding to each historical moment is calculated to form the original timing deviation value sequence.

[0287] The original timing deviation value sequence can be obtained by measuring the SFN data frame transmission duration of the 5G base station in 10ms intervals.

[0288] In step S940, the original time synchronization deviation value sequence is subjected to moving average filtering based on each of the preset window length values ​​to generate multiple filtered time synchronization deviation value sequences corresponding to the multiple window length values. The filtered time synchronization deviation value sequences form the first intermediate value set.

[0289] Then: the elements in the first intermediate value set correspond to each sequence value in the filtered time synchronization time deviation value sequence, wherein the filtered time synchronization time deviation value sequence corresponding to the window length value is determined as follows:

[0290] Wherein, ΔT' i ΔT represents the i-th sequence value in the filtered time deviation value sequence, m represents the window length value, and ΔT i-j This represents the ij-th sequence value in the original time synchronization deviation value sequence.

[0291] In step S950, the second intermediate value corresponding to each first intermediate value set is determined as follows:

[0292] The Pearson coefficient p is calculated based on the original timing deviation value sequence and the filtered timing deviation value sequence corresponding to the first intermediate value set, wherein the Pearson coefficient p is the second intermediate value corresponding to the first intermediate value set.

[0293] The Pearson coefficient p is expressed by the following formula:

[0294] Where, ΔT i It is represented by the i-th sequence value in the original time synchronization deviation value sequence. and These are the mean values ​​of the original time synchronization deviation value sequence and the filtered time synchronization deviation value sequence, respectively. It is the covariance of the original time synchronization deviation value sequence and the filtered time synchronization deviation value sequence. and These are the standard deviations of the original time synchronization time deviation value sequence and the filtered time synchronization time deviation value sequence, respectively.

[0295] In step S960, the multiple Pearson coefficients corresponding to the multiple window length values ​​are compared with a preset Pearson coefficient threshold, and the Pearson coefficient that is closest to the preset Pearson coefficient threshold among the multiple Pearson coefficients is taken as the target second intermediate value.

[0296] In step S970, the timing optimization parameters are determined based on the nth sequence value in the filtered timing deviation value sequence corresponding to the target second intermediate value and the air interface transmission delay corresponding to the nth historical moment of the mobile communication air interface timing source.

[0297] Wherein, the timing optimization parameter η n This can be expressed using the following formula:

[0298] Wherein, ΔT' n Let τ be the sequence value of the nth filtered time offset value. n This represents the air interface transmission delay corresponding to the nth historical moment.

[0299] In step S980, the timing of the mobile communication air interface timing source is corrected using the timing optimization parameters, and the corrected timing of the mobile communication air interface timing source is used to synchronize the time of the designated node.

[0300] According to an embodiment of this application, the step of correcting the timing of the mobile communication air interface timing source using the timing optimization parameters includes:

[0301] Obtain the reference time and timing advance (TA) transmitted by the mobile communication air interface timing source;

[0302] The current air interface transmission delay is determined based on the time advance (TA).

[0303] The sum of the current air interface transmission delay and the reference time sent by the mobile communication air interface timing source is taken as the timing time of the mobile communication air interface timing source.

[0304] Based on the time synchronization optimization parameters, the time synchronization time of the mobile communication air interface time synchronization source is corrected using the following formula: t r =t0+τ×(1+η) n ),

[0305] Among them, tr The corrected time of the mobile communication air interface time source is t0, which is the reference time sent by the mobile communication air interface time source, and τ is the current air interface transmission delay.

[0306] According to an embodiment of this application, the designated node includes a mobile communication timing node, which is located in the first mobile communication network or the second mobile communication network, and the mobile communication timing node supports the mobile communication air interface timing source.

[0307] Figure 10 shows a schematic diagram of the structure of a first mobile communication network and a second mobile communication network according to an embodiment of this application. As shown in Figure 10, the first mobile communication network includes at least one mobile communication timing node in addition to the multi-source fusion node. The second mobile communication network includes a mobile communication timing node but does not include a multi-source fusion node. In Figure 10, taking satellite timing as the reference timing source as an example, in order to reduce the number of satellite antennas deployed and reduce maintenance costs, the multi-source fusion node can choose to receive satellite signals through a power divider for satellite timing. The power divider can be selected as active or passive depending on the distance between the multi-source fusion node and the power divider. Other node devices can choose to complete timing and synchronization with the multi-source fusion node or the mobile communication timing node through direct communication, depending on the communication situation.

[0308] The step of correcting the timing of the mobile communication air interface timing source using the timing optimization parameters includes:

[0309] The time synchronization optimization parameters are sent to the mobile communication base station of the first mobile communication network, so that the mobile communication base station in the first mobile communication network carries the time synchronization optimization parameters to synchronize the time of the mobile communication time synchronization node in the first mobile communication network, so that the mobile communication time synchronization node in the first mobile communication network can use the time synchronization optimization parameters to correct the time synchronization of the mobile communication air interface time synchronization source.

[0310] And / or, so that the mobile communication base station of the first mobile communication network transmits the timing optimization parameters back to the mobile communication access layer network (e.g., 5G network), so that the mobile communication access layer network sends the timing optimization parameters to the mobile communication base station in the second mobile communication network, so that the mobile communication base station in the second mobile communication network carries the timing optimization parameters to perform timing synchronization on the mobile communication timing node in the second mobile communication network, so that the mobile communication timing node in the second mobile communication network uses the timing optimization parameters to correct the timing of the mobile communication air interface timing source.

[0311] According to an embodiment of this application, when the first mobile communication network includes multiple multi-source fusion nodes, the time synchronization method further includes:

[0312] Multiple timing optimization parameters determined by the multiple multi-source fusion nodes are sent to the mobile communication base station in the first mobile communication network, so that the mobile base station in the first mobile communication network can determine the final timing optimization parameters based on the multiple timing optimization parameters.

[0313] The system receives multiple timing optimization parameters corresponding to the multiple multi-source fusion nodes sent by the mobile communication base station of the first mobile communication network. For example, if the first mobile communication network includes three multi-source fusion nodes: the first multi-source fusion node, the second multi-source fusion node, and the third multi-source fusion node, then the three timing optimization parameters corresponding to them are η1, η2, and η3, respectively.

[0314] The timing of the mobile communication air interface timing source is corrected using the multiple timing optimization parameters to obtain the corresponding multiple corrected timing of the mobile communication air interface timing source.

[0315] Specifically, the timing of the mobile communication air interface timing source is corrected using the following formula: t r =t0+τ×(1+η) n ),

[0316] Among them, t r The corrected time of the mobile communication air interface time source is t0, which is the reference time transmitted by the mobile communication air interface time source, and τ is the current air interface transmission delay. n Optimize the timing parameters.

[0317] Assumptions: At the same time, for the first multi-source fusion node, the second multi-source fusion node, and the third multi-source fusion node, the reference time transmitted by the mobile communication air interface timing source is t0. The current air interface transmission delays of the first multi-source fusion node, the second multi-source fusion node, and the third multi-source fusion node are τ1, τ2, and τ3, respectively. Then, for the first multi-source fusion node: based on the above formula, η1, η2, and η3 are used to correct t0 based on τ1, respectively, to obtain the corresponding corrected timing times of the mobile communication air interface timing sources as t. 11 t 21 and t 31 For the second multi-source fusion node: based on the above formula, η1, η2, and η3 are used respectively to correct t0 based on τ2, and the corresponding corrected timing times of the multiple mobile communication air interface timing sources are t. 12 t 22 and t 32For the third multi-source fusion node: based on the above formula, η1, η2, and η3 are used respectively to correct t0 based on τ3, and the corresponding corrected timing times of the mobile communication air interface timing sources are t. 13 t 23 and t 33 .

[0318] The differences between the timing of the multiple corrected mobile communication air interface timing sources and the timing of the preset reference timing source are calculated respectively to obtain multiple errors corresponding to the multiple timing optimization parameters.

[0319] Assumption: The timing time of the preset reference timing source is t. s For the first multi-source fusion node: the multiple errors corresponding to the multiple timing optimization parameters are t. 11 -t s t 23 -t s and t 31 -t s denoted as: Δt 11 , Δt 21 and Δt 31 For the second multi-source fusion node: the multiple errors corresponding to the multiple timing optimization parameters are t. 12 -t s t 22 -t s and t 32 -t s denoted as: Δt 12 , Δt 22 and Δt 32 For the third multi-source fusion node: the multiple errors obtained corresponding to the multiple timing optimization parameters are t. 13 -t s t 23 -t s and t 33 -t s denoted as: Δt 13 , Δt 23 and Δt 33 .

[0320] Multiple errors corresponding to the multiple timing optimization parameters are sent to the mobile communication base station of the first mobile communication network. After receiving the multiple errors corresponding to the multiple timing optimization parameters sent by each multi-source fusion node, the mobile communication base station of the first mobile network performs a weighted average of the errors calculated by the multiple multi-source fusion nodes using the same timing optimization parameter to obtain multiple weighted average results. The timing optimization parameter of the multi-source fusion node corresponding to the smallest of the multiple weighted average results (i.e., the weighted average result with the smallest error) is sent as the final timing optimization parameter to the multiple multi-source fusion nodes.

[0321] Assumptions: The first, second, and third multi-source fusion nodes each send their locally calculated three errors to the mobile communication base station of the first mobile communication network. Thus, the mobile base station of the first mobile communication network receives all nine errors, denoted as Δt. 11 , Δt 21 , Δt 31 , Δt 12 , Δt 22 , Δt 32 , Δt 13 , Δt 23 and Δt 33 , where Δt 11 , Δt 12 and Δt 13 The first set of errors, Δt, is calculated by the first multi-source fusion node, the second multi-source fusion node, and the third multi-source fusion node respectively using the timing optimization parameter η1 of the first multi-source fusion node. 21 , Δt 22 and Δt 23 The second set of errors, Δt, is calculated by the first, second, and third multi-source fusion nodes respectively using the timing optimization parameter η2 of the second multi-source fusion node. 31 , Δt 32 and Δt 33 The third set of errors is calculated by the first, second, and third multi-source fusion nodes respectively using the timing optimization parameter η3 of the third multi-source fusion node. Each set of errors is added together to obtain three weighted average results, denoted as s1, s2, and s3. The magnitudes of s1, s2, and s3 are compared. Assuming that s2 is the smallest, since s2 corresponds to the timing optimization parameter η2 of the second multi-source fusion node, the timing optimization parameter η2 of the second multi-source fusion node is the final timing optimization parameter.

[0322] The system receives the final timing optimization parameters sent by the mobile communication base station of the first mobile communication network, so as to use the final timing optimization parameters to correct the timing of the mobile communication air interface timing source.

[0323] By using multiple time synchronization optimization parameters determined by multiple multi-source fusion nodes to determine the final time synchronization optimization parameters, and using the final time synchronization optimization parameters to correct the time synchronization time of the time synchronization source to be corrected, the following beneficial effects are achieved:

[0324] 1. Improve time synchronization accuracy:

[0325] By selecting the timing optimization parameters of the multi-source fusion node corresponding to the weighted average result with the smallest error, the timing error can be reduced to the greatest extent and the timing accuracy can be improved.

[0326] 2. Enhance system reliability:

[0327] The participation of multiple terminals and the weighted average processing of the base station ensure that the overall timing performance will not be degraded due to the failure or error of a single terminal, thus enhancing the reliability of the system.

[0328] 3. Highly adaptable:

[0329] This method can adapt to the differences in different network environments and terminal devices. By using multi-source fusion and weighted averaging, it finds the most suitable timing optimization parameters for the current network environment.

[0330] 4. High flexibility:

[0331] Mobile communication base stations can dynamically adjust timing optimization parameters based on received error data, enabling the system to flexibly respond to network changes and equipment updates.

[0332] The system receives the final timing optimization parameters sent by the mobile communication base station of the first mobile communication network, so as to use the final timing optimization parameters to correct the timing of the mobile communication air interface timing source.

[0333] Optionally, the node devices accessing the base station can form a 5G LAN group, and the timing optimization parameters can be multicasted within the group. By forming a LAN group, the node terminals within the group can transmit data between the node devices via multicast based on MAC simplified layer 2 routing, which can further reduce the reliability and security of the transmission.

[0334] According to embodiments of this application, the mobile communication air interface timing source includes cellular communication air interface timing and direct communication timing. The first mobile communication network further includes a non-cellular timing node, which does not support cellular communication air interface timing but supports direct communication timing. The multi-source fusion node or the mobile communication timing node is connected to the non-cellular timing node via a direct communication link. In one specific embodiment, the cellular communication air interface timing is 5G cellular communication air interface timing. The time synchronization method further includes:

[0335] After synchronizing the time of the designated node, delay measurement information is exchanged with the non-cellular time synchronization node via the Precise Time Protocol (PTP) so that the non-cellular time synchronization node can perform time synchronization based on the multi-source fusion node or the mobile communication time synchronization node. Here, the node other than the multi-source fusion node among the designated nodes is the mobile communication time synchronization node.

[0336] According to an embodiment of this application, the interaction of delay measurement information with the non-cellular timing node via the Precise Time Protocol (PTP) so that the non-cellular timing node can perform time synchronization based on the multi-source fusion node or the mobile communication timing node includes:

[0337] The multi-source fusion node or the mobile communication timing node sends a time synchronization command message to the non-cellular timing node at a preset period T. The time synchronization command message includes the time t1 when the time synchronization command message is sent. The time t1 when the time synchronization command message is sent is calibrated according to the air interface timing time of the mobile communication network, the air interface transmission delay, and the air interface transmission delay optimization parameters.

[0338] After receiving the time synchronization instruction message, the non-cellular timing node records the time t2 of receiving the time synchronization instruction message and obtains the time t1 of sending the time synchronization instruction message. Then, it sends a delay measurement request message to the multi-source fusion node or the mobile communication timing node and records the time t3 of sending the delay measurement request message.

[0339] After receiving the delay measurement request message, the multi-source fusion node or the mobile communication timing node records the time t4 of receiving the delay measurement request message and sends a delay measurement response message to the non-cellular timing node. The delay measurement response message contains the time t4 of receiving the delay measurement request.

[0340] After receiving the delay measurement response message, the non-cellular time synchronization node obtains the time t4 of receiving the delay measurement request, and calculates the time delay t based on the time t1 of sending the time synchronization command message, the time t2 of receiving the time synchronization command message, the time t3 of sending the delay measurement request message, and the time t4 of receiving the delay measurement request. delay and time deviation t offset And based on the time t1 when the time synchronization instruction message is sent, and the time delay t delay and the time deviation t offset Time synchronization is performed with the multi-source fusion node or the mobile communication timing node.

[0341] The time delay t is calculated using the following formula. delay :

[0342] t delay = [(t2-t1)+(t4-t3)] / 2,

[0343] The time delay t is calculated using the following formula. offset :

[0344] t offset = [(t2-t1)-(t4-t3)] / 2;

[0345] The non-cellular timing node is based on the time deviation t within a preset period T. offset Calculate the local clock source frequency difference Δf, where Δf i =t offset(i) / T, where i represents the i-th preset period T.

[0346] The non-cellular timing node acquires the clock frequency of the multi-source fusion node or the mobile communication timing node, and uses the clock frequency of the multi-source fusion node or the mobile communication timing node as a reference to correct the frequency difference of the local clock based on the local clock source frequency difference Δf.

[0347] The technical solution provided in this application takes into account the time synchronization of other types of node devices in the mobile communication network, and realizes the time synchronization of node terminals in a wide area.

[0348] For step S420:

[0349] Regarding the time synchronization of other nodes in the power distribution network based on a designated node in the power distribution network, embodiments of this application provide two specific implementation methods: one is a time synchronization method based on a zero-crossing reference, and the other is a time synchronization method based on a reference beacon or power line zero-crossing signal. These are described below.

[0350] Figure 11 shows a flowchart of a time synchronization method for a power distribution network according to an embodiment of this application. The time synchronization method is based on a zero-crossing reference and specifically employs a hierarchical time synchronization strategy based on a hierarchical structure and a zero-crossing reference. It fully utilizes the hierarchical relationship between nodes in the network and the physical characteristic of zero-crossing phase line voltage in the power system to optimize the clock synchronization mechanism in the power distribution network.

[0351] Specifically, firstly, this application introduces the concept of hierarchical time synchronization, meaning that slave nodes receive time synchronization information not only from the master node but also from their direct parent nodes. This allows each node to synchronize its time based on its parent node, reducing communication latency and error accumulation. Secondly, it utilizes the stable and measurable physical phenomenon of zero-crossing phase line voltage in a power system to combine time calibration with power waveforms. Each slave node, while receiving time synchronization information, records the local NTB time difference of the zero-crossing phase line voltage and compares it with the NTB time difference in the time synchronization information, adjusting its local time accordingly to achieve accurate local time calibration. After completing its own time synchronization, each slave node sends a self-calibrated time calibration beacon to the next level node. Thus, the clock synchronization process in the entire network forms a hierarchical transmission and calibration chain. Through hierarchical time synchronization and accurate measurement and comparison of the NTB time difference, the impact of communication latency and error accumulation on time synchronization accuracy is effectively reduced. Simultaneously, the hierarchical time synchronization method also gives the system better fault tolerance and scalability.

[0352] Figure 12 shows a schematic diagram of a power distribution network structure according to an embodiment of this application. As shown in Figure 12, the power distribution network adopts a hierarchical networking method and includes multiple layers of nodes (Figure 12 uses 4 layers as an example). The nodes in the power distribution network are connected through power line carrier communication links and / or wireless communication links. The multiple layers of nodes in the power distribution network include master nodes and slave nodes. The 0th layer node in the power distribution network is the master node, and the other layer nodes are slave nodes. Both the master node and the slave node are provided with zero-crossing detection circuits. The upper layer node of the slave node includes the master node, which is a designated node in the power distribution network or a node that performs time synchronization through a designated node in the power distribution network. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time synchronization sources. Through the multi-source fusion node, the designated node in the power distribution network is synchronized with time based on the first intermediate value set determined in steps S510 to S540 above.

[0353] Specifically, the master node includes, but is not limited to, the Central Coordinating Node (CCO). The CCO manages multiple devices within the distribution area, such as meters and branch switches, and collects and transmits data via broadband carrier communication. Therefore, due to its powerful communication capabilities and crucial role in the distribution area network, the CCO is typically selected as the master node. With the continuous development of technologies such as the Internet of Things (IoT) and edge computing, the master nodes in future power distribution networks may become more diverse. For example, devices with stronger processing capabilities and more integrated functions, such as intelligent converged terminals and edge computing devices, may also become master nodes. In the embodiments of this application, the CCO is used as an example for illustration.

[0354] The slave nodes include, but are not limited to, proxy coordination nodes (PCOs) and / or site coordination nodes (STAs). With the continuous development of IoT technology, more new intelligent devices may be connected to the power distribution network in the future. These devices may possess multiple functions such as data acquisition, processing, and communication, thus becoming new slave nodes. In the embodiments of this application, PCOs and / or STAs are used as exemplary slave nodes for illustration.

[0355] The slave node is connected to the upper-layer node via a power line carrier communication link (e.g., a high-speed power line carrier communication link) and / or a wireless communication link (e.g., a high-speed wireless HRF communication link). In this application, the upper-layer node refers to the direct upper-layer node of the adjacent level.

[0356] Figure 13 shows a schematic diagram of the power distribution network structure in a specific application scenario according to an embodiment of this application. As shown in Figure 13, CCO is the PCO in the first-level node. 1-1 PCO 1-2 STA 1-1 STA 1-2 The upper-level node, PCO 1-1 For the PCO in the second layer node 2-1 STA 2-1 The upper-level node, PCO 1-2 For the PCO in the second layer node 2-2 STA 2-2 STA 2-3 The upper-level node, PCO 2-1 For the STA in the 3rd layer node 3-1 STA 3-2 The upper-level node, PCO 2-2 For STA in the 3rd layer node 3-3 STA 3-4 The upper-level node.

[0357] In the embodiments of this application, both the master node and the slave node are equipped with high-precision zero-crossing detection circuits, which detect the zero-crossing moments of the phase lines. For the master node, a high-precision zero-crossing detection circuit capable of simultaneously detecting the A, B, and C phase power lines can capture each zero-crossing point of these three phase voltages in real time, that is, the instant the voltage crosses zero from positive to negative (or from negative to positive) within each power frequency cycle. Whenever a zero-crossing point of any phase is detected, the master node accurately records the timestamp of that moment, precisely establishing a sequence of the three-phase zero-crossing NTB moments. Unlike the master node, the slave node is typically only responsible for detecting the zero-crossing point of the voltage of the phase (A, B, or C) it is connected to. When the slave node detects a zero-crossing of the voltage of its connected phase line, it also records the timestamp of that moment. Typically, the accuracy of the high-precision zero-crossing detection circuit is around 2 μs.

[0358] The time synchronization method is applied to slave nodes in the power distribution network, as shown in Figure 11. The time synchronization of other nodes in the power distribution network based on the specified node includes the following steps S1110 to S1130:

[0359] In step S1110, after the upper-layer node of the slave node completes time synchronization, it receives a time calibration beacon sent by the upper-layer node. The time calibration beacon contains time synchronization information, which includes: the time value of the time calibration beacon's transmission time, and the NTB time difference between the transmission time and the first zero-crossing time of the phase line where the upper-layer node that sent the time calibration beacon is located. The time value of the time calibration beacon's transmission time is based on the local clock of the upper-layer node that sent the time calibration beacon.

[0360] When a slave node in a power distribution network performs time synchronization, the upper-level node that synchronizes the slave node's time needs to complete its own time synchronization. For example, for PCO2-1 shown in Figure 13, PCO1-1 needs to complete its time synchronization based on the time calibration beacon sent by the CCO before it can send a time calibration beacon to PCO2-1. Then, PCO2-1 performs its own time synchronization based on the time calibration information received from PCO1-1's time calibration beacon. In this way, once the upper-level node completes its time synchronization, it obtains accurate time information, thus establishing a reliable time reference for subsequent time synchronization information sent to the slave node. If the upper-level node's own time is inaccurate, the time synchronization information it sends to the slave node will also contain errors. These errors accumulate as the network expands and time progresses, eventually leading to a significant reduction in the overall time synchronization accuracy of the network. Therefore, ensuring that the upper-level node completes its time synchronization before the slave node performs its own can minimize the accumulation of such errors.

[0361] The transmission time value in the time calibration beacon refers to the specific time point when the upper-layer node sends the message, using its local clock. This transmission time value is used for subsequent time calculations and calibrations by the slave node. The NTB time difference in the time calibration beacon refers to the NTB time difference between the transmission time of the upper-layer node sending the time calibration beacon and the first zero-crossing time of the phase line where the upper-layer node is located. The first zero-crossing time refers to a specific zero-crossing time among multiple zero-crossing times of the phase line where the upper-layer node is located. For example, it could be the zero-crossing time of the phase line voltage from negative to positive closest to the transmission time. It represents a relatively stable and predictable time point and is used as a reference benchmark when sending the time calibration beacon. Since the upper-layer node (master node or slave node) has the capability to acquire the power frequency zero-crossing points of three-phase or single-phase lines and can record the NTB time sequence of three-phase or single-phase zero-crossing points, when specifically acquiring the NTB time difference, the upper-layer node can directly acquire the NTB time difference between the current time and the first zero-crossing time through the zero-crossing detection circuit while sending the time calibration beacon.

[0362] According to embodiments of this application, the NTB time difference includes any one or more of a first NTB time difference, a second NTB time difference, and a third NTB time difference. For example, when the upper-layer node is the master node, the NTB time difference included in the time synchronization information sent by the master node may include the first NTB time difference, the second NTB time difference, and the third NTB time difference. When the upper-layer node is a slave node, and the phase line where the slave node is located is any one of phases A, B, and C, or when the slave node uses any one of the connected phase lines for time synchronization, the NTB time difference included in the corresponding time synchronization information may include any one of the first NTB time difference, the second NTB time difference, and the third NTB time difference, wherein the first NTB time difference, the second NTB time difference, and the third NTB time difference correspond to three different phase lines. In a specific embodiment, the first NTB time difference corresponds to phase line A, the second NTB time difference corresponds to phase line B, and the third NTB time difference corresponds to phase line C.

[0363] For example, for a master node, since it can simultaneously detect the zero-crossing times of phases A, B, and C, when the master node, acting as an upper-level node, sends a time calibration beacon, the time calibration information contains three NTB time differences: the NTB time difference between the time calibration beacon's transmission time and the zero-crossing time of phase A, the NTB time difference between the time calibration beacon's transmission time and the zero-crossing time of phase B, and the NTB time difference between the time calibration beacon's transmission time and the zero-crossing time of phase C. For a slave node, if the slave node can only detect the zero-crossing time of one phase, then when the slave node, acting as an upper-level node, sends a time calibration beacon, it contains only one NTB time difference: the NTB time difference corresponding to the phase line where the upper-level node is located. For example, if the phase line where the upper-level node is located is phase A, then the NTB time difference contained in the time calibration beacon sent by the upper-level node is the NTB time difference between the time calibration beacon's transmission time and the zero-crossing time of phase A.

[0364] In step S1120, the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located is obtained.

[0365] Since the slave node has the capability to acquire single-phase power frequency zero-crossing points and record the single-phase zero-crossing NTB time sequence, when specifically acquiring the NTB time difference, the slave node can directly acquire the NTB time difference between the current time and the second zero-crossing time at the same time as receiving the time calibration beacon through the zero-crossing detection circuit. The second zero-crossing time refers to a specific zero-crossing time among multiple zero-crossing times of the phase line where the slave node is located; for example, it could be the zero-crossing time of the phase line voltage from negative to positive closest to the receiving time.

[0366] Specifically, the first zero-crossing time and the second zero-crossing time can be the same zero-crossing time. For example, if the slave node and the upper-layer node agree to obtain the NTB time difference based on the most recent zero-crossing time, then when the upper-layer node and the slave node are in-phase nodes and the time calibration beacon is transmitted within the same power frequency cycle, the first zero-crossing time and the second zero-crossing time are the same zero-crossing time.

[0367] Alternatively, there may be a preset relationship between the first zero-crossing time and the second zero-crossing time. For example, when the upper-level node and the slave node are in-phase nodes, but the time calibration beacon is transmitted to the slave node after crossing one power frequency cycle, then when the slave node obtains the NTB time difference between the receiving time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located, if the nearest zero-crossing time of the phase line where the slave node is located is used as the second zero-crossing time, then the second zero-crossing time is one power frequency cycle longer than the first zero-crossing time. As another example, when the upper-level node and the slave node are not in-phase nodes, assuming the upper-level node is a phase A node and the slave node is a phase B node, if both the upper-level node and the slave node obtain the NTB time difference based on the nearest zero-crossing time, and the time calibration beacon is transmitted within the same power frequency cycle, then the first zero-crossing time is the nearest phase A zero-crossing time to the transmitting time, and the second zero-crossing time is the nearest phase B zero-crossing time to the receiving time. The difference between the first zero-crossing time and the second zero-crossing time is the time difference between phases A and B. This time difference can be calculated using known methods.

[0368] In step S1130, the slave node is synchronized with time based on the time synchronization information in the received time calibration beacon and the NTB time difference between the receiving time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located.

[0369] Figure 14 shows a flowchart of a method for a slave node to synchronize its time according to an embodiment of this application, based on the time synchronization information in the received time calibration beacon and the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located. As shown in Figure 14, this can be achieved through the following steps S1410 to S1440:

[0370] In step S1410, the time synchronization NTB time difference is obtained based on the time synchronization information, and the time synchronization NTB time difference corresponds to the phase line where the slave node is located.

[0371] The principle of time synchronization of the slave node in this embodiment is to take the time value of the time calibration beacon sent by the upper-layer node as the reference time, obtain the transmission delay between the sending and receiving of the time calibration beacon based on the same zero crossing time or two zero crossing times with a preset relationship, and then adjust the local time to synchronize with its upper-layer node according to the transmission delay and the reference time.

[0372] Based on the possibility that the phase lines of the slave node and the upper-layer node are different, and the fact that the upper-layer node can be either a master node or a slave node, the following three scenarios are considered when obtaining the time-calibration NTB time difference used to calculate the time calibration beacon transmission delay time involved in step S1420:

[0373] The first scenario: When the upper-level node is the master node, that is, when the NTB time difference in the time synchronization information includes the first NTB time difference, the second NTB time difference and the third NTB time difference, the NTB time difference in the time synchronization information corresponding to the phase line where the slave node is located is taken as the time synchronization NTB time difference.

[0374] Figure 15 illustrates a schematic diagram of the process from sending a time calibration beacon from an upper-layer node to receiving the time calibration beacon from a slave node, according to an embodiment of this application.

[0375] As shown in Figure 15, when the master node CCO, acting as an upper-layer node, performs time synchronization with the slave node, the time synchronization information in the time calibration beacon it sends includes three NTB time differences: the NTB time difference ΔT between the time calibration beacon's transmission time and the most recent A-phase zero-crossing time. NTB-A The NTB time difference ΔT between the transmission time of the time calibration beacon and the most recent B-phase zero-crossing time. NTB-B The NTB time difference ΔT between the transmission time of the time calibration beacon and the most recent C-phase zero crossing time. NTB-C .

[0376] When the slave node is phase A STA1 as shown in Figure 4, the slave node does not use all three NTB time differences sent by the master node when performing time synchronization. Instead, it uses the NTB time difference corresponding to its own phase line as the time synchronization NTB time difference for calculating the transmission delay time of the time calibration beacon, that is: ΔT NTB-A .

[0377] Accordingly, when the slave node is phase B STA2 as shown in Figure 15, the slave node is selected as ΔT. NTB-B The time difference NTB is used to calculate the transmission delay time of the calibration beacon; when the slave node is the C-phase STA3 shown in Figure 15, the slave node selects ΔT. NTB-C The time difference NTB is used to calculate the transmission delay time of the time calibration beacon.

[0378] The second scenario: When the upper-layer node is a slave node, that is: when the NTB time difference in the time synchronization information is any one of the first NTB time difference, the second NTB time difference, and the third NTB time difference, and the upper-layer node that sends the time calibration beacon and the slave node are in phase, the NTB time difference in the time synchronization information is used as the time synchronization NTB time difference.

[0379] As shown in Figure 15, when STA1 of phase A performs time synchronization with STA5 of phase A as an upper-layer node, since both phase lines are phase A, STA5 of phase A can directly use the NTB time difference in the time synchronization information sent by STA1 of phase A as the time synchronization NTB time difference for calculating the transmission delay time of the time calibration beacon.

[0380] The third scenario: When the upper-layer node is a slave node, that is: when the NTB time difference in the time synchronization information is any one of the first NTB time difference, the second NTB time difference, and the third NTB time difference, and the upper-layer node that sends the time calibration beacon and the slave node are non-phase nodes, the two NTB time differences in the time calibration beacon sent by the master node corresponding to the phase line where the slave node is located and the phase line where the upper-layer node that sends the time calibration beacon is located are obtained respectively. The difference between the two NTB time differences is obtained, and the difference is subtracted from the NTB time difference in the time synchronization information to obtain the time synchronization NTB time difference.

[0381] In this application, all slave nodes in the power distribution network can receive time synchronization information sent by the master node. However, in the first and second scenarios described above, the slave node only needs to use the time synchronization information sent by the upper-layer node for time synchronization. In the third scenario, since the upper-layer node and the slave node are on different phase lines, the zero-crossing time of the same phase line is required for accurate calculation of the time calibration beacon transmission delay. Therefore, the slave node needs not only the time synchronization information sent by the upper-layer node but also the time synchronization information sent by the master node when performing time synchronization.

[0382] According to an embodiment of this application, it is assumed that: the first NTB time difference corresponds to phase A, the second NTB time difference corresponds to phase B, and the third NTB time difference corresponds to phase C.

[0383] Then: obtaining the two NTB time differences in the time calibration beacon sent by the master node, corresponding to the phase line where the slave node is located and the phase line where the upper-layer node that sent the time calibration beacon is located, respectively, and obtaining the difference between the two NTB time differences, includes:

[0384] If the phase line of the slave node is phase B, then the NTB time difference between the time calibration beacon sent by the master node and the phase line of the slave node is the second NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-BIf the phase line of the upper-layer node that sends the time calibration beacon is phase A, then the NTB time difference between the time calibration beacon sent by the master node and the phase line of the upper-layer node that sends the time calibration beacon is the first NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-A ,but:

[0385] The time difference between the two NTB time differences is obtained using the following formula: ΔT B-A =ΔT′ NTB-B -ΔT′ NTB-A ;

[0386] If the phase line where the slave node is located is phase A, then the NTB time difference between the time calibration beacon sent by the master node and the phase line where the slave node is located is the first NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-A If the phase line of the upper-layer node that sends the time calibration beacon is phase B, then the NTB time difference between the time calibration beacon sent by the master node and the phase line of the upper-layer node that sends the time calibration beacon is the second NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-B ,but:

[0387] The time difference between the two NTB time differences is obtained using the following formula:

[0388] ΔT A-B =ΔT′ NTB-A -ΔT′ NTB-B ;

[0389] If the phase line where the slave node is located is phase A, then the NTB time difference between the time calibration beacon sent by the master node and the phase line where the slave node is located is the first NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-A If the phase line of the upper-layer node that sends the time calibration beacon is phase C, then the NTB time difference between the time calibration beacon sent by the master node and the phase line of the upper-layer node that sends the time calibration beacon is the third NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-C ,but:

[0390] The time difference between the two NTB time differences is obtained using the following formula: ΔT A-C =ΔT′ NTB-A -ΔT′ NTB-C ;

[0391] If the phase line where the slave node is located is phase C, then the NTB time difference between the time calibration beacon sent by the master node and the phase line where the slave node is located is the first NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-C If the phase line of the upper-layer node that sends the time calibration beacon is phase A, then the NTB time difference between the time calibration beacon sent by the master node and the phase line of the upper-layer node that sends the time calibration beacon is the third NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-A ,but:

[0392] The time difference between the two NTB time differences is obtained using the following formula: ΔT C-A =ΔT′ NTB-C -ΔT′ NTB-A ;

[0393] If the phase line where the slave node is located is phase C, then the NTB time difference between the time calibration beacon sent by the master node and the phase line where the slave node is located is the third NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-C If the phase line of the upper-layer node that sends the time calibration beacon is phase B, then the NTB time difference between the time calibration beacon sent by the master node and the phase line of the upper-layer node that sends the time calibration beacon is the second NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-B ,but:

[0394] The time difference between the two NTB time differences is obtained using the following formula: ΔT C-B =ΔT′ NTB-C -ΔT′ NTB-B ;

[0395] If the phase line of the slave node is phase B, then the NTB time difference between the time calibration beacon sent by the master node and the phase line of the slave node is the second NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-C If the phase line of the upper-layer node that sends the time calibration beacon is phase C, then the NTB time difference between the time calibration beacon sent by the master node and the phase line of the upper-layer node that sends the time calibration beacon is the third NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-B ,but:

[0396] The time difference between the two NTB time differences is obtained using the following formula: ΔT B-C =ΔT′ NTB-B -ΔT′ NTB-C ;

[0397] The step of subtracting the NTB time difference from the time synchronization information to obtain the time synchronization NTB time difference includes:

[0398] When the NTB time difference in the time synchronization information is the first NTB time difference ΔT NTB-A And when the phase line where the slave node is located is phase B, the time difference ΔT of the time synchronization NTB is... NTB ΔT is calculated using the following formula: NTB =ΔT NTB-A -ΔT B-A ;

[0399] When the NTB time difference in the time synchronization information is the first NTB time difference ΔT NTB-A And when the phase line where the slave node is located is phase C, the time difference ΔT of the time synchronization NTB is... NTB ΔT is calculated using the following formula: NTB =ΔT NTB-A -ΔT C-A ;

[0400] When the NTB time difference in the time synchronization information is the second NTB time difference ΔT NTB-B And when the phase line where the slave node is located is phase C, the time difference ΔT of the time synchronization NTB is... NTB ΔT is calculated using the following formula: NTB =ΔT NTB-B -ΔT C-B ;

[0401] When the NTB time difference in the time synchronization information is the second NTB time difference ΔT NTB-B And when the phase line where the slave node is located is phase A, the time difference ΔT of the time synchronization NTB is... NTB ΔT is calculated using the following formula: NTB =ΔT NTB-B -ΔT A-B ;

[0402] When the NTB time difference in the time synchronization information is the third NTB time difference ΔT NTB-C And when the phase line where the slave node is located is phase A, the time difference ΔT of the time synchronization NTB is... NTB ΔT is calculated using the following formula: NTB =ΔT NTB-C -ΔT A-C ;

[0403] When the NTB time difference in the time synchronization information is the third NTB time difference ΔT BTB-C And when the phase line where the slave node is located is phase B, the time difference ΔT of the time synchronization NTB is...NTB ΔT is calculated using the following formula: NTB =ΔT NTB-C -ΔT B-C .

[0404] As shown in Figure 15, when phase A STA5 acts as the upper-level node to synchronize the time of the slave node phase B STA6, in this case, phase B STA6 must first select the second NTB time difference ΔT′ in the time calibration beacon sent by the master node. NTB-B The time difference ΔT between the first NTB and the first NTB N ′ TB-A Then, the time difference ΔT between the two NTB time differences is obtained. B-A =ΔT′ NTB-B -ΔT′ NTB-A Then, the NTB time difference ΔT in the time synchronization information sent by phase A STA5 is used. NTB-A Calculate the time difference ΔT between the time synchronization NTB and the time synchronization NTB. NTB =ΔT NTB-A -ΔT B-A In Figure 15, the calculated time difference ΔT between the time synchronization NTB and the time of synchronization is shown. NTB It is a negative value.

[0405] In step S1420, the transmission delay time of the time calibration beacon is calculated based on the time calibration NTB time difference and the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located.

[0406] In step S1430, the calibration time corresponding to the reception time of the time calibration beacon is calculated based on the transmission delay time of the time calibration beacon and the time value of the transmission time in the time synchronization information.

[0407] According to an embodiment of this application, the transmission delay time of the time calibration beacon is calculated using the following formula: T Intv =ΔT NTB-L +nT ABC -ΔT NTB ;

[0408] The calibration time corresponding to the reception time of the time calibration beacon is calculated using the following formula: T P =T Intv +T c ;

[0409] Among them, T P T represents the calibration time corresponding to the reception time of the time calibration beacon; Intv T represents the transmission delay time of the time calibration beacon; c The time value representing the transmission time in the time synchronization information; ΔTNTB-L T represents the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located; ABC ΔT is the power frequency cycle; n is the number of power frequency cycles spanned during the transmission of the time calibration beacon, n≥0, ΔT NTB The time difference is the NTB time difference mentioned above.

[0410] For example, as shown in Figure 15, when the master node CCO, acting as an upper-level node, performs time synchronization for phase A STA1, both the master node CCO and STA1 are set to use the zero-crossing time of the phase line closest to the transmission or reception time as the reference. Since the time calibration beacon is transmitted within one power frequency cycle, n = 0. The first zero-crossing time and the second zero-crossing time are the same zero-crossing time. Therefore, from the time the master node CCO sends the time calibration beacon to the time phase A STA1 receives it, the transmission delay time T of the time calibration beacon is... Intv For: T Intv =ΔT NTB-L -ΔT NTB-A

[0411] For example, as shown in Figure 15, when the master node CCO, acting as an upper-level node, synchronizes the time of phase B STA2, both the master node CCO and STA1 are set to use the zero-crossing time of the phase line closest to the transmission or reception time as the reference. Since phase B STA2 has already crossed one power frequency cycle relative to the transmission time when it receives the time calibration beacon, n=1. The first zero-crossing time and the second zero-crossing time also differ by one power frequency cycle. Therefore, from the time the master node CCO sends the time calibration beacon to the time phase B STA2 receives it, the transmission delay time T of the time calibration beacon is... Intv For: T Intv =ΔT NTB-L +T ABC -ΔT NTB-B

[0412] Phase A STA1 and Phase B STA2 respectively calculate the calibration time corresponding to the reception time of the time calibration beacon using the following formula: T P =T Intv +T c

[0413] For the slave node, it can be determined whether the time calibration beacon was received within the same power frequency cycle or across one or more power frequency cycles in the following way:

[0414] When the slave node receives a time calibration beacon sent by the upper-layer node, it obtains the time value of the reception time of the time calibration beacon, which is timed according to the slave node's local clock. Then, it determines the time difference between the time value of the transmission time of the time calibration beacon and the time value of the reception time of the time calibration beacon. This time difference reflects the clock offset between the slave node and the upper-layer node of the slave node. Then, it compares the time difference with a preset error threshold (e.g., half of one power frequency cycle). If the time difference is less than the preset error threshold, it can be considered that the time calibration beacon was transmitted and received within the same power frequency cycle; otherwise, it is considered that the time calibration beacon was not transmitted and received within the same power frequency cycle. As for how many power frequency cycles were crossed, it can be determined by judging the relationship between the time difference and the preset error threshold. For example, if the time difference contains one preset error threshold, it can be considered that the time calibration beacon was received across one power frequency cycle.

[0415] The above-mentioned judgment method is only one of the specific implementation methods. In specific implementation, other applicable methods can be selected according to the specific situation of the application device.

[0416] In step S1440, time synchronization is performed using the calibration time corresponding to the receiving time of the time calibration beacon.

[0417] T calculated through step S1430 P The timing is based on the local clock of the upper-layer node of the slave node, and the slave node calibrates the local time of the time calibration beacon reception time to T. P This means that time synchronization with the upper-level node has been completed.

[0418] According to an embodiment of this application, the slave node is also connected to the lower-level node via a power line carrier communication link and / or a wireless communication link, and the time synchronization method further includes step S1140:

[0419] In step S1140, after the slave node completes time synchronization, it sends a time calibration beacon to the lower-level node so that the lower-level node can synchronize its local time according to the time synchronization information in the received time calibration beacon.

[0420] In this step S1140, the role of the slave node is transformed into that of the upper layer node of the lower layer node, and the lower layer node is the slave node in the above steps S1110 to S1130. When the lower layer node synchronizes its local time according to the time synchronization information in the received time calibration beacon, it can be done by executing the above steps S1110 to S1130.

[0421] In the time synchronization method of the embodiments of this application, not only do slave nodes need to receive time calibration beacons from upper-layer nodes to perform their own time calibration, but after the slave node completes time synchronization, it also needs to take on the role of sending time calibration beacons to lower-layer nodes. That is, after each slave node completes its own time synchronization, it will become the time calibration source of its lower-layer nodes. This process ensures that time calibration information can be transmitted layer by layer along the network hierarchy, thereby forming a layered time synchronization chain, and finally realizing the time synchronization of all nodes in the entire power distribution network.

[0422] Figure 16 shows a flowchart of another time synchronization method for a power distribution network according to an embodiment of this application. The time synchronization method is applied to the master node in the power distribution network. As shown in Figure 16, the time synchronization of other nodes in the power distribution network based on a designated node in the power distribution network includes the following step S1610:

[0423] In step S1610, after time synchronization is completed, a time calibration beacon is sent to the lower-level slave node to achieve time synchronization of the lower-level slave node. The time calibration beacon contains time synchronization information so that the lower-level slave node can synchronize its local time based on the time synchronization information in the time calibration beacon and the NTB time difference between the time calibration beacon's reception time and the zero-crossing time of the phase line where the lower-level slave node is located. The time synchronization information includes: the time value of the time calibration beacon's transmission time and the NTB time difference between the transmission time and the zero-crossing time of the phase line where the master node is located. The time value of the time calibration beacon's transmission time is based on the master node's local clock.

[0424] The master node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time synchronization sources. The designated node in the power distribution network is synchronized with time through the multi-source fusion node in the following manner:

[0425] Obtain multiple time signals from multiple different time signal sources;

[0426] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0427] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0428] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0429] The phase line where the master node is located includes three phase lines, and the NTB time difference includes a first NTB time difference, a second NTB time difference, and a third NTB time difference, each corresponding to a different phase line. In a specific example, the first NTB time difference corresponds to phase line A, the second NTB time difference corresponds to phase line B, and the third NTB time difference corresponds to phase line C.

[0430] In addition, the time calibration beacon sent by the master node can be received not only by the next lower-level slave nodes, but also by slave nodes in other layers of the power distribution network. However, when other slave nodes perform time calibration, if the slave node being calibrated and its upper-level node are in phase, they can complete the time calibration using only the time calibration information in the time calibration beacon sent by the upper-level node. Only when the slave node being calibrated and its upper-level node are not in phase, they need to combine the time calibration information in the time calibration beacon sent by the master node to complete the time calibration.

[0431] Figure 17 shows a flowchart of another time synchronization method for a power distribution network according to an embodiment of this application. The time synchronization method optimizes the clock synchronization mechanism in the power distribution network based on a reference beacon or power line zero-crossing signal.

[0432] Specifically, in the embodiments of this application, the time synchronization nodes and the time-synchronized nodes are located in the same layer, adjacent layers, or across layers, respectively. This makes the hierarchical time synchronization scheme provided by this application independent of strict hierarchical relationships. When they are in the same layer or adjacent layers, or when the time synchronization nodes and the time-synchronized nodes are directly connected through wireless communication links, the time synchronization nodes and the time-synchronized nodes communicate directly, reducing intermediate links and enabling faster exchange of time synchronization information. This reduces the risk of error accumulation and the time synchronization delay caused by multi-level forwarding of time synchronization information. Furthermore, by introducing the concept of a reference node, the reference time is taken as the reference beacon sent by the reference node simultaneously received by both the time-synchronized node and the time-synchronizing node. The time values ​​recorded by each node at the reference time, based on its local clock, are used as the first and second time synchronization information, respectively. Time synchronization is performed by using the deviation between the first and second time synchronization information. On the one hand, the existence of the reference node provides a reliable reference time trigger source for the entire network. Even if some nodes in the network fail or have large time deviations, they can quickly correct the time by re-receiving the reference beacon, thereby ensuring the time consistency of the entire system. On the other hand, traditional time synchronization methods may require complex protocols or algorithms to ensure time synchronization. However, with the introduction of the reference beacon, nodes only need to record their local time when they receive the reference beacon and perform time synchronization by comparing these time values, which greatly simplifies the time synchronization process and reduces the complexity of implementation. Furthermore, because the current waveform in the power line has a stable periodicity, the position of the zero-crossing point in the power line is relatively stable, predictable, and highly repeatable, and is easy to detect. Using the specified zero-crossing time as the reference time can eliminate errors caused by node clock frequency deviations or phase differences, thereby improving the accuracy of time synchronization. Moreover, in large-scale transformer network, due to the large number and wide distribution of nodes, traditional time synchronization methods may face problems such as signal coverage and communication delays. However, using the zero-crossing signal of the power line itself for time synchronization does not require consideration of these problems, because each node can directly sense these signals through the power line. This helps to achieve efficient and accurate time synchronization of large-scale networks, effectively improving the time synchronization accuracy of transformer network nodes during clock synchronization, and enhancing the reliability and stability of the entire transformer network.

[0433] Figure 18 shows a schematic diagram of another power distribution network structure according to an embodiment of this application. As shown in Figure 18, the power distribution network adopts a hierarchical networking method and includes multiple layers of nodes (Figure 18 uses 4 layers as an example). The nodes in the power distribution network are connected through power line carrier communication links and / or wireless communication links. The multiple layers of nodes in the power distribution network include time synchronization nodes and time-synchronized nodes. The time synchronization nodes and time-synchronized nodes are located in the same layer, adjacent layers, or across layers, respectively. The time synchronization nodes include: designated nodes in the power distribution network, or nodes that perform time synchronization through designated nodes in the power distribution network. The designated nodes include multi-source fusion nodes or nodes other than the multi-source fusion nodes. The multi-source fusion nodes support the fusion of multiple different time synchronization sources. Through the multi-source fusion nodes, the designated nodes in the power distribution network are synchronized based on the first intermediate value set determined in steps S510 to S540 above.

[0434] Unlike existing technologies, according to embodiments of this application, the time synchronization node is not limited to the master node CCO, and the time-synchronized node is not limited to PCO and STA. In specific applications, CCO can also be used as the time-synchronized node, while PCO and STA can also be used as time synchronization nodes. For example, in Figure 13, PCO... 1-2 It can be used as a time synchronization node for the synchronized node CCO and STA. 2-2 STA 2-3 and PCO 2-2 Perform time synchronization.

[0435] Furthermore, according to embodiments of this application, the time synchronization node and the time being synchronized node are located on the same layer, adjacent layers, or across layers, respectively. That is, the time synchronization node and the time being synchronized node can be on the same layer, for example: in Figure 13, STA 1-1 With PCO 1-1 Located on the same floor, STA 1-1 It can be used as a time synchronization node for the PCO of the synchronized node. 1-1 Time calibration can be performed on adjacent or cross-level floors, for example: PCO 1-1 It can be used as a time synchronization node for the time-synchronized node STA. 1-1 PCO 2-1 STA 3-1 and STA 3-2 Time synchronization is performed, including STA 1-1 With PCO 1-1 Located on the same level, PCO 2-1 With PCO 1-1 Located on adjacent layers, STA 3-1 and STA 3-2 With PCO 1-1 Between layers.

[0436] In the technical solution of this application, by allowing direct time synchronization between nodes in the same, adjacent, or cross layers, the number of levels in the time synchronization signal transmission is reduced, thereby significantly shortening the time synchronization path. This decentralized or flattened time synchronization mechanism can greatly improve the time synchronization efficiency of the entire network system, especially in large or complex networks. Furthermore, by simplifying the time synchronization path and reducing hierarchical dependencies, the overall complexity of the system is reduced, making network management and maintenance simpler and more efficient. Simultaneously, this solution can utilize network resources more effectively. For example, when there is a time discrepancy between a PCO and multiple STAs or adjacent PCOs, the PCO can directly synchronize the time with these nodes without going through a CCO, thus saving valuable network bandwidth and transmission time. Therefore, by reducing the transmission delay of the time synchronization signal and the accumulation of errors in intermediate links, this solution can improve the accuracy of time synchronization.

[0437] According to embodiments of this application, the time synchronization node and the time-synchronized node are connected via a power line carrier communication link and / or a wireless communication link. When the time synchronization node and the time-synchronized node are connected across layers, a wireless communication link can be selected to improve time synchronization efficiency.

[0438] In a specific application scenario, the power line carrier communication link includes, but is not limited to, a high-speed power line carrier communication (HPLC) link, and the wireless communication link includes, but is not limited to, a high-speed wireless (HRF) communication link.

[0439] The time synchronization method is applied to the time-synchronized nodes in the power distribution network. As shown in Figure 17, the time synchronization of other nodes in the power distribution network based on a specified node includes the following steps S1710 to S1730:

[0440] In step S1710, first time synchronization information is obtained, which is the local clock timing value of the time-synchronized node obtained at a reference time or at a time that has a preset relationship with the reference time.

[0441] In step S1720, second time synchronization information is obtained, which is the local clock timing value of the time synchronization node obtained at the reference time after the time synchronization node completes the time synchronization.

[0442] In step S1730, the time node to be synchronized is synchronized based on the first time synchronization information and the second time synchronization information.

[0443] Wherein, the reference time is the time when the time being synchronized node and the time synchronization node simultaneously receive the reference beacon sent by the reference node; and / or, both the time synchronization node and the time being synchronized node are equipped with a zero-crossing detection circuit, the reference time is a specified zero-crossing time, and the specified zero-crossing time includes: the rising edge zero-crossing time and / or the falling edge zero-crossing time.

[0444] The time synchronization node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time sources. The designated node in the power distribution network is synchronized with the time through the multi-source fusion node in the following manner:

[0445] Obtain multiple time signals from multiple different time signal sources;

[0446] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0447] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0448] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0449] According to an embodiment of this application, when performing step S1720, that is, when obtaining the second time synchronization information, the second time synchronization information can be obtained by receiving a time calibration beacon sent by the time synchronization node, wherein the time calibration beacon carries the second time synchronization information.

[0450] Upon receiving the time calibration beacon sent by the time synchronization node, the time synchronization method further includes:

[0451] Record the calibration time stamp value, which is the time value of the time being calibrated node corresponding to the time of receiving the time calibration beacon, measured by the local clock.

[0452] The step of synchronizing the time of the node to be synchronized based on the first time synchronization information and the second time synchronization information includes: synchronizing the time of the node to be synchronized using the following formula based on the first time synchronization information, the second time synchronization information, and the calibration time scale value: ts r =tr r -(tt r -tt t );

[0453] Among them, tt r This represents the first time synchronization information, tt t This indicates the second time synchronization information, tr r The calibration timescale value, ts r This represents the local clock timing value of the time-calibrated node after the calibration time stamp value has been calibrated, tt r -tt t This represents the time deviation between the first time synchronization information and the second time synchronization information, reflecting the difference between the clocks of the time synchronization node and the clock of the time being synchronized node.

[0454] According to an embodiment of this application, when a time calibration beacon sent by multiple time synchronization nodes is received, the time synchronization information in the time calibration beacon sent by the time synchronization node that is closest to the time synchronization node, has better communication quality, or has the lowest level among the multiple time synchronization nodes is selected as the second time synchronization information.

[0455] By selecting the time synchronization node that is closest to the node being synchronized in communication, the synchronization can be performed closer to the time source, reducing transmission delay during the time transfer process and thus improving the accuracy of time synchronization.

[0456] By selecting a time synchronization node with better communication quality, time synchronization failures or errors caused by communication problems can be reduced, thereby improving the stability and reliability of the system.

[0457] When a power distribution network synchronizes its time from lower to higher levels, a node at a higher level becomes a synchronization node after synchronizing with a node at a lower level. In this case, considering the additional clock errors caused by synchronizing with each intermediate level, the clock accuracy of the synchronization node at the lower level is higher than that of the synchronization node at the higher level. Therefore, by selecting the lowest-level synchronization node for synchronization, the additional clock errors caused by synchronizing with each intermediate level can be avoided, thereby improving the time synchronization accuracy.

[0458] According to an embodiment of this application, if a time calibration beacon sent by multiple time synchronization nodes is received, the multiple time synchronization nodes include: a first time synchronization node and a second time synchronization node;

[0459] The step of synchronizing the time of the node to be synchronized based on the first synchronization information and the second synchronization information includes:

[0460] When the first time synchronization node is closest to or lowest in communication level with the time-synchronized node relative to the second time synchronization node, the time-synchronized node is synchronized based on the second time synchronization information and the first time synchronization information of the first time synchronization node.

[0461] When the first time synchronization node and the second time synchronization node are at the same level, the signal quality indicators of the first time synchronization node and the second time synchronization node when communicating with the source node of the upper layer are obtained respectively. The corresponding communication quality is evaluated according to the signal quality indicators. The time synchronization node that meets the evaluation conditions is selected from the first time synchronization node and the second time synchronization node according to the communication quality evaluation results. The time synchronization node is synchronized based on the second time synchronization information and the first time synchronization information of the time synchronization node that meets the evaluation conditions.

[0462] Based on the different reference times, this application provides two specific implementation methods: Specific Implementation Method 1 and Specific Implementation Method 2.

[0463] In Specific Implementation 1, the concept of a reference node is introduced, meaning that the power distribution network includes three types of nodes: the time-synchronized node, the time-synchronizing node, and the reference node. The reference time is the moment when the time-synchronized node and the time-synchronizing node simultaneously receive the reference beacon sent by the reference node. The first time synchronization information and the second time synchronization information are the time values ​​recorded by the local clock when the time-synchronizing node and the time-synchronized node simultaneously receive the reference beacon sent by the same reference node. Here, "simultaneously" means "at the same moment," but due to the difference in the local clocks of the time-synchronized node and the time-synchronizing node, the local clock values ​​of the time-synchronized node and the time-synchronizing node may be different for the same moment.

[0464] The nodes in the power distribution network support dual-mode communication. The physical layer of the time synchronization node, the node being synchronized, and the reference node have identical transmit and receive delays under the same communication mode. Therefore, when the reference node simultaneously sends a reference beacon to both the time synchronization node and the node being synchronized, under the same physical transmission conditions (such as similar channel quality, signal strength, and interference levels), the reference beacon theoretically reaches all receiving nodes within the same communication mode simultaneously because the physical layer processing delays (such as modulation, demodulation, and encoding / decoding) are also identical. Furthermore, all nodes in the power distribution network have high-precision timers, ensuring the accuracy and stability of their internal time processing. Thus, the deviation between the time values ​​recorded by the synchronized node and the timer node when they simultaneously receive the reference beacon, based on their respective local clocks, accurately reflects the difference in their local timing. Using the timer node as the synchronization standard, the synchronized node can synchronize its time according to the deviation, achieving time synchronization with the timer node.

[0465] Figure 19 shows a schematic diagram of a time synchronization process based on a reference beacon according to a specific embodiment 1 of this application.

[0466] As shown in Figure 19, STA0 is the reference node, STA1 is the time synchronization node, and STA2-STA4 are the time synchronization nodes, which have accurate clocks.

[0467] When time synchronization begins, the reference node STA0 first sends a reference beacon to the synchronization nodes STA1 and STA2-STA4 using wireless or power line carrier communication. Ignoring transmission delays caused by communication distance, when the synchronized nodes STA2-STA4 receive the reference beacon, they record their own clock values ​​tt2-tt4 corresponding to that time. tt2, tt3, or tt4 constitutes the first time synchronization information. When the synchronization node STA1 and the synchronized nodes STA2-STA4 receive the reference beacon Ts at the same time, the synchronization node STA1 records its own clock value tt1 corresponding to that time. tt1 constitutes the second time synchronization information.

[0468] At any subsequent moment, time synchronization node STA1 sends a time calibration beacon to the time synchronization nodes STA2-STA4, which carries the second time synchronization information tt1. Since STA1 and STA4 are across layers, STA1 can send the time calibration beacon directly to STA4 via a wireless communication link, or it can synchronize the time with STA4 via a relay from STA2. After receiving the time calibration beacon, the time synchronization nodes STA2-STA4 obtain the second time synchronization information tt1 from the beacon and record the calibration time stamp values ​​as tr2, tr3, and tr4, respectively. Then, they calculate the time deviation between the two based on the locally recorded first time synchronization information and the obtained second time synchronization information tt1, for example:

[0469] For the time node STA2 being synchronized, the time deviation between the first and second synchronization information is: tt2-tt1;

[0470] For the time node STA3 being synchronized, the time deviation between the first and second synchronization information is: tt3-tt1;

[0471] For the time node STA4 being synchronized, the time deviation between the first and second synchronization information is: tt4-tt1;

[0472] Finally, the time of each of the time nodes STA2-STA4 is calibrated according to the time deviation calculated for each node. For example, for the time node STA2, the time calibration value ts2 is: ts2 = tr2 - (tt2 - tt1);

[0473] For the time node being calibrated, STA3, the time calibration value ts3 is: ts3 = tr3 - (tt3 - tt1);

[0474] For the time node being calibrated, STA4, the time calibration value ts4 is: ts4 = tr4 - (tt4 - tt1);

[0475] Similarly, in another time synchronization cycle, STA2 can also be used as the time synchronization node to synchronize the time of the time being synchronized node STA4. In this case, ts4 = tr4 - (tt4 - tt2).

[0476] Figure 20 illustrates a time calibration process in a power distribution network according to a specific embodiment 1 of this application. As shown in Figure 20, PCO2 can serve as the reference node for time calibration among CCO, PCO1, STA3, and STA4, with CCO acting as the time calibration node to perform time correction on the time-calibrated nodes PCO1, STA3, and STA4; CCO can serve as the reference node for time calibration among STA2, PCO1, and PCO2, with PCO1 acting as the time calibration node to perform time correction on the time-calibrated nodes STA2 and PCO2; STA3 can receive time calibration beacons broadcast by PCO1 and PCO2 and select the PCO2 with the closest communication distance to complete the time calibration.

[0477] In addition, the roles of the time synchronization node and the time-synchronized node in the power distribution network can be interchanged. For example, as shown in Figure 20, within one time synchronization cycle, PCO1 acts as the time-synchronized node and is synchronized by the time synchronization node PCO2. In another time synchronization cycle, since PCO1 has already been synchronized, it can act as the time synchronization node to synchronize the time-synchronized nodes STA2 and PCO2.

[0478] Unlike Specific Embodiment 1, in Specific Embodiment 2, the nodes in the power distribution network do not include a reference node, but only time-synchronizing nodes and nodes to be synchronized. Both the time-synchronizing nodes and the nodes to be synchronized are equipped with high-precision zero-crossing detection circuits, capable of acquiring the power frequency zero-crossing points of three-phase lines (A / B / C) or single-phase lines, and recording the time values ​​of the zero-crossing moments of the three phases or their respective phase lines. In this case, the reference time is a specified zero-crossing moment, which includes: a rising edge zero-crossing moment and / or a falling edge zero-crossing moment. The specified zero-crossing moment can be one or more, and can be either one type, such as a rising edge zero-crossing moment or a falling edge zero-crossing moment, or multiple types, such as a rising edge zero-crossing moment and a falling edge zero-crossing moment. Thus, the first time synchronization information is the time value recorded by the local clock at one or more specified zero-crossing moments for the phase line where the node to be synchronized is located; the second time synchronization information is the time value recorded by the local clock at one or more specified zero-crossing moments for the phase line where the time-synchronizing node is located. The specified zero-crossing time corresponding to the second time synchronization information can be the same as the specified zero-crossing time corresponding to the first time synchronization information, or it can be a zero-crossing time that has a preset relationship with the specified zero-crossing time corresponding to the first time synchronization information. For example, it can be separated from the specified zero-crossing time corresponding to the first time synchronization information by one or a known number of power frequency cycles, or it can be a zero-crossing time calculated based on a known phase difference.

[0479] The acquisition of the first time synchronization information can be performed before, after, or simultaneously with the acquisition of the second time synchronization information. Similarly, the acquisition of the second time synchronization information can be performed by receiving a time calibration beacon sent by the time synchronization node and obtaining the second time synchronization information from the time calibration beacon.

[0480] After the time-tracking node obtains the first and second time-tracking information, it is necessary to obtain the time values ​​recorded by the local clock for the time-tracking node and the time-tracking node at the same specified zero-crossing time in the same voltage waveform period on the same phase line, based on the first and second time-tracking information. Even if the phase line and voltage waveform period are the same, the first and second time-tracking information may correspond to different zero-crossing points in the same voltage waveform period. Then, the two time deviations are calculated, and finally, the time deviations are used to synchronize the time of the time-tracking node.

[0481] According to an embodiment of this application, when the time node being synchronized is in phase with the time node being synchronized, the time value of the specified zero-crossing moment in the same voltage waveform period corresponding to the first time information is obtained from the second time synchronization information.

[0482] When the time node being calibrated is on a different phase line from the time node being calibrated, the phase difference between the phase line where the time node being calibrated and the time node being calibrated are located is obtained, and the time value of the specified zero crossing moment in the same voltage waveform period of the same phase line corresponding to the first time information is obtained according to the phase difference.

[0483] When there are multiple phase lines where the time synchronization node is located, the time value of the specified zero-crossing moment in the same voltage waveform period of the same phase line corresponding to the first time synchronization information is obtained according to the time value of the specified zero-crossing moment in the first time synchronization information corresponding to the phase line where the time synchronization node is located.

[0484] Calculate the time deviation between the first and second time synchronization information at the same specified zero-crossing time within the same voltage waveform period.

[0485] According to an embodiment of this application, if there are multiple specified zero-crossing times, the average time deviation of the same specified zero-crossing time in the first time synchronization information and the second time synchronization information is calculated, and the average time deviation is used to synchronize the time of the node to be synchronized.

[0486] Specifically, when implementing the step of obtaining the same specified zero-crossing time within the same voltage waveform period corresponding to the first and second time synchronization information, it is necessary to ensure that the time-synchronized node and the synchronization node have recorded data for the same voltage waveform period. This can be achieved through the following three methods:

[0487] Method 1: When the time node being synchronized and the time node are on the same phase line, their recorded voltage waveform periods are synchronized. First, by comparing the timestamps in the first and second time synchronization information, their recorded voltage waveform periods can be determined. Then, after determining the same voltage waveform period, the specified zero-crossing time (e.g., rising edge zero-crossing or falling edge zero-crossing) recorded in the first time synchronization information is found. In the second time synchronization information, the zero-crossing time within the same voltage waveform period corresponding to the specified zero-crossing time in the first time synchronization information is found. This can be achieved by comparing whether the difference between the timestamps is within an acceptable range. Finally, the time value corresponding to the specified zero-crossing time in the first time synchronization information is extracted from the second time synchronization information. This yields the same specified zero-crossing time within the same voltage waveform period corresponding to both the first and second time synchronization information.

[0488] Method 2: When the time node being calibrated and the time node being calibrated are on opposite phase lines, the phase difference between the two phase lines must first be known. This can be obtained through measurement or pre-setting. Then, based on the phase difference, the time value in the second time calibration information is adjusted to match the voltage waveform period of the phase line where the time node being calibrated is located. This may involve adding or subtracting time or time conversion based on the phase difference. After that, in the adjusted second time calibration information, the zero-crossing time in the same voltage waveform period corresponding to the specified zero-crossing time in the first time calibration information is found. This can be achieved by comparing whether the difference between the timestamps of the two is within an acceptable range. Finally, the time value corresponding to the specified zero-crossing time in the first time calibration information is extracted from the adjusted second time calibration information. Thus, the same specified zero-crossing time in the same voltage waveform period corresponding to the first and second time calibration information can be obtained.

[0489] Method 3: When there are multiple phase lines where the time synchronization node is located, firstly, based on the phase line information recorded in the first time synchronization information, determine the specified zero-crossing time corresponding to the phase line where the time synchronization node is located. Then, in the second time synchronization information, find the zero-crossing time in the same phase line with the same voltage waveform period that corresponds to the specified zero-crossing time in the first time synchronization information. Finally, extract the time value corresponding to the specified zero-crossing time in the first time synchronization information from the second time synchronization information.

[0490] When the node being synchronized cannot synchronize its time with the synchronization node, time synchronization can be performed through clock self-sustaining. Specifically, the local clock error of the node being synchronized after multiple synchronizations is estimated by least squares to generate a first error compensation parameter p1 and a second error compensation parameter p2.

[0491] Based on the running values ​​t corresponding to the local clock times i-2, i-1, and i of the time-synchronized node, respectively. i-2 t i-1 t i The first error compensation parameter p1 and the second error compensation parameter p2 determine the time of the local clock at time i of the time-synchronized node for prediction compensation. in,

[0492] The "running values" mentioned above refer to the time values ​​recorded or measured at specific time points (such as i-2, i-1, and i) by the time-controlled node under its internal clock source. These time values ​​reflect the time that the time-controlled node can maintain itself by its internal clock source (such as a crystal oscillator) without being calibrated by the time-controlled node.

[0493] Figure 21 shows a flowchart of another time synchronization method for a power distribution network according to an embodiment of this application. The time synchronization method is applied to time synchronization nodes in the power distribution network. As shown in Figure 21, the time synchronization of other nodes in the power distribution network based on a specified node includes the following steps S2110-2120:

[0494] In step S2110, after the time synchronization is completed, the second time synchronization information is generated.

[0495] In step S2120, the second time synchronization information is sent to the node to be synchronized, so that the node to be synchronized can obtain the second time synchronization information and synchronize its time based on the first time synchronization information and the obtained second time synchronization information; the first time synchronization information is the local clock timing value of the node to be synchronized obtained by the node to be synchronized at a reference time or at a time that has a preset relationship with the reference time, and the second time synchronization information is the local clock timing value of the node to be synchronized obtained by the node to be synchronized at the reference time after the synchronization is completed.

[0496] Wherein, the reference time is the time when the time being synchronized node and the time synchronization node simultaneously receive the reference beacon sent by the reference node; and / or, both the time synchronization node and the time being synchronized node are provided with a zero-crossing detection circuit, the reference time is a specified zero-crossing time, and the specified zero-crossing time includes: the rising edge zero-crossing time and / or the falling edge zero-crossing time;

[0497] The time synchronization node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time sources. The designated node in the power distribution network is synchronized with the time through the multi-source fusion node in the following manner:

[0498] Obtain multiple time signals from multiple different time signal sources;

[0499] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0500] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0501] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0502] According to an embodiment of this application, sending the second time synchronization information to the time-synchronized node includes:

[0503] A time calibration beacon is sent directly or through a relay node to the time-synchronized node, the time calibration beacon carrying the second time synchronization information.

[0504] For step S430:

[0505] Figure 22 shows a flowchart of a method for obtaining the synchronization period of an end wireless device according to an embodiment of the present application, based on the time error coefficient of the end wireless device connected to the node and the maximum time synchronization tolerance threshold. As shown in Figure 22, the method includes the following steps S2210 to S2230:

[0506] In step S2210, the time error coefficients of the terminal wireless device are obtained to form a time error coefficient set Q. α .

[0507] Wherein, the time error coefficient set Q α Notation: Qα ={α1,α2,…α n}; n represents the number of the terminal wireless devices, and the time error coefficient α of the i-th terminal wireless device. i The time interval T between the two time synchronizations performed by the node on the i-th terminal wireless device is based on the time interval T. b And the internal clock time error Δt of the i-th terminal wireless device after the two time synchronizations. i It is calculated using the following formula:

[0508] α i =Δt i / T b , where Δt i =|T i2 -T i1 |,T i1 T is the internal clock time of the i-th end wireless device after the node performs the first time synchronization with the i-th end wireless device. i2 The internal clock time of the i-th end wireless device after the node performs a second time synchronization on the i-th end wireless device.

[0509] In step S2220, the maximum time synchronization tolerance threshold of the terminal wireless device is obtained.

[0510] In step S2230, the maximum time synchronization period of the terminal wireless device is calculated based on the maximum time synchronization tolerance threshold and the set of time error coefficients, forming a maximum time synchronization period set.

[0511] The set of maximum synchronization periods is denoted as {T}. MAX_1 ,T MAX_2 ,…T MAX_n The maximum synchronization period T of the i-th terminal wireless device MAX_i =Δt MAX_i / α i , Δt MAX_i The maximum time synchronization tolerance threshold for the i-th terminal wireless device.

[0512] In step S2240, time slots are allocated according to the maximum synchronization period of the terminal wireless device to obtain the synchronization period of the terminal wireless device.

[0513] According to an embodiment of this application, the step of synchronizing the time of the terminal wireless device according to the synchronization period includes:

[0514] Define the optimization objective:

[0515] Where, p cThe power consumption generated by the node synchronizing the time with the terminal wireless device; Δt c β is the channel time occupied by the node for time synchronization with the terminal wireless device. T T is the threshold value for the channel occupancy ratio when the node performs time synchronization with the terminal wireless device. i Let be the time synchronization period for the i-th terminal wireless device.

[0516] Optimize the timing period {T1,T2,…T} of the terminal wireless device according to the optimization objective. n}

[0517] The terminal wireless device is time-synchronized according to the optimized time synchronization period.

[0518] This application avoids unnecessary frequent time synchronization operations by accurately calculating and utilizing the maximum clock tolerance period of each end wireless device for time synchronization, thereby reducing the energy consumption caused by time synchronization communication. This not only reduces the energy consumption of individual end wireless devices, but also reduces the additional energy consumption caused by communication conflicts and retries by optimizing the overall network communication mode.

[0519] Figure 23 shows a structural block diagram of a time synchronization device for a power distribution network according to an embodiment of this application. The power distribution network adopts a hierarchical networking method and includes multiple layers of nodes. The time synchronization node and the time-synchronized node are located in the same layer, adjacent layers, or across layers, respectively, and are connected through a power line carrier communication link and / or a wireless communication link. The time synchronization device is disposed in the time-synchronized node in the power distribution network. As shown in Figure 23(a), the time synchronization device 2300 includes: a first time synchronization information acquisition module, configured to acquire first time synchronization information, the first time synchronization information being the local clock timing value of the time-synchronized node acquired by the time-synchronized node at a reference time or at a time having a preset relationship with the reference time; a second time synchronization information acquisition module, configured to acquire second time synchronization information, the second time synchronization information being the local clock timing value of the time synchronization node acquired by the time synchronization node at the reference time after completing time synchronization; and a first time synchronization module, configured to synchronize the time of the time-synchronized node based on the first time synchronization information and the second time synchronization information.

[0520] Wherein, the reference time is the moment when both the time-synchronized node and the time-synchronizing node simultaneously receive the reference beacon sent by the reference node; and / or, both the time-synchronizing node and the time-synchronized node are equipped with a zero-crossing detection circuit, the reference time is a specified zero-crossing time, the specified zero-crossing time includes: rising edge zero-crossing time and / or falling edge zero-crossing time; the time-synchronizing node is a designated node in the power distribution network, or a node that performs time synchronization through the designated node, the designated node includes a multi-source fusion node or a node other than the multi-source fusion node, the multi-source fusion node supports the fusion of multiple different time sources, and the designated node in the power distribution network is synchronized through the multi-source fusion node in the following manner:

[0521] Obtain multiple time signals from multiple different time signal sources;

[0522] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0523] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple second intermediate values ​​are determined based on these multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the timing source corresponding to that set, or based on the timing deviation between the timing times of the timing sources corresponding to that set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The multi-source fusion node is then time-synchronized based on the first intermediate value set corresponding to the target second intermediate value.

[0524] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the multi-source fusion node is time-calibrated according to the first intermediate value set.

[0525] According to an embodiment of this application, the time synchronization device further includes:

[0526] The clock self-sustaining module is configured to perform least-squares estimation of the local clock error after multiple time synchronizations, generating a first error compensation parameter p1 and a second error compensation parameter p2; based on the operating values ​​t corresponding to the local clock at times i-2, i-1, and i, respectively. i-2 t i-1 t i The first error compensation parameter p1 and the second error compensation parameter p2 determine the time of the local clock at time i for prediction compensation. in,

[0527] Figure 23 shows a structural block diagram of another time synchronization device for a power distribution network according to an embodiment of this application. The power distribution network adopts a hierarchical networking method and includes multiple layers of nodes. The time synchronization node and the time-synchronized node are located in the same layer, adjacent layers, or across layers, respectively, and are connected through power line carrier communication links and / or wireless communication links. The time synchronization device is set in the time synchronization node in the power distribution network, as shown in Figure 23(b). The time synchronization device 2400 includes: a first time synchronization information generation module, configured to generate second time synchronization information after time synchronization is completed; and a first time synchronization information sending module, configured to send the second time synchronization information to the time-synchronized node so that the time-synchronized node can obtain the second time synchronization information and synchronize the time of the time-synchronized node based on the first time synchronization information and the obtained second time synchronization information. The first time synchronization information is the local clock timing value of the time-synchronized node obtained by the time-synchronized node at a reference time or at a time with a preset relationship with the reference time. The second time synchronization information is the local clock timing value of the time synchronization node obtained by the time synchronization node at the reference time after time synchronization is completed.

[0528] Wherein, the reference time is the time when the time being synchronized node and the time synchronization node simultaneously receive the reference beacon sent by the reference node; and / or, both the time synchronization node and the time being synchronized node are equipped with a zero-crossing detection circuit, the reference time is a specified zero-crossing time, and the specified zero-crossing time includes: the rising edge zero-crossing time and / or the falling edge zero-crossing time.

[0529] The time synchronization node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time sources. The designated node in the power distribution network is synchronized with the time through the multi-source fusion node in the following manner:

[0530] Obtain multiple time signals from multiple different time signal sources;

[0531] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0532] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0533] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0534] Figure 23 shows a structural block diagram of another time synchronization device for a power distribution network according to an embodiment of this application. The power distribution network adopts a hierarchical networking method and includes multiple layers of nodes. The 0th layer node is the master node, and the other layer nodes are slave nodes. The slave nodes are connected to the upper-layer nodes via power line carrier communication links and / or wireless communication links. Both the master node and the slave nodes are equipped with zero-crossing detection circuits. The time synchronization device is located at a slave node in the power distribution network, as shown in Figure 23(c). The time synchronization device 2500 includes: an upper-layer node time calibration beacon receiving module, configured to receive a time calibration beacon sent by the upper-layer node after the upper-layer node of the slave node has completed time synchronization. The time calibration beacon contains time synchronization information, including: the time calibration... The system includes a beacon transmission time value and an NTB time difference between the transmission time and the first zero-crossing time of the phase line where the upper-layer node transmitting the time calibration beacon is located, wherein the transmission time value of the time calibration beacon is timed using the local clock of the upper-layer node transmitting the time calibration beacon; an NTB time difference acquisition module is configured to acquire the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located; and a slave node time synchronization module is configured to synchronize the slave node's time based on the time synchronization information in the received time calibration beacon and the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located.

[0535] The upper-level nodes of the slave nodes include: the master node, which is a designated node in the power distribution network, or a node that performs time synchronization through the designated node. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time synchronization sources. The designated node in the power distribution network is synchronized with the time through the multi-source fusion node in the following manner:

[0536] Obtain multiple time signals from multiple different time signal sources;

[0537] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0538] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0539] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0540] According to embodiments of this application, the slave node is further connected to the lower-level node via a power line carrier communication link and / or a wireless communication link, and the time synchronization device further includes:

[0541] The slave node time calibration beacon sending module is configured to send a time calibration beacon to the lower-level node after the slave node completes time calibration, so that the lower-level node can calibrate its local time according to the time calibration information in the received time calibration beacon.

[0542] Figure 24 shows a structural block diagram of a time synchronization device according to an embodiment of this application. The power distribution network adopts a hierarchical networking method and includes multiple layers of nodes. The nodes at layer 0 are master nodes, and the nodes at other layers are slave nodes. The master node is connected to the lower-level slave nodes through a power line carrier communication link and / or a wireless communication link. Both the master node and the slave nodes are equipped with zero-crossing detection circuits. The time synchronization method is applied to the master node in the power distribution network. As shown in Figure 24(a), the time synchronization device 2600 includes: a master node time calibration beacon sending module, configured to send a time calibration beacon to the lower-level slave nodes after time synchronization is completed. This is to enable time synchronization of the lower-level slave nodes; the time calibration beacon contains time synchronization information so that the lower-level slave nodes can synchronize their local time based on the time synchronization information in the time calibration beacon and the NTB time difference between the reception time of the time calibration beacon and the zero-crossing time of the phase line where the lower-level slave node is located; wherein, the time synchronization information includes: the time value of the transmission time of the time calibration beacon, and the NTB time difference between the transmission time and the zero-crossing time of the phase line where the master node is located, and the time value of the transmission time of the time calibration beacon is based on the local clock of the master node.

[0543] The master node is a designated node in the power distribution network, or a node through which time synchronization is performed. The designated node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports the fusion of multiple different time synchronization sources. The designated node in the power distribution network is synchronized with time through the multi-source fusion node in the following manner:

[0544] Obtain multiple time signals from multiple different time signal sources;

[0545] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0546] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0547] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the time is synchronized to the specified node according to the first intermediate value set.

[0548] Figure 24 shows a structural block diagram of a time synchronization device according to an embodiment of this application. The multi-source fusion node supports fusion time synchronization from multiple different time sources. As shown in Figure 24(b), the time synchronization device 2700 includes: a multi-source time synchronization acquisition module and a multi-source time synchronization fusion module; the multi-source time synchronization acquisition module is configured to acquire multiple time synchronization times from multiple different time sources; the multi-source time synchronization fusion module is configured to determine one or more first intermediate value sets based on the multiple time synchronization times, the first intermediate value sets being determined based on time synchronization times from at least two different time sources; when there are multiple first intermediate value sets, the elements in the first intermediate value sets are multiple, and multiple corresponding first intermediate value sets are determined respectively. Two intermediate values; wherein, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation value between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set; a target second intermediate value is selected from multiple second intermediate values ​​according to a preset rule; the first intermediate value set corresponding to the target second intermediate value is used to synchronize the time of the specified node, the specified node including the multi-source fusion node or nodes other than the multi-source fusion node; when the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the first intermediate value set is used to synchronize the time of the specified node.

[0549] According to embodiments of this application, obtaining multiple time synchronization times from multiple different time synchronization sources includes:

[0550] Obtain a set of preferred time synchronization sources, which includes multiple different preferred time synchronization sources. The preferred time synchronization sources are selected from the multiple different time synchronization sources by evaluating the time synchronization sources and selecting those that meet the evaluation criteria.

[0551] Based on the set of preferred time sources, multiple time synchronization times are obtained from the multiple different preferred time sources.

[0552] According to an embodiment of this application, the time synchronization device 2700 further includes:

[0553] The timing error monitoring module is configured to monitor the availability of each preferred timing source in the preferred timing source set; when the number of available preferred timing sources in the preferred timing source set does not meet a preset threshold, the preferred timing source set is redefined.

[0554] This application also provides a hierarchical time synchronization system for a multi-source wide-area power distribution network. The system includes multiple nodes, at least one of which is a multi-source fusion node, supporting the fusion of multiple different time sources. The system also includes end-user wireless devices connected to the nodes in the system.

[0555] The multi-source fusion node is configured to synchronize the time of a designated node in the time synchronization system in the following manner, wherein the designated node includes the multi-source fusion node or a node other than the multi-source fusion node:

[0556] Obtain multiple time signals from multiple different time signal sources;

[0557] One or more first intermediate value sets are determined based on the plurality of time synchronization times, wherein the first intermediate value sets are determined based on time synchronization times from at least two different time synchronization sources;

[0558] When there are multiple first intermediate value sets, each set contains multiple elements. Multiple corresponding second intermediate values ​​are determined based on each of the multiple first intermediate value sets. Specifically, for each first intermediate value set, a second intermediate value is determined based on the reliability of the time synchronization source corresponding to the first intermediate value set, or based on the time synchronization time deviation between the time synchronization times of the time synchronization sources corresponding to the first intermediate value set. A target second intermediate value is selected from the multiple second intermediate values ​​according to a preset rule. The specified node is then synchronized with the time based on the first intermediate value set corresponding to the target second intermediate value.

[0559] When the first intermediate value set is one, the elements in the first intermediate value set are one or more, and the specified node is time-synchronized according to the first intermediate value set;

[0560] The designated node is configured to synchronize the time of other nodes in the time synchronization system after the time synchronization is completed.

[0561] In this system, after completing time synchronization, the node in the time synchronization system connected to the terminal wireless device obtains the time synchronization period of the terminal wireless device based on the time error coefficient and the maximum time synchronization tolerance threshold of the terminal wireless device connected to the node; and performs time synchronization on the terminal wireless device based on the time synchronization period.

[0562] This application also provides a chip including the time synchronization device as described in any of the above device embodiments; or, including a memory and a processor; wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the time synchronization method as described in any of the above method embodiments.

[0563] Figure 25 shows a structural block diagram of an electronic device according to an embodiment of this application. As shown in Figure 25, the electronic device includes a memory and a processor; wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the time synchronization method as described in any of the above method embodiments.

[0564] This application also provides a computer-readable storage medium, which may be a computer-readable storage medium included in the electronic device or computer system described in the above embodiments; or it may be a standalone computer-readable storage medium not assembled into a device. The computer-readable storage medium stores one or more programs, which are used by one or more processors to execute the time synchronization method described in this application.

[0565] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the time synchronization method described in any one of the claims. Industrial applicability

[0566] This application provides a hierarchical time synchronization method, apparatus, system, and chip for multi-source wide-area power distribution networks. The hierarchical time synchronization method includes determining one or more first intermediate value sets based on multiple time synchronization times. When multiple first intermediate value sets exist, multiple second intermediate values ​​are further calculated based on the reliability of the time synchronization source or the deviation between time synchronization times, and the optimal second intermediate value is selected as the time synchronization benchmark according to preset rules. After completing the time synchronization of a specified node, hierarchical time synchronization is performed on other nodes in the power distribution network based on the synchronized nodes. This improves the accuracy and synchronization of high-precision power distribution service time, thereby enhancing the reliability and stability of the entire power distribution network.

Claims

1. A hierarchical time synchronization method for a multi-source wide-area power distribution network, the power distribution network comprising a plurality of nodes, wherein at least one node is a multi-source fusion node, the multi-source fusion node supporting fusion time synchronization of a plurality of different time sources. The power distribution network further comprises a terminal wireless device connected to a node in the power distribution network; the time correction method comprises: The multi-source fusion node corrects a specified node in the power distribution network in the following manner: obtaining multiple time correction times respectively from multiple different time correction sources; determining one or more first intermediate value sets according to the multiple time correction times, the first intermediate value set being determined according to time correction times from at least two different time correction sources; in the case where the first intermediate value set is multiple, the elements in the first intermediate value set are multiple, a corresponding multiple second intermediate values are determined according to the multiple first intermediate value sets respectively; wherein for each first intermediate value set, the second intermediate value is determined according to the credibility of the time correction source corresponding to the first intermediate value set, or according to the time correction time deviation value between the time correction sources corresponding to the first intermediate value set; a target second intermediate value is selected from the multiple second intermediate values according to a preset rule; the specified node is corrected according to the first intermediate value set corresponding to the target second intermediate value; in the case where the first intermediate value set is one, the element in the first intermediate value set is one or more, the specified node is corrected according to the first intermediate value set; after the specified node completes the correction, other nodes in the power distribution network are corrected based on the specified node; after the nodes in the power distribution network complete the correction, the time correction period of a terminal wireless device connected to the node is obtained according to the time error coefficient of the terminal wireless device and the maximum time synchronization tolerance threshold; the terminal wireless device is corrected according to the time correction period.

2. The timekeeping method of claim 1, wherein, The power distribution network adopts a hierarchical networking manner and comprises multiple layers of nodes, the nodes in the power distribution network are connected through power line carrier communication links and / or wireless communication links; the multiple layers of nodes in the power distribution network comprise master nodes and slave nodes, the 0th layer of nodes in the power distribution network are master nodes, and the nodes of other layers except the 0th layer of nodes are slave nodes, the master nodes and the slave nodes are both provided with zero-crossing detection circuits, the upper layer node of the slave node comprises the master node, the master node is a specified node in the power distribution network or a node corrected through the specified node in the power distribution network; the correction of other nodes in the power distribution network based on the specified node comprises: after the upper layer node of the slave node completes the correction, a time calibration beacon sent by the upper layer node is received, the time calibration beacon comprises time correction information, the time correction information comprises a time value of a sending time point of the time calibration beacon and an NTB time difference between the sending time point and a first zero-crossing time point of a phase line where the upper layer node sending the time calibration beacon is located, the time value of the sending time point of the time calibration beacon is counted by a local clock of the upper layer node sending the time calibration beacon; acquiring an NTB time difference between a receiving time of the time calibration beacon and a second zero-crossing time of the phase line where the slave node is located; calibrating the slave node according to the time calibration information in the received time calibration beacon and the NTB time difference between the receiving time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located.

3. The timekeeping method of claim 1 or 2, wherein, The power distribution network adopts a hierarchical networking manner and includes multiple layers of nodes. The nodes in the power distribution network are connected through power line carrier communication links and / or wireless communication links. The multiple layers of nodes in the power distribution network include calibration nodes and calibrated nodes. The calibration nodes and the calibrated nodes are in the same layer, adjacent layers or cross layers, respectively. The calibration nodes include designated nodes in the power distribution network or nodes calibrated through the designated nodes in the power distribution network. The calibration of other nodes in the power distribution network based on the designated nodes includes: acquiring first calibration information, the first calibration information being a local clock timing value of the calibrated node acquired by the calibrated node at a reference time or a time having a preset relationship with the reference time; acquiring second calibration information, the second calibration information being a local clock timing value of the calibration node acquired by the calibration node at the reference time after completing calibration; calibrating the calibrated node based on the first calibration information and the second calibration information; The reference time is a time when the calibrated node and the calibration node simultaneously receive a reference beacon sent by a reference node. The calibration node and the calibrated node are each provided with a zero-crossing detection circuit. The reference time is a specified zero-crossing time. The specified zero-crossing time includes a rising edge zero-crossing time and / or a falling edge zero-crossing time.

4. The timekeeping method according to any one of claims 1 to 3, wherein, The calibration period of the end wireless device is acquired according to a time error coefficient of the end wireless device connected to the node and a maximum time synchronization tolerance threshold. obtain a time error coefficient of the terminal wireless device, and form a time error coefficient set Q α , denoted as: Q α ={α1,α2,…α n n}; wherein n represents the number of the terminal wireless devices, the time error coefficient α i of the i-th terminal wireless device is calculated based on a time interval T b between twice time correction of the i-th terminal wireless device by the node, and an internal clock time error Δt i of the i-th terminal wireless device after the twice time correction, and is calculated by the following formula: a i = Δt i / T b , where Δt i = |T i2 -T i1 |, T i1 is the internal clock time of the i-th end wireless device after the first time correction by the node, and T i2 is the internal clock time of the i-th end wireless device after the second time correction by the node. The maximum time synchronization tolerance threshold of the end wireless device is acquired. The maximum time synchronization tolerance threshold and the set of time error coefficients are used to calculate the maximum time synchronization period of the terminal wireless device, forming the maximum time synchronization period set {T}. MAX_1 ,T MAX_2 ,…T MAX_n }, where the maximum synchronization period T of the i-th terminal wireless device MAX_i =Δt MAX_i / α i , Δt MAX_i The maximum time synchronization tolerance threshold for the i-th terminal wireless device; The calibration period of the end wireless device is obtained through time slot allocation according to the maximum calibration period of the end wireless device.

5. The timekeeping method of claim 4, wherein, The end wireless device is calibrated according to the calibration period. Determination of optimization targets: wherein p c is the power consumption of the node for time synchronization of the end wireless device; Δt c is the channel time occupied by the node for time synchronization of the end wireless device, β T is a threshold value of the channel occupation ratio of the node for time synchronization of the end wireless device, T i is the time synchronization period of the i-th end wireless device; optimizing a time alignment period {T1, T2,... Tn} of the end wireless device according to the optimization target n} The end wireless device is calibrated according to the optimized calibration period.

6. A calibration method for a multi-source fusion node, the multi-source fusion node supporting fusion time calibration of multiple different time sources, the calibration method comprising: acquiring multiple time calibrations respectively from multiple different time sources; determining one or more first intermediate value sets according to the multiple time calibrations, the first intermediate value set being determined according to time calibrations from at least two different time sources; In a case where the first intermediate value set is multiple, the elements in the first intermediate value set are multiple, a corresponding multiple second intermediate values are determined according to the multiple first intermediate value sets respectively; wherein, for each first intermediate value set, the second intermediate value is determined according to the credibility of the time service source corresponding to the first intermediate value set, or according to the time service time deviation value between the time service sources corresponding to the first intermediate value set; a target second intermediate value is selected from the multiple second intermediate values according to a preset rule; the first intermediate value set corresponding to the target second intermediate value is used to time correct the specified node, and the specified node includes the multi-source fusion node or a node other than the multi-source fusion node; In a case where the first intermediate value set is one, the element in the first intermediate value set is one or more, and the first intermediate value set is used to time correct the specified node.

7. The timekeeping method of claim 6, wherein, The multiple time service times respectively from the multiple different time service sources are obtained, including: A preferred time service source set is obtained, the preferred time service source set includes multiple different preferred time service sources, and the preferred time service source is a time service source that meets an evaluation condition and is selected from the multiple different time service sources through evaluation; The multiple time service times respectively from the multiple different preferred time service sources are obtained based on the preferred time service source set.

8. The timekeeping method of claim 7, wherein, The preferred time service source set is determined according to the following manner: Time service source evaluation indexes of the multiple different time service sources are obtained, wherein the time service source evaluation indexes are used to evaluate the availability of a time service source; An utility function is constructed according to the time service source evaluation indexes, and utility values of the multiple different time service sources are calculated by using the utility function; The multiple different time service sources are sorted from high to low according to the utility values, and a preset number of time service sources are selected according to a sorting result to form the preferred time service source set.

9. The timekeeping method of claim 8, wherein, The time service source evaluation indexes include time service signal quality, time service precision, time service credibility and long-term availability; the utility function is constructed according to the time service source evaluation indexes, and the utility values of the multiple different time service sources are calculated by using the utility function, including: Time service signal strength and / or time service signal signal-to-noise ratio and / or time service signal jitter rate of each time service source are obtained, and scores of time service signal quality of each time service source are obtained according to the time service signal strength and / or time service signal signal-to-noise ratio and / or time service signal jitter of each time service source; Time service precision of each time service source is obtained, and scores of time service precision of each time service source are obtained according to the time service precision of each time service source; Time service credibility of each time service source is judged by comparing synchronization of time service time of each time service source and a time pulse signal, including: frequencies of time pulse signals of each time service source are monitored, pulse deviations of each time service source are calculated, and scores of time service credibility of each time service source are obtained according to the pulse deviations of each time service source; Available time of each time service source in a preset time period is counted, long-term availability of each time service source is obtained according to the available time of each time service source in the preset time period, and scores of long-term availability of each time service source are obtained according to the long-term availability of each time service source; A utility function is constructed according to the scores of the time service signal quality, the time service precision, the time service credibility and the long-term availability, and the utility value of each time service source is calculated according to the utility function: U i = a Q i + b P i + g R i + d A i ; wherein, U i represents the utility value of the i-th time service source, Q i represents the score of the time service signal quality of the i-th time service source, and a represents the weight of the time service signal quality of the i-th time service source; P i represents the score of the time service accuracy of the i-th time service source, and β represents the weight of the time service accuracy of the i-th time service source; R i represents the score of the time service reliability of the i-th time service source, and γ represents the weight of the time service reliability of the i-th time service source; A i represents the score of the long-term availability of the i-th time service source, and δ represents the weight of the long-term availability of the i-th time service source.

10. A timekeeping method according to claim 8 or 9, wherein, The time service source evaluation index of the plurality of different time service sources is acquired, including: The current time service mode is acquired, including one of a normal time service mode, an emergency time service mode, a high-precision time service mode, a regional time service mode and a backup time service mode; The time service source evaluation index of the plurality of different time service sources in the current time service mode is acquired.

11. A timekeeping method according to any one of claims 6 to 10, wherein, The first intermediate value set is determined according to the plurality of time service times, including: The time service precision and the comprehensive credibility of each time service source are acquired, wherein the comprehensive credibility is determined based on the stability parameter, the accuracy parameter and the environmental factor of the corresponding time service source; The time service precision interval of each time service source is determined according to the time service precision of each time service source; The credibility density of each time service source is determined according to the time service precision interval and the comprehensive credibility of each time service source, and the credibility density is the comprehensive credibility divided by the length of the time service precision interval; The credibility density of each time service source is normalized; The multi-source fusion time service time is calculated according to the time service time of each time service source and the normalized credibility density of each time service source, and the multi-source fusion time service time forms the first intermediate value set.

12. The timekeeping method of claim 11, wherein, The multi-source fusion time service time is calculated according to the time service time of each time service source and the normalized credibility density of each time service source, including: The multi-source fusion time t is calculated by using the following formula d : wherein t i is the time of the i-th time service; d i is the normalized trust density of the i-th time service, n is the total number of the time service sources; The first intermediate value set is used to time correct the specified node by the following method, including: The specified node is time corrected by the multi-source fusion time service time.

13. A timekeeping method according to any one of claims 7 to 9, wherein, The one or more first intermediate value sets are determined according to the plurality of time service times, including: The time service precision of each preferred time service source is acquired; The time service range interval of each preferred time service source is determined according to the time service precision and the time service time of each preferred time service source; The intersection interval is formed by comparing the time service range interval of each preferred time service source, and the two interval endpoints of the intersection interval form the first intermediate value set.

14. The timekeeping method of claim 13, wherein, In the case that the first intermediate value set is one, the first intermediate value set is used to time correct the specified node by the following method, including: The average value of the two interval endpoints in the first intermediate value set is taken as the multi-source fusion time service time, and the specified node is time corrected by the multi-source fusion time service time; In the case that the first intermediate value set is multiple, the corresponding multiple second intermediate values are determined according to the multiple first intermediate value sets, including: The second intermediate value corresponding to each first intermediate value set is determined in the following manner: The time service precision interval of each preferred time service source corresponding to the first intermediate value set is determined according to the time service precision of each preferred time service source corresponding to the first intermediate value set; The credibility density of each preferred time service source corresponding to the first intermediate value set is determined according to the credibility and the time service precision interval of each preferred time service source corresponding to the first intermediate value set, and the credibility density is the credibility divided by the length of the time service precision interval; The second intermediate value corresponding to the first intermediate value set is determined according to the maximum of the trust density of each preferred time source corresponding to the first intermediate value set and the length of the intersection interval corresponding to the first intermediate value set, and the second intermediate value is the product of the maximum and the length of the intersection interval.

15. The timekeeping method of claim 14, wherein, The method further comprises: selecting the maximum of the plurality of second intermediate values as the target second intermediate value; The first intermediate value set corresponding to the target second intermediate value is used to calibrate the specified node in the following manner: The average value of the two interval endpoints in the first intermediate value set corresponding to the target second intermediate value is taken as a multi-source fusion time, and the specified node is calibrated using the multi-source fusion time.

16. A timekeeping method according to any one of claims 7 to 9, wherein, The method further comprises: monitoring the availability of each preferred time source in the set of preferred time sources; In the case where the number of preferred time sources with availability in the set of preferred time sources does not satisfy a preset number threshold, the set of preferred time sources is re-determined.

17. The timekeeping method of claim 16, wherein, The method further comprises: performing least squares estimation on the local clock error of the multi-source fusion node after calibration to generate a first error compensation parameter p1 and a second error compensation parameter p2; According to the running values t i-2 , t i-1 , t i at the i-2, i-1 and i instants respectively corresponding to the local clock of the multi-source fusion node and the first error compensation parameter p1 and the second error compensation parameter p2, the time at the i instant of the local clock of the multi-source fusion node for which the prediction compensation is obtained wherein obtaining the time service time of each preferred time service source in the set of preferred time service sources at the i moment, respectively denoted as: t i1 ,t i2 ,…t in ; n represents the number of preferred time service sources in the set of preferred time service sources; errors between the time of the time service of each preferred time service source i at time instant i in the set of preferred time service sources and the time of the local clock of the multi-source fusion node with prediction compensation at time instant i, wherein the time of the time service of the jth preferred time service source at time instant i is denoted as ij errors between the time of the time service of each preferred time service source i at time instant i in the set of preferred time service sources and the time of the local clock of the multi-source fusion node with prediction compensation at time instant i, wherein the time of the time service of the jth preferred time service source at time instant i is denoted as 0j errors between the time of the time service of each preferred time service source i at time instant i in the set of preferred time service sources and the time of the local clock of the multi-source fusion node with prediction compensation at time instant i, wherein the time of the time service of the jth preferred time service source at time instant i is denoted as determining whether each error is greater than a set error threshold, and if so, determining that the corresponding preferred time source does not have availability, and deleting the corresponding preferred time source from the set of preferred time sources.

18. A timekeeping method according to any one of claims 6 to 17, wherein, The multi-source fusion node is in a first mobile communication network, and the plurality of different time sources supported by the multi-source fusion node includes a mobile communication air interface time source and a preset reference time source. The method further comprises: obtaining the time of the preset reference time source corresponding to n historical time points to form a first time sequence; n is a positive integer greater than a preset threshold; obtaining the time of the mobile communication air interface time source corresponding to the n historical time points to form a second time sequence; The method further comprises: calculating the time deviation value between the first time sequence and the second time sequence corresponding to each historical time point to form an original time deviation value sequence; wherein the filtered time bias value sequence corresponding to the window length value is determined in the following way: wherein ΔT i represents the i th sequence value in the filtered time bias value sequence, m represents the window length value, and ΔT i-j represents the i th sequence value in the filtered time bias value sequence, m represents the window length value, and ΔT 19. The timekeeping method of claim 18, wherein, performing moving average filtering processing on the original time deviation value sequence based on each window length value in a plurality of preset window length values to generate a plurality of filtered time deviation value sequences corresponding to the plurality of window length values, respectively; the filtered time deviation value sequences form the first intermediate value set; The method further comprises: According to the original time service time bias value sequence and the filtered time service time bias value sequence corresponding to the first intermediate value set, a Pearson coefficient p is calculated, the Pearson coefficient p is a second intermediate value corresponding to the first intermediate value set, and the Pearson coefficient p is expressed by the following formula: where ΔT i denotes the i-th sequence value in the original time bias value sequence, and a mean of the original and filtered sequences of time bias values, respectively, is a covariance of the original time bias value sequence and the filtered time bias value sequence, and determining the second intermediate value corresponding to each first intermediate value set in the following manner:

20. The timekeeping method of claim 19, wherein, The standard deviations of the original time deviation value sequence and the filtered time deviation value sequence, respectively. The method further comprises: The plurality of Pearson coefficients corresponding to the plurality of window length values are compared with a preset Pearson coefficient threshold value respectively, and a Pearson coefficient in the plurality of Pearson coefficients that is closest to the preset Pearson coefficient threshold value is taken as the target second intermediate value.

21. The timekeeping method of claim 20, wherein, The first intermediate value set corresponding to the target second intermediate value is used to time the specified node by: determine a timing time optimization parameter based on an n th sequence value in the filtered timing time deviation value sequence corresponding to the target second intermediate value and an air interface transmission delay corresponding to the n th historical time of the mobile communication air interface timing source, wherein the timing time optimization parameter η n is expressed as follows: wherein ΔT n is the nth filtered time bias value, τ n is the air interface transmission delay corresponding to the nth historical time. correcting the time of the mobile communication air interface time source using the time of the time optimization parameter, and using the time of the time optimization parameter of the corrected mobile communication air interface time source to time the specified node.

22. The timekeeping method of claim 21, wherein, The use of the time of the time optimization parameter to correct the time of the mobile communication air interface time source includes: obtaining the reference time and the time advance (TA) sent by the mobile communication air interface time source; determining the current air interface transmission delay according to the time advance (TA); the sum of the current air interface transmission delay and the reference time sent by the mobile communication air interface time source is taken as the time of the mobile communication air interface time source; based on the time of the time optimization parameter, the time of the mobile communication air interface time source is corrected using the following formula: t r = t0+ τ x (1+ η n ), Wherein, t r is the timing time of the corrected mobile communication air interface timing source, t0 is the reference time sent by the mobile communication air interface timing source, and τ is the current air interface transmission delay.

23. A timekeeping method according to claim 21 or 22, wherein, The specified node includes a mobile communication time node, which is in the first mobile communication network or the second mobile communication network, and supports the mobile communication air interface time source; the use of the time of the time optimization parameter to correct the time of the mobile communication air interface time source includes: sending the time of the time optimization parameter to the mobile communication base station of the first mobile communication network, so that the mobile communication base station in the first mobile communication network carries the time of the time optimization parameter to time the mobile communication time node in the first mobile communication network, so that the mobile communication time node in the first mobile communication network corrects the time of the mobile communication air interface time source using the time of the time optimization parameter; and / or, so that the mobile communication base station of the first mobile communication network returns the time of the time optimization parameter to the mobile communication access layer network, so that the mobile communication access layer network issues the time of the time optimization parameter to the mobile communication base station in the second mobile communication network, so that the mobile communication base station in the second mobile communication network carries the time of the time optimization parameter to time the mobile communication time node in the second mobile communication network, so that the mobile communication time node in the second mobile communication network corrects the time of the mobile communication air interface time source using the time of the time optimization parameter.

24. The timekeeping method of claim 23, wherein, In the case where the first mobile communication network includes a plurality of multi-source fusion nodes, the time correction method further includes: sending a plurality of time optimization parameters respectively determined by the plurality of multi-source fusion nodes to the mobile communication base station in the first mobile communication network, so that the mobile communication base station in the first mobile communication network determines a final time optimization parameter according to the plurality of time optimization parameters; receive a plurality of timing time optimization parameters corresponding to the plurality of multi-source fusion nodes from a mobile communication base station of the first mobile communication network; correct the timing time of the mobile communication air interface timing source using the plurality of timing time optimization parameters respectively, obtain a plurality of corrected timing times of the mobile communication air interface timing source corresponding to the plurality of timing time optimization parameters, calculate a plurality of errors corresponding to the plurality of timing time optimization parameters respectively by calculating the difference between the plurality of corrected timing times of the mobile communication air interface timing source and the timing time of the preset reference timing source, and send the plurality of errors corresponding to the plurality of timing time optimization parameters to the mobile communication base station of the first mobile communication network, so that after the mobile communication base station of the first mobile communication network receives the plurality of errors corresponding to the plurality of timing time optimization parameters sent by each multi-source fusion node, the mobile communication base station of the first mobile communication network performs weighted average on each error calculated by the plurality of multi-source fusion nodes using the same timing time optimization parameter to obtain a plurality of weighted average results, and sends the timing time optimization parameter of the multi-source fusion node corresponding to the minimum weighted average result in the plurality of weighted average results as the final timing time optimization parameter to the plurality of multi-source fusion nodes; receive the final timing time optimization parameter sent by the mobile communication base station of the first mobile communication network, so as to correct the timing time of the mobile communication air interface timing source using the final timing time optimization parameter.

25. A timekeeping method according to any one of claims 6 to 24, wherein, The multi-source fusion node is in a first mobile communication network, a plurality of different timing sources supported by the multi-source fusion node include a mobile communication air interface timing source and a preset reference timing source, the mobile communication air interface timing source includes a cellular communication air interface timing and a direct communication timing, the first mobile communication network further includes a non-cellular timing node, the non-cellular timing node does not support cellular communication air interface timing and supports direct communication timing, the specified node is connected with the non-cellular timing node through a direct communication link, and the time correction method further includes: After the specified node is time-corrected, the non-cellular timing node and the specified node interact with each other through a precision time protocol (PTP) to measure delay information, so that the non-cellular timing node performs time synchronization based on the specified node.

26. A time correction method for a power utilization network, the power utilization network adopts a hierarchical networking manner and includes a plurality of layers of nodes, a 0th layer node is a master node, and other layer nodes except the 0th layer node are slave nodes, the slave nodes are connected with upper layer nodes through power line carrier communication links and / or wireless communication links, the master node and the slave nodes are both provided with zero-crossing detection circuits, the time correction method is applied to a slave node in the power utilization network, and the time correction method includes: receive a time calibration beacon sent by an upper node of the slave node after the upper node completes time calibration, the time calibration beacon containing time calibration information, the time calibration information including a time value of a sending time of the time calibration beacon and an NTB time difference between the sending time and a first zero-crossing time of a phase line where the upper node is located, the time value of the sending time of the time calibration beacon being counted by a local clock of the upper node; obtain an NTB time difference between a receiving time of the time calibration beacon and a second zero-crossing time of a phase line where the slave node is located; calibrate the slave node according to the time calibration information in the received time calibration beacon and the NTB time difference between the receiving time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located. The upper node of the slave node includes the master node, the master node being a designated node in the power utilization network or a node that is calibrated by the designated node, the designated node including a multi-source fusion node or a node other than the multi-source fusion node, the multi-source fusion node supporting multi-source time service fusion, and the designated node being calibrated by the multi-source fusion node in the following manner: obtain multiple time services respectively from multiple different time service sources; determine one or more first intermediate value sets according to the multiple time services, the first intermediate value set being determined according to time services from at least two different time service sources; in a case where the first intermediate value set is multiple, the elements in the first intermediate value set are multiple, a corresponding multiple second intermediate values are determined according to the multiple first intermediate value sets, respectively; for each first intermediate value set, the second intermediate value is determined according to a credibility of a time service source corresponding to the first intermediate value set or according to a time service time deviation value between time services of the time service source corresponding to the first intermediate value set, a target second intermediate value is selected from the multiple second intermediate values according to a preset rule, and the designated node is calibrated according to a first intermediate value set corresponding to the target second intermediate value; in a case where the first intermediate value set is one, the element in the first intermediate value set is one or more, and the designated node is calibrated according to the first intermediate value set.

27. The time calibration method according to claim 26, wherein: the first zero-crossing time and the second zero-crossing time are the same zero-crossing time; or the first zero-crossing time and the second zero-crossing time have a preset relationship.

28. A timekeeping method according to claim 26 or 27, wherein, The slave node is also connected to a lower node through a power line carrier communication link and / or a wireless communication link, and the time calibration method further includes: after the slave node completes time calibration, sending a time calibration beacon to the lower node, so that the lower node calibrates a local time according to time calibration information in the received time calibration beacon.

29. A timekeeping method according to any one of claims 26 to 28, wherein, The time calibration of the slave node according to the time calibration information in the received time calibration beacon and the NTB time difference between the time when the time calibration beacon is received and the second zero-crossing time of the phase line where the slave node is located comprises: obtaining a time calibration NTB time difference according to the NTB time difference in the time calibration information, the time calibration NTB time difference corresponding to the phase line where the slave node is located; calculating a time calibration beacon transmission delay time according to the time calibration NTB time difference and the NTB time difference between the time when the time calibration beacon is received and the second zero-crossing time of the phase line where the slave node is located; calculating a calibration time corresponding to the time when the time calibration beacon is received according to the time calibration beacon transmission delay time and the time value of the time when the time calibration information is sent; calibrating the time using the calibration time corresponding to the time when the time calibration beacon is received.

30. The timekeeping method of claim 29, wherein, Wherein, The NTB time difference comprises any one or more of a first NTB time difference, a second NTB time difference and a third NTB time difference; the first NTB time difference, the second NTB time difference and the third NTB time difference correspond to three different phase lines respectively, and the obtaining of the time calibration NTB time difference according to the NTB time difference in the time calibration information comprises: in the case where the NTB time difference in the time calibration information comprises the first NTB time difference, the second NTB time difference and the third NTB time difference, taking the NTB time difference corresponding to the phase line where the slave node is located in the NTB time difference in the time calibration information as the time calibration NTB time difference; in the case where the NTB time difference in the time calibration information is any one of the first NTB time difference, the second NTB time difference and the third NTB time difference, and the upper node sending the time calibration beacon and the slave node are homophase nodes, taking the NTB time difference in the time calibration information as the time calibration NTB time difference; in the case where the NTB time difference in the time calibration information is any one of the first NTB time difference, the NTB time difference and the third NTB time difference, and the upper node sending the time correction beacon and the slave node are non-homophase nodes, obtaining two NTB time differences respectively corresponding to the phase line where the slave node is located and the phase line where the upper node sending the time calibration beacon is located in the time calibration beacon sent by the master node, obtaining the difference between the two NTB time differences, and subtracting the difference from the NTB time difference in the time calibration information to obtain the time calibration NTB time difference.

31. A timekeeping method according to claim 29 or 30, wherein, The time calibration beacon transmission delay time is calculated using the following equation: T Intv = ΔT NTB-L + nT ABC - ΔT NTB ; The calibration time corresponding to the time when the time calibration beacon is received is calculated using the following formula: T P = T Intv + T c ; wherein, T P represents a calibration time corresponding to the time of receiving the time calibration beacon; T Intv represents a time delay of transmitting the time calibration beacon; T c represents a time value of the time of sending in the time calibration information; ΔT NTB-L represents an NTB time difference between the time of receiving the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located; T ABC is a power frequency cycle; n is a number of power frequency cycles crossed when the time calibration beacon is transmitted, n≥0, ΔT NTB is the time calibration NTB time difference.

32. A time synchronisation method for a power distribution network, wherein, The power utilization network adopts a hierarchical networking mode and comprises multiple layers of nodes, the 0th layer of nodes being master nodes, and other layers of nodes being slave nodes except for the 0th layer of nodes, the master nodes being connected with lower layer slave nodes through power line carrier communication links and / or wireless communication links, the master nodes and the slave nodes being provided with zero-crossing detection circuits, and the time calibration method being applied to the master nodes in the power utilization network, the time calibration method comprising: After the time correction is completed, a time calibration beacon is sent to the lower layer slave node to realize time correction of the lower layer slave node; the time calibration beacon contains time correction information, so that the lower layer slave node corrects local time according to the time correction information in the time calibration beacon and an NTB time difference between a time when the time calibration beacon is received and a zero-crossing time of a phase line where the lower layer slave node is located; wherein the time correction information includes a time value of a time when the time calibration beacon is sent and an NTB time difference between the time when the time calibration beacon is sent and a zero-crossing time of a phase line where the master node is located, and the time value of the time when the time calibration beacon is sent is counted by a local clock of the master node; Wherein, the master node is a designated node in the power distribution network, or a node that is time-corrected through the designated node, the designated node includes a multi-source fusion node or a node other than the multi-source fusion node, the multi-source fusion node supports multi-source time service fusion time service, and through the multi-source fusion node, the designated node in the power distribution network is time-corrected in the following way: Obtain multiple time service times respectively from multiple different time service sources; Determine one or more first intermediate value sets according to the multiple time service times, the first intermediate value set being determined according to time service times from at least two different time service sources; In the case of multiple first intermediate value sets, the elements in the first intermediate value set are multiple, and a corresponding multiple second intermediate values are determined according to the multiple first intermediate value sets; wherein, for each first intermediate value set, the second intermediate value is determined according to the credibility of the time service source corresponding to the first intermediate value set, or according to the time service time deviation value between the time service times of the time service source corresponding to the first intermediate value set; a target second intermediate value is selected from the multiple second intermediate values according to a preset rule; and the designated node is time-corrected according to the first intermediate value set corresponding to the target second intermediate value; In the case of one first intermediate value set, the element in the first intermediate value set is one or more, and the designated node is time-corrected according to the first intermediate value set.

33. A time correction method for a power distribution network, the power distribution network adopting a hierarchical networking manner and including multiple layers of nodes, time correction nodes and time-corrected nodes being in the same layer, adjacent layers or across layers, and being connected through power line carrier communication links and / or wireless communication links, the time correction method being applied to a time-corrected node in the power distribution network, and the time correction method comprising: obtaining first time correction information, the first time correction information being a local clock timing value of the time-corrected node obtained at a reference time or a time having a preset relationship with the reference time; obtaining second time correction information, the second time correction information being a local clock timing value of the time correction node obtained at the reference time after the time correction is completed; time-correcting the time-corrected node based on the first time correction information and the second time correction information. The reference time instant is a time instant when the to-be-corrected node and the time-corrected node simultaneously receive a reference beacon sent by a reference node; and / or, the reference time instant is a specified zero-crossing time instant, and the specified zero-crossing time instant includes a rising edge zero-crossing time instant and / or a falling edge zero-crossing time instant; The time-corrected node is a specified node in the power utilization network or a node that is time-corrected through the specified node, and the specified node includes a multi-source fusion node or a node other than the multi-source fusion node. The multi-source fusion node supports multi-source time service fusion, and the specified node in the power utilization network is time-corrected through the multi-source fusion node in the following manner: Obtaining a plurality of time services respectively from a plurality of different time service sources; Determining one or more first intermediate value sets according to the plurality of time services, wherein the first intermediate value set is determined according to time services from at least two different time service sources; In the case where the first intermediate value set is a plurality, the elements in the first intermediate value set are a plurality, a plurality of second intermediate values are determined according to the plurality of first intermediate value sets respectively; wherein, for each first intermediate value set, the second intermediate value is determined according to the credibility of the time service source corresponding to the first intermediate value set, or according to the time service time deviation value between the time services of the time service source corresponding to the first intermediate value set; a target second intermediate value is selected from the plurality of second intermediate values according to a preset rule; and the specified node is time-corrected according to the first intermediate value set corresponding to the target second intermediate value. In the case where the first intermediate value set is one, the element in the first intermediate value set is one or more, and the specified node is time-corrected according to the first intermediate value set.

34. The timekeeping method of claim 33, wherein, In the case where the reference time instant is a specified zero-crossing time instant, the first time correction information is a time value recorded by a phase line on which the to-be-corrected node is located with a local clock at one or more specified zero-crossing time instants; and the second time correction information is a time value recorded by a phase line on which the time-corrected node is located with a local clock at one or more specified zero-crossing time instants. In the case where the reference time instant is a time instant when the to-be-corrected node and the time-corrected node simultaneously receive a reference beacon sent by a reference node, the physical layer of the time-corrected node, the to-be-corrected node and the reference node has the same transceiving delay in the same communication mode, and the first time correction information and the second time correction information are respectively time values recorded by the to-be-corrected node and the time-corrected node with a local clock when they simultaneously receive a reference beacon sent by the same reference node.

35. A timekeeping method according to claim 33 or 34, wherein, The obtaining of the second time correction information includes: Receiving a time calibration beacon sent by the time-corrected node, wherein the time calibration beacon carries the second time correction information; and obtaining the second time correction information from the time calibration beacon.

36. The timekeeping method of claim 35, wherein, When the time calibration beacon sent by the time-corrected node is received, the time correction method further includes: record a calibration timestamp value, which is a time value recorded by the calibrated time node in a local clock corresponding to a moment when the time calibration beacon is received; the time calibration of the calibrated time node based on the first time calibration information and the second time calibration information comprises: time calibration of the calibrated time node based on the first time calibration information, the second time calibration information and the calibration timestamp value using the following formula: ts r = tr r - (tt r - tt t ); tt r represents the first time information, tt t represents the second time information, tr r represents the calibration timestamp value, ts r represents the local clock time value of the time-synchronized node after the calibration timestamp value is time-synchronized.

37. A timekeeping method according to claim 35 or 36, wherein, In the case of receiving time calibration beacons sent by multiple time calibration nodes, the time calibration information in the time calibration beacon sent by the time calibration node closest to the communication distance or having the best communication quality or the lowest level among the multiple time calibration nodes is selected as the second time calibration information.

38. A timekeeping method according to any one of claims 35 to 37, wherein, If multiple time calibration nodes send time calibration beacons, the multiple time calibration nodes include: a first time calibration node and a second time calibration node; the time calibration of the calibrated time node based on the first time calibration information and the second time calibration information comprises: In the case that the first time calibration node is closest to the communication distance or has the lowest level relative to the second time calibration node and the calibrated time node, the time calibration of the calibrated time node is based on the second time calibration information of the first time calibration node and the first time calibration information; In the case that the first time calibration node and the second time calibration node are at the same level, the signal quality indicators when the first time calibration node and the second time calibration node communicate with the source node of the previous layer are obtained respectively, the corresponding communication quality is evaluated according to the signal quality indicators, and the time calibration node that meets the evaluation condition is selected from the first time calibration node and the second time calibration node according to the communication quality evaluation result; the time calibration of the calibrated time node is based on the second time calibration information of the time calibration node that meets the evaluation condition and the first time calibration information.

39. A timekeeping method according to any one of claims 33 to 38, wherein, The time calibration method further comprises: least square estimation of the local clock error of the calibrated time node after multiple time calibrations to generate a first error compensation parameter p1 and a second error compensation parameter p2; from the running values t i-2 , t i-1 , t i and the first error compensation parameter p1 and the second error compensation parameter p2 determine the time of the i-th instant of the local clock of the disciplined node predicted compensated wherein 40. A timekeeping method according to any one of claims 33 to 39, wherein, In the case that the reference moment is a specified zero-crossing moment, the time calibration of the calibrated time node based on the first time calibration information and the second time calibration information comprises: According to the first time calibration information and the second time calibration information, the time deviation of the time calibration node and the calibrated time node corresponding to the same phase line and the same voltage waveform period at the specified zero-crossing moment is obtained in the local clock; The calibrated time node is time calibrated using the time deviation.

41. The timekeeping method of claim 40, wherein, According to the first time calibration information and the second time calibration information, the time deviation of the time calibration node and the calibrated time node corresponding to the same phase line and the same voltage waveform period at the specified zero-crossing moment is obtained, comprising: In the case that the calibrated time node is on the same phase line as the time calibration node, the time value of the specified zero-crossing moment in the same voltage waveform period corresponding to the first time calibration information in the second time calibration information is obtained; In the case that the calibrated time node is on the same phase line as the time calibration node, the time value of the specified zero-crossing moment in the same voltage waveform period corresponding to the first time calibration information in the second time calibration information is obtained; In the case that the to-be-synchronized node is on a different phase line from the synchronized node, a phase difference between the to-be-synchronized node and the phase line where the synchronized node is located is obtained, and a time value of the specified zero-crossing moment in a same voltage waveform period of a same phase line corresponding to the first synchronization information is obtained according to the phase difference, as the second synchronization information; In the case that the synchronized node is on multiple phase lines, a time value of the specified zero-crossing moment in a same voltage waveform period of a same phase line corresponding to the first synchronization information is obtained according to a time value of the specified zero-crossing moment in the first synchronization information corresponding to the phase line where the synchronized node is located, as the second synchronization information; A time deviation of the specified zero-crossing moment in a same voltage waveform period corresponding to the first synchronization information and the second synchronization information is calculated.

42. The timekeeping method of claim 41, wherein, If the specified zero-crossing moment is multiple, the synchronization method further comprises: An average value of the time deviation of the specified zero-crossing moment in the first synchronization information and the second synchronization information is calculated, and the to-be-synchronized node is synchronized by using the average value of the time deviation.

43. A time synchronisation method for a power distribution network, wherein, The power distribution and utilization network adopts a hierarchical networking manner and comprises multiple layers of nodes, the synchronized node and the to-be-synchronized node are on a same layer, adjacent layers or cross layers, and are connected through a power line carrier communication link and / or a wireless communication link, and the synchronization method is applied to the synchronized node in the power distribution and utilization network, and the synchronization method comprises: After synchronization is completed, second synchronization information is generated; The second synchronization information is sent to the to-be-synchronized node, so that the to-be-synchronized node obtains the second synchronization information and synchronizes the to-be-synchronized node based on the first synchronization information and the obtained second synchronization information; the first synchronization information is a local clock timing value of the to-be-synchronized node obtained at a reference time or a time having a preset relationship with the reference time, and the second synchronization information is a local clock timing value of the synchronized node obtained at the reference time after synchronization is completed; The reference time is a time at which the to-be-synchronized node and the synchronized node simultaneously receive a reference beacon sent by a reference node; and / or, a zero-crossing detection circuit is arranged in the synchronized node and the to-be-synchronized node, the reference time is a specified zero-crossing moment, and the specified zero-crossing moment comprises a rising edge zero-crossing moment and / or a falling edge zero-crossing moment; The synchronized node is a specified node in the power distribution and utilization network or a node synchronized through the specified node, the specified node comprises a multi-source fusion node or a node other than the multi-source fusion node, the multi-source fusion node supports multi-source time service fusion, and the specified node in the power distribution and utilization network is synchronized through the multi-source fusion node in the following manner: A plurality of time services respectively from a plurality of different time service sources are obtained; One or more first intermediate value sets are determined according to the plurality of time services, and the first intermediate value set is determined according to time services from at least two different time service sources; In a case where the first intermediate value set is multiple, the elements in the first intermediate value set are multiple, and a corresponding multiple second intermediate values are determined according to the multiple first intermediate value sets respectively; wherein, for each first intermediate value set, the second intermediate value is determined according to the credibility of the time service source corresponding to the first intermediate value set, or according to a time service deviation value between the time service time of the time service source corresponding to the first intermediate value set; a target second intermediate value is selected from the multiple second intermediate values according to a preset rule; and the specified node is time-synchronized according to the first intermediate value set corresponding to the target second intermediate value; In a case where the first intermediate value set is one, the element in the first intermediate value set is one or more, and the specified node is time-synchronized according to the first intermediate value set.

44. The timekeeping method of claim 43, wherein, The sending of the second time-synchronization information to the time-synchronized node includes: Sending a time calibration beacon to the time-synchronized node directly or through a relay node, and the time calibration beacon carries the second time-synchronization information.

45. A timekeeping device for a power distribution network, wherein, The power distribution and utilization network adopts a hierarchical networking manner and includes multiple layers of nodes, the time-synchronized node and the time-synchronized node are in the same layer, adjacent layers or cross layers, are connected through a power line carrier communication link and / or a wireless communication link, and the time-synchronization device is arranged in the time-synchronized node in the power distribution and utilization network, and the time-synchronization device includes: A first time-synchronization information acquisition module configured to acquire first time-synchronization information, the first time-synchronization information being a local clock timing value of the time-synchronized node acquired at a reference time or a time having a preset relationship with the reference time; A second time-synchronization information acquisition module configured to acquire second time-synchronization information, the second time-synchronization information being a local clock timing value of the time-synchronized node acquired at the reference time after time-synchronization is completed; A first time-synchronization module configured to time-synchronize the time-synchronized node based on the first time-synchronization information and the second time-synchronization information; The reference time is a time at which the time-synchronized node and the time-synchronized node simultaneously receive a reference beacon sent by a reference node; and / or, a zero-crossing detection circuit is arranged in each of the time-synchronized node and the time-synchronized node, and the reference time is a specified zero-crossing time, and the specified zero-crossing time includes a rising edge zero-crossing time and / or a falling edge zero-crossing time; The time-synchronized node is a specified node in the power distribution and utilization network or a node time-synchronized through the specified node, and the specified node includes a multi-source fusion node or a node other than the multi-source fusion node, the multi-source fusion node supports multi-source time service fusion, and the specified node in the power distribution and utilization network is time-synchronized through the multi-source fusion node in the following manner: Multiple time service times respectively from multiple different time service sources are acquired; One or more first intermediate value sets are determined according to the multiple time service times, and the first intermediate value set is determined according to time service times from at least two different time service sources; In a case where the first intermediate value set is multiple, the elements in the first intermediate value set are multiple, and a corresponding multiple second intermediate values are determined according to the multiple first intermediate value sets respectively; wherein, for each first intermediate value set, the second intermediate value is determined according to the credibility of the time service source corresponding to the first intermediate value set, or according to the time service time deviation value between the time service time of the time service source corresponding to the first intermediate value set; a target second intermediate value is selected from the multiple second intermediate values according to a preset rule; and the multi-source fusion node is time-synchronized according to the first intermediate value set corresponding to the target second intermediate value; In a case where the first intermediate value set is one, the element in the first intermediate value set is one or more, and the multi-source fusion node is time-synchronized according to the first intermediate value set.

46. The timekeeping device of claim 45, wherein, The time-synchronization device further comprises: The clock self-maintenance module is configured to perform least square estimation on the local clock error after multiple time corrections to generate a first error compensation parameter p1 and a second error compensation parameter p2; determine a predicted compensated time of the local clock i moment according to the running values t i-2 、t i-1 、t i corresponding to the local clock i-2, i-1 and i moments respectively and the first error compensation parameter p1 and the second error compensation parameter p2 wherein 47. A timekeeping device for a power distribution network, wherein, The power distribution and utilization network adopts a hierarchical networking manner and comprises multiple layers of nodes, the time-synchronization node and the time-synchronized node are in the same layer, adjacent layers or cross layers, and are connected through a power line carrier communication link and / or a wireless communication link, the time-synchronization device is arranged in the time-synchronized node in the power distribution and utilization network, and the time-synchronization device comprises: A first time-synchronization information generation module configured to generate second time-synchronization information after time-synchronization is completed; A first time-synchronization information sending module configured to send the second time-synchronization information to the time-synchronized node, so that the time-synchronized node acquires the second time-synchronization information and time-synchronizes the time-synchronized node based on the first time-synchronization information and the acquired second time-synchronization information; the first time-synchronization information is a local clock timing value of the time-synchronized node acquired by the time-synchronized node at a reference time or a time having a preset relationship with the reference time, and the second time-synchronization information is a local clock timing value of the time-synchronized node acquired by the time-synchronized node at the reference time after time-synchronization is completed; The reference time is a time at which the time-synchronized node and the time-synchronized node simultaneously receive a reference beacon sent by a reference node; and / or, a zero-crossing detection circuit is arranged in each of the time-synchronized node and the time-synchronized node, and the reference time is a specified zero-crossing time, and the specified zero-crossing time comprises a rising edge zero-crossing time and / or a falling edge zero-crossing time; The time-synchronized node is a specified node in the power distribution and utilization network or a node time-synchronized through the specified node, and the specified node comprises a multi-source fusion node or a node other than the multi-source fusion node, the multi-source fusion node supports multi-source fusion time service of multiple different time service sources, and the multi-source fusion node is used to time-synchronize the specified node in the power distribution and utilization network in the following manner: Multiple time service times respectively from multiple different time service sources are acquired; One or more first intermediate value sets are determined according to the multiple time service times, and the first intermediate value set is determined according to the time service time from at least two different time service sources; In a case where the first intermediate value set is multiple, the elements in the first intermediate value set are multiple, and a plurality of second intermediate values corresponding to the plurality of first intermediate value sets are determined respectively; wherein, for each first intermediate value set, the second intermediate value is determined according to the credibility of the time service source corresponding to the first intermediate value set, or according to the time service time deviation value between the time service time of the time service source corresponding to the first intermediate value set; a target second intermediate value is selected from the plurality of second intermediate values according to a preset rule; and the specified node is time-synchronized according to the first intermediate value set corresponding to the target second intermediate value; In a case where the first intermediate value set is one, the element in the first intermediate value set is one or more, and the specified node is time-synchronized according to the first intermediate value set.

48. A timekeeping apparatus for a multi-source fusion node, wherein, The multi-source fusion node supports fusion time service of a plurality of different time service sources, and the time-synchronization device comprises a multi-source time service time acquisition module and a multi-source time service fusion module. The multi-source time service time acquisition module is configured to acquire a plurality of time service times respectively from a plurality of different time service sources. The multi-source time service fusion module is configured to determine one or more first intermediate value sets according to the plurality of time service times, the first intermediate value set being determined according to time service times from at least two different time service sources; in a case where the first intermediate value set is multiple, the elements in the first intermediate value set being multiple, a plurality of second intermediate values corresponding to the plurality of first intermediate value sets are determined respectively; for each first intermediate value set, the second intermediate value is determined according to the credibility of the corresponding time service source, or according to the time service time deviation value between the time service time of the corresponding time service source; a target second intermediate value is selected from the plurality of second intermediate values according to a preset rules; and the first intermediate value set corresponding to the target second intermediate value is used to time-synchronize a specified node, the specified node comprising the multi-source fusion node or a node other than the multi-source fusion node; in a case where the first intermediate value set is one, the element in the first intermediate value set being one or more, the first intermediate value set being used to time-synchronize the specified node.

49. The timekeeping device of claim 48, wherein, The acquisition of the plurality of time service times respectively from a plurality of different time service sources comprises: Acquiring a preferred time service source set, the preferred time service source set comprising a plurality of different preferred time service sources, the preferred time service source being a time service source that meets an evaluation condition and is selected from the plurality of different time service sources through evaluation; Based on the preferred time service source set, a plurality of time service times respectively from the plurality of different preferred time service sources are acquired.

50. The timekeeping device of claim 49, wherein, The time-synchronization device further comprises: A time service error monitoring module configured to monitor the availability of each preferred time service source in the preferred time service source set; in a case where the number of preferred time service sources that are available in the preferred time service source set does not meet a preset number threshold, the preferred time service source set is re-determined.

51. A timekeeping device for a power distribution network, wherein, The power distribution network adopts a hierarchical networking mode and comprises multiple layers of nodes, a 0th layer node being a master node and other layer nodes being slave nodes, the slave nodes being connected with upper layer nodes through power line carrier communication links and / or wireless communication links, the master node and the slave nodes being provided with zero-crossing detection circuits, the time calibration device being arranged in a slave node in the power distribution network, the time calibration device comprising: An upper layer node time calibration beacon receiving module configured to receive a time calibration beacon sent by an upper layer node of the slave node after the upper layer node completes time calibration, the time calibration beacon containing time calibration information, the time calibration information including a time value of a sending time of the time calibration beacon and an NTB time difference between the sending time and a first zero-crossing time of a phase line where the upper layer node is located, the time value of the sending time of the time calibration beacon being counted by a local clock of the upper layer node sending the time calibration beacon; An NTB time difference obtaining module configured to obtain an NTB time difference between a receiving time of the time calibration beacon and a second zero-crossing time of a phase line where the slave node is located; A slave node time calibration module configured to calibrate the slave node according to the time calibration information in the received time calibration beacon and the NTB time difference between the receiving time of the time calibration beacon and the second zero-crossing time of the phase line where the slave node is located; The upper layer node of the slave node includes the master node, the master node being a designated node in the power distribution network or a node calibrated through the designated node, the designated node including a multi-source fusion node or a node other than the multi-source fusion node, the multi-source fusion node supporting multi-source time service fusion, and the designated node in the power distribution network being calibrated through the multi-source fusion node in the following manner: Obtaining multiple time services respectively from multiple different time service sources; Determining one or more first intermediate value sets according to the multiple time services, the first intermediate value set being determined according to time services from at least two different time service sources; In the case where the first intermediate value set is multiple, the elements in the first intermediate value set are multiple, a corresponding multiple second intermediate values are determined according to the multiple first intermediate value sets, respectively; for each first intermediate value set, the second intermediate value is determined according to a credibility of a time service source corresponding to the first intermediate value set or according to a time service deviation value between time services of the time service source corresponding to the first intermediate value set; a target second intermediate value is selected from the multiple second intermediate values according to a preset rule; and the designated node is calibrated according to the first intermediate value set corresponding to the target second intermediate value; In the case where the first intermediate value set is one, the element in the first intermediate value set is one or more, and the designated node is calibrated according to the first intermediate value set.

52. The timekeeping apparatus of claim 51, wherein, The slave node is also connected with a lower layer node through a power line carrier communication link and / or a wireless communication link, and the time calibration device further comprises: The slave node time calibration beacon sending module is configured to send a time calibration beacon to the lower layer node after the slave node completes time calibration, so that the lower layer node calibrates local time according to time calibration information in the received time calibration beacon.

53. A timekeeping device for a power distribution network, wherein, The power utilization network adopts a hierarchical networking manner and includes multiple layer nodes, the 0th layer node is a master node, and other layer nodes except the 0th layer node are slave nodes, the master node is connected with lower layer slave nodes through a power line carrier communication link and / or a wireless communication link, the master node and the slave node are both provided with a zero-crossing detection circuit, the time calibration device is arranged in the master node in the power utilization network, and the time calibration device includes: The master node time calibration beacon sending module is configured to send a time calibration beacon to the lower layer slave node after completing time calibration, so as to realize time calibration of the lower layer slave node; the time calibration beacon contains time calibration information, so that the lower layer slave node calibrates local time according to a NTB time difference between time calibration information in the time calibration beacon and a time difference between a time when the time calibration beacon is received and a zero-crossing time of a phase line where the lower layer slave node is located; wherein the time calibration information includes a time value of a time when the time calibration beacon is sent and a NTB time difference between the time when the time calibration beacon is sent and a zero-crossing time of a phase line where the master node is located, and the time value of the time when the time calibration beacon is sent is counted by a local clock of the master node; The master node is a designated node in the power utilization network or a node that is calibrated through the designated node, the designated node includes a multi-source fusion node or a node other than the multi-source fusion node, the multi-source fusion node supports multi-source time service fusion, and the designated node in the power utilization network is calibrated through the multi-source fusion node in the following manner: Obtain multiple time services respectively from multiple different time service sources; Determine one or more first intermediate value sets according to the multiple time services, the first intermediate value set is determined according to time services from at least two different time service sources; In the case that the first intermediate value set is multiple, the elements in the first intermediate value set are multiple, a corresponding multiple second intermediate values are determined according to the multiple first intermediate value sets; for each first intermediate value set, the second intermediate value is determined according to a credibility of a time service source corresponding to the first intermediate value set or according to a time service time deviation value between time services of the time service source corresponding to the first intermediate value set; a target second intermediate value is selected from the multiple second intermediate values according to a preset rule; and the designated node is calibrated according to a first intermediate value set corresponding to the target second intermediate value; In the case that the first intermediate value set is one, the element in the first intermediate value set is one or more, and the designated node is calibrated according to the first intermediate value set.

54. A multi-source wide-area electric utility network hierarchical time synchronization system, wherein, The time correction system comprises a plurality of nodes, at least one of which is a multi-source fusion node supporting time correction of a plurality of different time sources; the time correction system further comprises an end wireless device connected to the nodes in the time correction system; wherein: The multi-source fusion node is configured to correct the time of a specified node in the time correction system in the following manner: the specified node includes the multi-source fusion node or a node other than the multi-source fusion node: Obtain a plurality of time correction times respectively from a plurality of different time sources; Determine one or more first intermediate value sets according to the plurality of time correction times, the first intermediate value set being determined according to time correction times from at least two different time sources; In the case of a plurality of first intermediate value sets, the elements in the first intermediate value set are a plurality, and a plurality of second intermediate values are determined according to the plurality of first intermediate value sets respectively; wherein, for each first intermediate value set, the second intermediate value is determined according to the credibility of the time source corresponding to the first intermediate value set, or according to the time correction time deviation value between the time correction times of the time source corresponding to the first intermediate value set; a target second intermediate value is selected from the plurality of second intermediate values according to a predetermined rule; and the specified node is corrected according to the first intermediate value set corresponding to the target second intermediate value; In the case of one first intermediate value set, the element in the first intermediate value set is one or more, and the specified node is corrected according to the first intermediate value set; The specified node is configured to correct the time of other nodes in the time correction system after completing the time correction; Wherein, after completing the time correction, the nodes in the time correction system connected to the end wireless device obtain a time correction period of the end wireless device according to the time error coefficient of the end wireless device connected to the node and the maximum time synchronization tolerance threshold; and correct the time of the end wireless device according to the time correction period.

55. A chip, wherein, The time correction device of any one of claims 45-53; or, comprising a memory and a processor; wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the time correction method of any one of claims 1-44.

56. An electronic device, comprising: Comprising a memory and a processor; wherein the memory is used to store computer instructions, wherein the computer instructions are executed by the processor to implement the time correction method of any one of claims 1-44.

57. A computer readable storage medium having stored thereon computer instructions, wherein, The computer instructions are executed by the processor to implement the time correction method of any one of claims 1-44.

58. A computer program product comprising computer instructions, wherein, The computer instructions are executed by the processor to implement the time correction method of any one of claims 1-44. The computer instructions are executed by the processor to implement the time correction method of any one of claims 1-44.

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