Power distribution and utilization network timing method, device, system and chip based on zero-crossing reference

Abstract

The invention relates to the technical field of power distribution and utilization and communication, in particular to a power distribution and utilization network time calibration method, device, system and chip based on zero-crossing benchmark, and the time calibration method comprises the following steps: after an upper-layer node of a slave node finishes time calibration, the slave node receives a time calibration beacon containing time calibration information sent by the upper-layer node, then, the NTB time difference between the receiving moment of the time calibration beacon and the second zero-crossing moment of the phase line where the slave node is located is obtained; and finally, according to the received time calibration information in the 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, performing time calibration. According to the invention, a layered timing mode is adopted, that is, the slave node carries out time calibration directly according to the timing information of the direct upper layer node, so that the communication time delay and error accumulation caused by multi-stage forwarding of the timing information are effectively reduced, the timing precision is improved, and the reliability of the power distribution and utilization network is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of power distribution and communication technology, and in particular to a method, device, system and chip for synchronizing a power distribution network based on a zero-crossing reference. Background Art

[0002] The power system is the most critical infrastructure and is vital to the national economy and security. The power system is geographically dispersed. To achieve continuous monitoring of the grid operation status, rapid identification and location of faults, timely response and repair, etc., it is necessary to easily obtain standard time on a large scale to maintain the time synchronization of the power system.

[0003] With the continuous advancement of smart grid construction and the continuous development of technology, the requirements for time synchronization are becoming higher and higher. In the power distribution network, the high degree of time calibration and synchronization of each node terminal is the core foundation for realizing functions such as efficient data collection, intelligent control, fault warning and remote management. Each node in the power distribution network not only needs to accurately record power consumption information, but also needs to work together based on a unified time reference to ensure the accuracy and real-time nature of data analysis.

[0004] In terms of time calibration and synchronization from power distribution terminals to meter equipment nodes, since power lines are the most popular and widely covered physical media, using power lines to transmit data information is extremely convenient. Without rewiring, all electrical appliances connected to power lines can 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.

[0005] At present, the published high-speed power line carrier and high-speed dual-mode communication protocols stipulate that all nodes in the power distribution network support the terminal to calibrate the time of the electric energy meter. When calibrating the time, a certain device (such as the central coordination node CCO) can be selected as the master node, and its clock can be set as the reference time, and other devices (such as the proxy coordination node PCO and the site STA) can be used as slave nodes. The master node broadcasts the time calibration information (such as timestamp, time signal, etc.) to the slave node regularly or according to demand. The slave node receives the time calibration information and adjusts its own clock according to the received information to achieve time synchronization with the master node.

[0006] Although power line carrier technology is popular due to its high penetration 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 power load changes, line aging, harmonic interference, etc. These factors will cause signal attenuation and distortion, thereby affecting communication quality and the reliability of time synchronization. Secondly, due to the large range of the power distribution network, the signal needs to be forwarded in layers through multiple relay nodes during transmission, which not only increases the communication delay, but also may cause the error accumulation in each level of forwarding, resulting in a significant increase in the terminal node timing deviation and reduced timing accuracy.

[0007] How to improve the timing accuracy of each node in the power distribution network during clock synchronization, thereby improving the reliability and stability of the power distribution network, is an urgent problem to be solved. Summary of the invention

[0008] In order to solve the problems in the related art, the embodiments of the present disclosure provide a method, device, system and chip for timing a distribution and utilization power network based on a zero-crossing reference.

[0009] In a first aspect, a time synchronization method for a power distribution network based on a zero-crossing reference is provided in an embodiment of the present disclosure. The time synchronization method is applied to a slave node in the power distribution network. The power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, wherein the multiple layers of nodes include a master node and a slave node, wherein the 0th layer node is a master node, and the nodes of other layers except the 0th layer node are slave nodes, and the master node and the slave node are both provided with a zero-crossing detection circuit. The time synchronization method includes:

[0010] After the upper node of the slave node completes the time calibration, a time calibration beacon sent by the upper node is received, wherein the time calibration beacon contains the time calibration information, and the time calibration information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the first zero-crossing time of the phase line where the upper node sending the time calibration beacon is located, wherein the time value of the sending time of the time calibration beacon is timed by the local clock of the upper node sending the time calibration beacon;

[0011] Obtaining 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;

[0012] The slave node is timed according to the time calibration 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.

[0013] According to an embodiment of the present disclosure:

[0014] The first zero-crossing time and the second zero-crossing time are the same zero-crossing time; or

[0015] There is a preset relationship between the first zero-crossing time and the second zero-crossing time.

[0016] According to an embodiment of the present disclosure, the time synchronization method further includes:

[0017] After the slave node completes the time calibration, it sends a time calibration beacon to the lower-level node, so that the lower-level node performs time calibration according to the time calibration information in the received time calibration beacon.

[0018] According to an embodiment of the present disclosure, 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 reception time of the time calibration beacon and the second zero crossing time of the phase line where the slave node is located includes:

[0019] Obtaining a time calibration NTB time difference according to the NTB time difference in the time calibration information, wherein the time calibration NTB time difference corresponds to the phase line where the slave node is located;

[0020] Calculate the time calibration beacon transmission delay time according to 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;

[0021] Calculate the calibration time corresponding to the reception time of the time calibration beacon according to the transmission delay time of the time calibration beacon and the time value of the sending time in the calibration information;

[0022] The time is calibrated using the calibration time corresponding to the reception time of the time calibration beacon.

[0023] According to an embodiment of the present disclosure, 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; 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 includes:

[0024] When the NTB time difference in the timing information includes the first NTB time difference, the second NTB time difference and the third NTB time difference, the NTB time difference in the timing information corresponding to the phase line where the slave node is located is used as the timing NTB time difference;

[0025] When the NTB time difference in the timing 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 that sends the time calibration beacon and the slave node are in-phase nodes, the NTB time difference in the timing information is used as the timing NTB time difference;

[0026] When the NTB time difference in the timing 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 that sends the time calibration beacon and the slave node are not in phase, obtain two NTB time differences corresponding to the phase line where the slave node is located and the phase line where the upper node that sends the time calibration beacon is located, obtain the difference between the two NTB time differences, and subtract the difference from the NTB time difference in the timing information to obtain the timing NTB time difference.

[0027] According to an embodiment of the present disclosure, the time calibration beacon transmission delay time is calculated using the following formula:

[0028] T Intv =ΔT NTB-L +n TABC -ΔT NTB ;

[0029] The calibration time corresponding to the reception time of the time calibration beacon is calculated using the following formula:

[0030] T P =T Intv +T c ;

[0031] Among them, T P represents the calibration time corresponding to the reception time of the time calibration beacon; T Intv represents the transmission delay time of the time calibration beacon; T c Indicates the time value of the sending time in the timing information; ΔT NTB-L 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; T ABC is the power frequency cycle; n is the number of power frequency cycles spanned by the time calibration beacon transmission, n≥0, ΔT NTB It is the time difference of the time calibration NTB.

[0032] According to an embodiment of the present disclosure, the power distribution network further includes a terminal wireless node, the terminal wireless node is connected to its parent node via a wireless communication link, and the parent node includes: a master node or a slave node in the power distribution network; the time synchronization method further includes:

[0033] When the parent node completes the time calibration, the time calibration period of the terminal wireless node is obtained according to the time error coefficient of the terminal wireless node connected to the parent node and the maximum time synchronization tolerance threshold;

[0034] The terminal wireless node is time-synchronized according to the time-synchronization period.

[0035] According to an embodiment of the present disclosure, the step of acquiring the timing period of the terminal wireless node according to the time error coefficient of the terminal wireless node connected to the parent node and the maximum time synchronization tolerance threshold comprises:

[0036] Obtain the time error coefficient of the terminal wireless node to form a time error coefficient set Q α , recorded as: Q α ={α1, α2, ... α n}; where n represents the number of the terminal wireless nodes, and the time error coefficient α of the i-th terminal wireless node i is the time interval T between two time calibrations performed by the parent node of the i-th terminal wireless node on the i-th terminal wireless node b , and the internal clock time error Δt of the i-th terminal wireless node after the two calibrations i , calculated by the following formula:

[0037] α i =Δt i / T b , where Δt i =|T i2 -T i1 |, T i1 The internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the first time calibration on the i-th terminal wireless node, T i2 The internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the second time calibration on the i-th terminal wireless node;

[0038] Obtain the maximum time synchronization tolerance threshold of the terminal wireless node; calculate the maximum timing cycle of the terminal wireless node according to the maximum time synchronization tolerance threshold and the time error coefficient set to form a maximum timing cycle set {T MAX_1 , T MAX_2 ,…T MAX_n}, where the maximum timing period T of the i-th terminal wireless node MAX_i =Δt MAX_i / α i , Δt MAX_i is the maximum time synchronization tolerance threshold of the i-th terminal wireless node;

[0039] Time slot allocation is performed according to the maximum timing cycle of the terminal wireless node to obtain the timing cycle of the terminal wireless node.

[0040] According to an embodiment of the present disclosure, the time synchronization method further includes:

[0041] Determine the optimization goal:

[0042]

[0043] Among them, p c The power consumption generated by the parent node in calibrating the terminal wireless node; Δt c is the channel time occupied by the parent node to calibrate the terminal wireless node, β T is the threshold of the channel occupation ratio of the parent node to the terminal wireless node for timing calibration, T i is the time calibration period of the i-th terminal wireless node;

[0044] According to the optimization target, the timing period {T1, T2, ...T n};

[0045] The step of calibrating the terminal wireless node according to the calibration period includes:

[0046] The terminal wireless node is time-synchronized according to the optimized time-synchronization period.

[0047] In a second aspect, a time synchronization method for a power distribution network based on a zero-crossing reference is provided in an embodiment of the present disclosure. The time synchronization method is applied to a master node in a power distribution network. The power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, wherein the multiple layers of nodes include a master node and a slave node, wherein the 0th layer node is a master node, and other layer nodes except the 0th layer node are slave nodes, and the master node and the slave node are both provided with a zero-crossing detection circuit, and the time synchronization method includes:

[0048] Perform time calibration according to the preset time calibration method;

[0049] A time calibration beacon is sent to the lower-level slave node to realize time calibration of the lower-level slave node; the time calibration beacon contains time calibration information, so that the lower-level slave node can perform time calibration according to the time calibration 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 calibration information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the zero-crossing time of the phase line where the master node is located, and the time value of the sending time of the time calibration beacon is timed by the local clock of the master node.

[0050] According to an embodiment of the present disclosure,

[0051] 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, and the first NTB time difference, the second NTB time difference and the third NTB time difference correspond to three different phase lines respectively.

[0052] In a third aspect, an embodiment of the present disclosure provides a time-keeping device for a power distribution network based on a zero-crossing reference, wherein the time-keeping device is arranged at a slave node in the power distribution network, wherein the power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, wherein the multiple layers of nodes include a master node and a slave node, wherein the 0th layer node is a master node, and the nodes of other layers except the 0th layer node are slave nodes, and the master node and the slave node are both provided with a zero-crossing detection circuit, and the time-keeping device includes:

[0053] The upper node time calibration beacon receiving module is configured to receive the time calibration beacon sent by the upper node after the upper node of the slave node completes the time calibration, wherein the time calibration beacon contains the time calibration information, and the time calibration information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the first zero-crossing time of the phase line where the upper node sending the time calibration beacon is located, wherein the time value of the sending time of the time calibration beacon is timed by the local clock of the upper node sending the time calibration beacon;

[0054] An NTB time difference acquisition module is configured to acquire an NTB time difference between a reception time of the time calibration beacon and a second zero-crossing time of the phase line where the slave node is located;

[0055] The slave node timing module is configured to perform timing on the slave node according to the timing 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.

[0056] According to an embodiment of the present disclosure, the first zero-crossing moment and the second zero-crossing moment are the same zero-crossing moment; or there is a preset relationship between the first zero-crossing moment and the second zero-crossing moment.

[0057] According to an embodiment of the present disclosure, the time calibration device further includes:

[0058] The slave node time calibration beacon sending module is configured to send a time calibration beacon to a lower-level node after the slave node completes time calibration, so that the lower-level node performs time calibration according to the time calibration information in the received time calibration beacon.

[0059] According to an embodiment of the present disclosure, 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 reception time of the time calibration beacon and the second zero crossing time of the phase line where the slave node is located includes:

[0060] Obtaining a time calibration NTB time difference according to the NTB time difference in the time calibration information, wherein the time calibration NTB time difference corresponds to the phase line where the slave node is located;

[0061] Calculate the time calibration beacon transmission delay time according to 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;

[0062] Calculate the calibration time corresponding to the reception time of the time calibration beacon according to the transmission delay time of the time calibration beacon and the time value of the sending time in the calibration information;

[0063] The time is calibrated using the calibration time corresponding to the reception time of the time calibration beacon.

[0064] According to an embodiment of the present disclosure, 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; 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 includes:

[0065] When the NTB time difference in the timing information includes the first NTB time difference, the second NTB time difference and the third NTB time difference, the NTB time difference in the timing information corresponding to the phase line where the slave node is located is used as the timing NTB time difference;

[0066] When the NTB time difference in the timing 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 that sends the time calibration beacon and the slave node are in-phase nodes, the NTB time difference in the timing information is used as the timing NTB time difference;

[0067] When the NTB time difference in the timing 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 that sends the time calibration beacon and the slave node are not in phase, obtain two NTB time differences in the time calibration beacon sent by the master node that correspond to the phase line where the slave node is located and the phase line where the upper node that sends the time calibration beacon is located, obtain the difference between the two NTB time differences, and subtract the difference from the NTB time difference in the timing information to obtain the timing NTB time difference.

[0068] According to an embodiment of the present disclosure, the time calibration beacon transmission delay time is calculated using the following formula:

[0069] T Intv =ΔT NTB-L +nT ABC -ΔT NTB ;

[0070] The calibration time corresponding to the reception time of the time calibration beacon is calculated using the following formula:

[0071] T P =T Intv +T c ;

[0072] Among them, T P represents the calibration time corresponding to the reception time of the time calibration beacon; T Intv represents the transmission delay time of the time calibration beacon; T c Indicates the time value of the sending time in the timing information; ΔT NTB-L 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; T ABC is the power frequency cycle; n is the number of power frequency cycles spanned by the time calibration beacon transmission, n≥0, ΔT NTB It is the time difference of the time calibration NTB.

[0073] According to an embodiment of the present disclosure, the power distribution network further includes a terminal wireless node, the terminal wireless node is connected to its parent node via a wireless communication link, and the parent node includes: a master node or a slave node in the power distribution network; the timing device further includes a terminal wireless node timing module, wherein the terminal wireless node timing module includes:

[0074] A timing cycle acquisition unit is configured to acquire the timing cycle of the terminal wireless node according to the time error coefficient of the terminal wireless node connected to the parent node and the maximum time synchronization tolerance threshold after the parent node completes the timing.

[0075] The terminal wireless node timing unit is configured to perform timing calibration on the terminal wireless node according to the timing calibration period.

[0076] According to an embodiment of the present disclosure, the timing cycle acquisition unit includes:

[0077] The time error coefficient acquisition unit is configured to acquire the time error coefficient of the terminal wireless node to form a time error coefficient set Q α , recorded as: Q α ={α1, α2, ... α n}; where n represents the number of the terminal wireless nodes, and the time error coefficient α of the i-th terminal wireless node i is the time interval T between two time calibrations performed by the parent node of the i-th terminal wireless node on the i-th terminal wireless node b , and the internal clock time error Δt of the i-th terminal wireless node after the two calibrations i , calculated by the following formula:

[0078] α i =Δt i / T b , where Δt i =|T i2 -T i1 |, T i1 The internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the first time calibration on the i-th terminal wireless node, T i2 The internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the second time calibration on the i-th terminal wireless node;

[0079] A maximum time synchronization tolerance threshold acquisition unit, configured to acquire a maximum time synchronization tolerance threshold of the terminal wireless node;

[0080] The maximum timing cycle calculation unit is configured to calculate the maximum timing cycle of the terminal wireless node according to the maximum time synchronization tolerance threshold and the time error coefficient set to form a maximum timing cycle set {T MAX_1 , T MAX_2 ,…T MAX_n}, where the maximum timing period T of the i-th terminal wireless node MAX_i =Δt MAX_i / α i , Δt MAX_i is the maximum time synchronization tolerance threshold of the i-th terminal wireless node;

[0081] The terminal wireless node timing cycle acquisition unit is configured to perform time slot allocation according to the maximum timing cycle of the terminal wireless node to obtain the timing cycle of the terminal wireless node.

[0082] According to an embodiment of the present disclosure, the timing cycle acquisition unit further includes:

[0083] The optimization target determination unit is configured to determine the optimization target:

[0084]

[0085] Among them, p c The power consumption generated by the parent node in calibrating the terminal wireless node; Δt c is the channel time occupied by the parent node to calibrate the terminal wireless node, β T is the threshold of the channel occupation ratio of the parent node to the terminal wireless node for timing calibration, T i is the time calibration period of the i-th terminal wireless node;

[0086] The timing cycle optimization unit is configured to optimize the timing cycle {T1, T2, ...T n};

[0087] The step of calibrating the terminal wireless node according to the calibration period includes:

[0088] The terminal wireless node is time-synchronized according to the optimized time-synchronization period.

[0089] In a fourth aspect, an embodiment of the present disclosure provides a time-keeping device for a power distribution network based on a zero-crossing reference, wherein the time-keeping device is arranged at a master node in the power distribution network, wherein the power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, wherein the multiple layers of nodes include a master node and a slave node, wherein the 0th layer node is a master node, and the nodes of other layers except the 0th layer node are slave nodes, and the master node and the slave node are both provided with a zero-crossing detection circuit, and the time-keeping device includes:

[0090] The master node timing module is configured to perform timing according to a preset timing method;

[0091] The master node time calibration beacon sending module is configured to send time calibration beacons to lower-level slave nodes to implement time calibration of the lower-level slave nodes; the time calibration beacon contains time calibration information so that the lower-level slave nodes can perform time calibration based on the time calibration 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 slave node is located; wherein the time calibration information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the zero-crossing time of the phase line where the master node is located, and the time value of the sending time of the time calibration beacon is based on the local clock of the master node.

[0092] According to an embodiment of the present disclosure,

[0093] 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, and the first NTB time difference, the second NTB time difference and the third NTB time difference correspond to three different phase lines respectively.

[0094] In a fifth aspect, an embodiment of the present disclosure provides a first electronic device, comprising a first memory and a first processor; wherein the first memory is used to store computer instructions, wherein the computer instructions are executed by the first processor to implement the time synchronization method described in any one of the first aspects.

[0095] In a sixth aspect, a second electronic device is provided in an embodiment of the present disclosure, comprising a second memory and a second processor; wherein the second memory is used to store computer instructions, wherein the computer instructions are executed by the second processor to implement the time synchronization method described in any one of the second aspects.

[0096] In a seventh aspect, an embodiment of the present disclosure provides a power distribution network timing system based on a zero-crossing reference, wherein the power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, wherein the multiple layers of nodes include a master node and a slave node, wherein the 0th layer node is a master node, and the nodes of other layers except the 0th layer node are slave nodes, and the timing system includes slave nodes and master nodes in the power distribution network, wherein the master node and the slave node are both provided with a zero-crossing detection circuit, wherein:

[0097] The slave node comprises the time calibration device according to any one of the third aspect of the claim, or is implemented as the first electronic device according to the fifth aspect of the claim; and / or

[0098] The master node includes the time calibration device described in the fourth aspect, or is implemented as the second electronic device described in the sixth aspect.

[0099] In the eighth aspect, a chip is provided in an embodiment of the present disclosure, comprising the time calibration device described in any one of the third aspect and the fourth aspect; 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 calibration method described in any one of the first aspect and the second aspect.

[0100] In a ninth aspect, a computer-readable storage medium is provided in an embodiment of the present disclosure, on which computer instructions are stored. When the computer instructions are executed by a processor, the time calibration method described in any one of the first aspect and the second aspect is implemented.

[0101] In a tenth aspect, a computer program product is provided in an embodiment of the present disclosure, comprising computer instructions, which, when executed by a processor, implement the time calibration method described in any one of the first aspect and the second aspect.

[0102] According to the technical solution provided by the embodiment of the present disclosure, when the upper node of the slave node in the power distribution network completes the time calibration, the slave node receives the time calibration beacon sent by its upper node, and the time calibration beacon contains the time calibration information, and the time calibration information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the first zero-crossing time of the phase line where the upper node that sends the time calibration beacon is located, and then 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 is obtained, and finally the slave node is calibrated 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.

[0103] By adopting a hierarchical timing method based on zero-crossing reference, that is, the slave node directly calibrates the time based on the timing information of its direct upper node, rather than all slave nodes relying on the timing information of the master node. This timing method effectively reduces the communication delay and error accumulation caused by multi-level forwarding of timing information. In addition, the transmission delay of the timing information from the upper node to the slave node is determined based on the zero-crossing reference, making the transmission delay more accurate. In this way, each level of node can be adjusted based on the latest and most accurate timing information, thereby ensuring the high consistency of the time of each node in the power distribution network, significantly improving the timing accuracy, and effectively solving the problem of low timing accuracy and poor reliability of each node in the power distribution network during time synchronization, and improving the reliability and stability of the power distribution network.

[0104] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] Other features, objectives and advantages of the present disclosure will become more apparent through the following detailed description of non-limiting embodiments in conjunction with the accompanying drawings. In the accompanying drawings:

[0106] Figure 1 A flow chart of a method for timing distribution and utilization network based on a zero-crossing reference according to an embodiment of the present disclosure is shown.

[0107] Figure 2 A schematic diagram of a power distribution network structure connection according to an embodiment of the present disclosure is shown.

[0108] Figure 3 A flow chart of a method for calibrating time by a slave node according to an embodiment of the present disclosure based on the timing information in a 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 is shown.

[0109] Figure 4 A schematic diagram is shown of a process of sending a time calibration beacon from an upper node to a slave node according to an embodiment of the present disclosure.

[0110] Figure 5 A flow chart of another method for timing distribution and utilization network based on zero-crossing reference according to an embodiment of the present disclosure is shown.

[0111] Figure 6 A schematic diagram of communication connection between a terminal wireless node and a station node according to an embodiment of the present disclosure is shown.

[0112] Figure 7 A flow chart of another method for synchronizing time in a distribution and utilization power network based on a zero-crossing reference according to an embodiment of the present disclosure is shown.

[0113] Figure 8 A flow chart of another method for synchronizing time in a distribution and utilization power network based on a zero-crossing reference according to an embodiment of the present disclosure is shown.

[0114] Fig. 9 A structural block diagram of a distribution and utilization network timing device based on a zero-crossing reference according to an embodiment of the present disclosure is shown.

[0115] Fig.10 A structural block diagram of another distribution and utilization network timing device based on a zero-crossing reference according to an embodiment of the present disclosure is shown.

[0116] Fig.11 A structural block diagram of a first electronic device according to an embodiment of the present disclosure is shown.

[0117] Fig.12 A structural block diagram of a second electronic device according to an embodiment of the present disclosure is shown.

[0118] Fig.13A structural diagram of a distribution and utilization network timing system based on a zero-crossing reference according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0119] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement them. In addition, for the sake of clarity, parts not related to the description of the exemplary embodiments are omitted in the accompanying drawings.

[0120] In the present disclosure, it should be understood that terms such as "include" or "have" are intended to indicate the presence of features, numbers, steps, behaviors, components, parts, or a combination thereof disclosed in the present specification, and are not intended to exclude the possibility that one or more other features, numbers, steps, behaviors, components, parts, or a combination thereof exist or are added.

[0121] It should also be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0122] As mentioned above, when the power distribution network in the prior art synchronizes the clocks of all nodes in the network, the local time of the master node is used as the reference time. The master node broadcasts the timing information to the slave nodes. The slave nodes receive the timing information and adjust their own clocks according to the received information, thereby achieving time synchronization with the master node.

[0123] In the above-mentioned time synchronization method of the prior art, all slave nodes rely on the time synchronization information of the master node for synchronization. During the transmission of the time synchronization information, due to factors such as network transmission delay and device processing time, the time synchronization information received by the slave node will have time deviation. This deviation is particularly obvious when the network scale is large or the communication conditions are complex, and it cannot meet the needs of high-precision time synchronization.

[0124] In order to improve the time synchronization accuracy of each node in the power distribution network during clock synchronization, thereby improving the reliability and stability of the power distribution network, the inventors of the present invention, after careful research and consideration, abandoned the traditional single synchronization method of the master node broadcasting the time synchronization information of the entire network, and instead adopted a hierarchical time synchronization strategy based on a hierarchical structure and the phase line zero crossing time difference (NTB time difference), making full use of the hierarchical relationship between nodes in the network and the physical property of the phase line voltage crossing zero in the power system, to optimize the clock synchronization mechanism in the power distribution network.

[0125] Specifically, firstly, the hierarchical timing concept is introduced in the present disclosure, that is, the slave node not only receives the timing information of the master node, but also receives the timing information of its directly upper node. In this way, each node can perform timing according to its own directly upper node, reducing communication delay and error accumulation; secondly, the stable and measurable physical phenomenon of phase line voltage zero crossing in the power system is used to combine time calibration with power waveform. While receiving the timing information, each slave node records the NTB time difference between the receiving time and the local phase line voltage zero crossing point, and compares it with the NTB time difference in the timing information and adjusts the local time, thereby realizing accurate calibration of the local time. After each slave node completes its own timing, it will send a time calibration beacon that has been calibrated by itself to the next layer of nodes. In this way, the clock synchronization process in the entire network forms a chain of hierarchical transmission and layer-by-layer calibration. Through the accurate measurement and comparison of hierarchical timing and NTB time difference, the influence of communication delay and error accumulation on timing accuracy is effectively reduced. At the same time, the hierarchical timing method also makes the system have better fault tolerance and scalability.

[0126] Figure 1 A flow chart of a time synchronization method for a power distribution network based on a zero-crossing reference according to an embodiment of the present disclosure is shown, wherein the time synchronization method is applied to a slave node in the power distribution network.

[0127] Figure 2 FIG. 1 shows a schematic diagram of a power distribution network structure connection according to an embodiment of the present disclosure. Figure 2 As shown, the power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes ( Figure 2 The 4-layer node is used as an example for explanation), the multi-layer nodes include master nodes and slave nodes, wherein the 0th layer node is the master node, and the other layer nodes except the 0th layer node are slave nodes.

[0128] Specifically, the master node includes but is not limited to the central coordination node CCO. The CCO can manage multiple devices in the substation area, such as electricity meters, branch switches, etc., and realize data collection and transmission through communication methods such as broadband carriers. Therefore, CCO is usually selected as the master node because of its powerful communication capabilities and key role in the substation network. With the continuous development of technologies such as the Internet of Things and edge computing, the master nodes in the power distribution network may be more diversified in the future. For example, devices with stronger processing capabilities and more integrated functions, such as smart fusion terminals and edge computing devices, may also become master nodes. In the embodiments of the present disclosure, the master node is taken as CCO for illustrative purposes.

[0129] The slave nodes include but are not limited to proxy coordination nodes PCO and / or stations STA. With the continuous development of Internet of Things technology, more new smart devices may be connected to the power distribution network in the future. These devices may have multiple functions such as data collection, processing, and communication, thus becoming new slave nodes. In the embodiments of the present disclosure, the slave nodes are PCO and / or STA for exemplary description.

[0130] Wherein, the slave node is connected to the upper node via a power line carrier communication link and / or a wireless communication link. 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 and / or a narrowband wireless communication link. Figure 2 As shown, CCO is the PCO in the first layer node 1-1 、PCO 1-2 , STA 1-1 , STA 1-2 The upper node, PCO 1-1 PCO for Layer 2 nodes 2-1 , STA 2-1 The upper node, PCO 1-2 PCO for Layer 2 nodes 2-2 , STA 2-2 , STA 2-3 The upper node, PCO 2-1 STA in the layer 3 node 3-1 , STA 3-2 The upper node, PCO 2-2 STA in the layer 3 node 3-3 , STA 3-4 The upper node of .

[0131] The master node and slave node involved in the embodiments of the present disclosure are both provided with a high-precision zero-crossing detection circuit, which detects the zero-crossing moment of the phase line. The power line usually has multiple phases (such as A, B, and C). For the master node, the master node is configured with a high-precision zero-crossing detection circuit that can simultaneously detect the three-phase power lines A, B, and C, and can capture each zero-crossing point of the three-phase voltage in real time, that is, the moment when the voltage crosses the zero point from positive to negative (or from negative to positive) in each power frequency cycle. Whenever the zero-crossing point of any phase is detected, the master node will accurately record the timestamp of the moment and accurately establish a sequence of three-phase zero-crossing NTB moments; unlike the master node, the slave node can only connect one phase line to detect the voltage zero-crossing point of the phase (A, B, or C) to which it is connected, or it can be connected to multiple phase lines to detect the voltage zero-crossing points of multiple phases. When the slave node detects that the voltage of the phase line connected to it crosses zero, it will also record the timestamp of this moment. Usually, the accuracy of the high-precision zero-crossing detection circuit is about 2μs.

[0132] like Figure 1 As shown, the time calibration method includes the following steps S110 to S130:

[0133] In step S110, after the upper node of the slave node completes time calibration, it receives a time calibration beacon sent by the upper node, wherein the time calibration beacon contains time calibration information, and the time calibration information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the first zero-crossing time of the phase line where the upper node that sends the time calibration beacon is located, wherein the time value of the sending time of the time calibration beacon is based on the local clock of the upper node that sends the time calibration beacon.

[0134] When a slave node in the power distribution network performs time calibration, the upper node of the slave node needs to complete the time calibration in advance. Figure 2 PCO shown 2-1 , PCO required 1-1 After completing the time calibration according to the time calibration information in the time calibration beacon sent by the CCO, the PCO 1-1 To PCO 2-1 Send a time calibration beacon, and then PCO 2-1 Then according to the received PCO 1-1 The time synchronization information in the time calibration beacon is used for time synchronization. In this way, when the upper node of the slave node completes the time synchronization, it obtains accurate time information, thereby establishing a reliable time reference for subsequent sending of time synchronization information to the slave node. If the time of the upper node itself is inaccurate, the time synchronization information it sends to the slave node will also contain errors. This error will accumulate as the network expands and time passes, and ultimately lead to a significant reduction in the time synchronization accuracy of the entire network. Therefore, ensuring that the upper node completes the time synchronization before the slave node performs the time synchronization can minimize the accumulation of such errors.

[0135] For the master node, it can obtain a high-precision time reference from a time reference source (which can be GPS, NTP server or other high-precision clock) to ensure the accuracy and reliability of its time reference, so that the slave nodes of the entire network can use its time as a reference to achieve accurate time synchronization of the entire network.

[0136] In the present disclosure, the slave node receives a time calibration beacon containing timing information from its upper node via a power line carrier communication link and / or a wireless communication link.

[0137] Among them, the time value of the sending time contained in the time calibration beacon refers to the specific time point when the upper node sends the message, which is timed by its local clock, and the time value of the sending time is used for subsequent time calculation and calibration of the slave node. The NTB time difference contained in the time calibration beacon refers to the NTB time difference between the sending time of the upper node sending the time calibration beacon and the first zero-crossing moment of the phase line where the upper node is located. The first zero-crossing moment refers to the specified zero-crossing moment among the multiple zero-crossing moments of the phase line where the upper node is located, for example: it can be the zero-crossing moment from negative to positive of the phase line voltage closest to the sending moment, which represents a relatively stable and predictable time point and is used as a reference benchmark when sending the time calibration beacon. Since the upper node (master node or slave node) has the ability to collect the power frequency zero-crossing points of three-phase or single-phase lines and can record the three-phase or single-phase zero-crossing NTB moment sequence, therefore, when the upper node specifically obtains the NTB time difference, it can directly obtain the NTB time difference between the current moment and the first zero-crossing moment through the zero-crossing detection circuit while sending the time calibration beacon.

[0138] According to an embodiment of the present disclosure, the NTB time difference includes: any one or more of the first NTB time difference, the second NTB time difference and the third NTB time difference. For example, when the upper node is the master node, the NTB time difference contained in the timing 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 node is a slave node, and the phase line where the slave node is located is any one of the A, B, and C phases, or the slave node uses any one of the multiple phase lines connected to it for timing, then the NTB time difference contained in the corresponding timing 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 respectively. In a specific embodiment, the first NTB time difference corresponds to the A phase line, the second NTB time difference corresponds to the B phase line, and the third NTB time difference corresponds to the C phase line.

[0139] For example: for the master node, since it can simultaneously detect the zero-crossing moment of the three-phase lines A, B, and C, when the master node, as an upper-level node, sends a time calibration beacon, there are three NTB time differences contained in the timing information, namely: the NTB time difference between the sending moment of the time calibration beacon and the zero-crossing moment of phase A, the NTB time difference between the sending moment of the time calibration beacon and the zero-crossing moment of phase B, and the NTB time difference between the sending moment of the time calibration beacon and the zero-crossing moment of phase C; for the slave node, if the slave node can only detect the zero-crossing moment of one phase line, then when the slave node, as an upper-level node, sends a time calibration beacon, there is only one NTB time difference contained, namely: 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 sending moment of the time calibration beacon and the zero-crossing moment of phase A.

[0140] In step S120, 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.

[0141] Since the slave node has the capability to collect the power frequency zero-crossing points of the phase line where it is located and can record the zero-crossing NTB moment sequence of the phase line where it is located, when the slave node specifically obtains the NTB time difference, it can directly obtain the NTB time difference between the current moment and the second zero-crossing moment through the zero-crossing detection circuit while receiving the time calibration beacon. The second zero-crossing moment refers to a specified zero-crossing moment among multiple zero-crossing moments of the phase line where the slave node is located, for example, it can be the zero-crossing moment of the phase line voltage from negative to positive that is closest to the receiving moment.

[0142] The first zero-crossing moment and the second zero-crossing moment may be the same zero-crossing moment. For example, if the slave node and the upper node agree to obtain the NTB time difference based on the most recent zero-crossing moment, then when the upper node and the slave node are in-phase nodes and the time calibration beacon is transmitted in the same power frequency cycle, the first zero-crossing moment and the second zero-crossing moment are the same zero-crossing moment.

[0143] Alternatively, there is a preset relationship between the first zero-crossing moment and the second zero-crossing moment. For example: when the upper node and the slave node are in-phase nodes, but the time calibration beacon is transmitted to the slave node after crossing a power frequency cycle, when the slave node obtains the NTB time difference between the reception time of the time calibration beacon and the second zero-crossing moment of the phase line where the slave node is located, if the nearest zero-crossing moment of the phase line is used as the second zero-crossing moment, then the second zero-crossing moment is one power frequency cycle longer than the first zero-crossing moment. For another example: when the upper node and the slave node are not in-phase nodes, assuming that the upper node is an A-phase node and the slave node is a B-phase node, if the upper node and the slave node both obtain the NTB time difference based on the nearest zero-crossing moment, and the time calibration beacon is transmitted in the same power frequency cycle, then the first zero-crossing moment is the A-phase zero-crossing moment closest to the sending moment, the second zero-crossing moment is the B-phase zero-crossing moment closest to the receiving moment, and the difference between the first zero-crossing moment and the second zero-crossing moment is the time difference between the A and B phases. This time difference can be calculated in a known manner.

[0144] In step S130, the slave node is timed according to the time calibration 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.

[0145] Figure 3 A flow chart of a method for performing time calibration from a slave node according to an embodiment of the present disclosure according to the time calibration information in a 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 is shown, as shown in FIG. Figure 3 As shown, it can be achieved by following the steps S310 to S340:

[0146] In step S310, a time calibration NTB time difference is obtained according to the NTB time difference in the time calibration information, and the time calibration NTB time difference corresponds to the phase line where the slave node is located.

[0147] The principle of time calibration for the slave node in the embodiment of the present disclosure is to use the time value of the sending moment of the time calibration beacon sent by the upper node as the reference time, and obtain the transmission delay between the sending and receiving of the time calibration beacon based on the same zero-crossing moment or two zero-crossing moments with a preset relationship, and then the slave node adjusts the local time to be synchronized with its upper node according to the transmission delay and the reference time.

[0148] Based on the fact that the slave node and the upper node may be located on different phase lines and the upper node may be a master node and a slave node, when obtaining the time calibration NTB time difference used to calculate the time calibration beacon transmission delay time involved in the following step S320, it is divided into the following three scenarios:

[0149] The first scenario: when the NTB time difference in the timing information includes the first NTB time difference, the second NTB time difference and the third NTB time difference, the NTB time difference in the timing information corresponding to the phase line where the slave node is located is used as the timing NTB time difference.

[0150] Figure 4 A schematic diagram of a process from sending a time calibration beacon from an upper node to receiving the time calibration beacon from a slave node according to an embodiment of the present disclosure is shown.

[0151] like Figure 4 As shown, when the master node CCO, as the upper node, calibrates the slave node, the calibration information in the sent time calibration beacon includes three NTB time differences, namely: the NTB time difference ΔT between the sending time of the time calibration beacon and the most recent A phase zero crossing time NTB-A , the NTB time difference ΔT between the sending time of the time calibration beacon and the most recent B phase zero crossing time NTB-B , and the NTB time difference ΔT between the sending time of the time calibration beacon and the most recent C phase zero crossing time NTB-C .

[0152] When the slave node is Figure 4 When the A phase STA1 is shown, the slave node does not select all three NTB time differences sent by the master node when calibrating the time, but selects the NTB time difference corresponding to its own phase line as the calibration NTB time difference for calculating the transmission delay time of the time calibration beacon, that is: ΔT NTB-A .

[0153] Accordingly, when the slave node is Figure 4 When the B phase STA2 is shown, the slave node selects ΔT NTB-B As the time difference of the calibration beacon transmission delay time; when the slave node is Figure 4 When the C phase STA3 is shown, the slave node selects ΔT NTB-C The NTB time difference is used as the time calibration beacon transmission delay time calculation.

[0154] The second scenario: when the NTB time difference in the timing 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 that sends the time calibration beacon and the slave node are in-phase nodes, the NTB time difference in the timing information is used as the timing NTB time difference.

[0155] like Figure 4 As shown, when A-phase STA1, as the upper node, calibrates the time of slave node A-phase STA5, since the phase lines of both are in phase A, A-phase STA5 can directly use the NTB time difference in the timing information sent by A-phase STA1 as the timing NTB time difference for calculating the time calibration beacon transmission delay time.

[0156] The third scenario: when the NTB time difference in the timing 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 that sends the time calibration beacon and the slave node are not in phase, obtain two NTB time differences in the time calibration beacon sent by the master node that correspond to the phase line where the slave node is located and the phase line where the upper node that sends the time calibration beacon is located, obtain the difference between the two NTB time differences, and subtract the difference from the NTB time difference in the timing information to obtain the timing NTB time difference.

[0157] In the present disclosure, the slave nodes in the power distribution network can all receive the time calibration beacon sent by the master node and obtain the time calibration information therein. However, when performing time calibration, in the first and second scenarios mentioned above, the slave node only uses the time calibration information sent by the upper node for time calibration. In the third scenario, since the upper node and the slave node are located on different phase lines, when calculating the transmission delay time of the time calibration beacon, it is necessary to accurately obtain the zero-crossing moment based on the same phase line. Therefore, when performing time calibration, the slave node not only needs the time calibration information sent by the upper node, but also needs to be combined with the time calibration information sent by the master node.

[0158] According to an embodiment of the present disclosure, it is assumed that: the first NTB time difference corresponds to the A-phase line, the second NTB time difference corresponds to the B-phase line, and the third NTB time difference corresponds to the C-phase line.

[0159] Then: the step of obtaining two NTB time differences in the time calibration beacon sent by the master node, which correspond to the phase line where the slave node is located and the phase line where the upper node that sends the time calibration beacon is located, and obtaining the difference between the two NTB time differences, includes:

[0160] If the phase line where the slave node is located is phase B, the NTB time difference corresponding to the phase line where the slave node is located in the time calibration beacon sent by the master node is the second NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-B , if the phase line where the upper node sending the time calibration beacon is located is phase A, then the NTB time difference corresponding to the phase line where the upper node sending the time calibration beacon is located in the time calibration beacon sent by the master node is the first NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-A ,but:

[0161] The time difference between the two NTB time differences is obtained by the following formula:

[0162] ΔT B-A =ΔT′ NTB-B -ΔT′ NTB-A ;

[0163] If the phase line where the slave node is located is phase A, the NTB time difference corresponding to the phase line where the slave node is located in the time calibration beacon sent by the master node is the first NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-A , if the phase line where the upper node sending the time calibration beacon is located is phase B, then the NTB time difference corresponding to the phase line where the upper node sending the time calibration beacon is located in the time calibration beacon sent by the master node is the second NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-B ,but:

[0164] The time difference between the two NTB time differences is obtained by the following formula:

[0165] ΔT A-B =ΔT′ NTB-A -ΔT′ NTB-B ;

[0166] If the phase line where the slave node is located is phase A, the NTB time difference corresponding to the phase line where the slave node is located in the time calibration beacon sent by the master node is the first NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-A , if the phase line where the upper node sending the time calibration beacon is located is phase C, then the NTB time difference corresponding to the phase line where the upper node sending the time calibration beacon is located in the time calibration beacon sent by the master node is the third NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-C ,but:

[0167] The time difference between the two NTB time differences is obtained by the following formula:

[0168] ΔT A-C =ΔT′ NTB-A -ΔT′ NTB-C ;

[0169] If the phase line where the slave node is located is phase C, the NTB time difference corresponding to the phase line where the slave node is located in the time calibration beacon sent by the master node is the first NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-C , if the phase line where the upper node sending the time calibration beacon is located is phase A, then the NTB time difference in the time calibration beacon sent by the master node and the phase line where the upper node sending the time calibration beacon is located is the third NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-A ,but:

[0170] The time difference between the two NTB time differences is obtained by the following formula:

[0171] ΔT C-A =ΔT′ NTB-C -ΔT′ NTB-A ;

[0172] If the phase line where the slave node is located is phase C, the NTB time difference corresponding to the phase line where the slave node is located in the time calibration beacon sent by the master node is the third NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-C , if the phase line where the upper node sending the time calibration beacon is located is phase B, then the NTB time difference corresponding to the phase line where the upper node sending the time calibration beacon is located in the time calibration beacon sent by the master node is the second NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-B ,but:

[0173] The time difference between the two NTB time differences is obtained by the following formula:

[0174] ΔT C-B =ΔT′ NTB-C -ΔT′ NTB-B ;

[0175] If the phase line where the slave node is located is phase B, the NTB time difference corresponding to the phase line where the slave node is located in the time calibration beacon sent by the master node is the second NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-C, if the phase line where the upper node sending the time calibration beacon is located is phase C, then the NTB time difference corresponding to the phase line where the upper node sending the time calibration beacon is located in the time calibration beacon sent by the master node is the third NTB time difference ΔT′ in the time calibration beacon sent by the master node NTB-B ,but:

[0176] The time difference between the two NTB time differences is obtained by the following formula:

[0177] ΔT B-C =ΔT′ NTB-B -ΔT′ NTB-C ;

[0178] The step of subtracting the difference from the NTB time difference in the time calibration information to obtain the time calibration NTB time difference includes:

[0179] When the NTB time difference in the timing 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 calibration NTB NTB Calculate using the following formula:

[0180] ΔT NTB =ΔT NTB-A -ΔT B-A ;

[0181] When the NTB time difference in the timing 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 calibration NTB NTB Calculate using the following formula:

[0182] ΔT NTB =ΔT NTB-A -ΔT C-A ;

[0183] When the NTB time difference in the timing 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 calibration NTB NTB Calculate using the following formula:

[0184] ΔT NTB =ΔT NTB-B -ΔT C-B ;

[0185] When the NTB time difference in the timing 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 calibration NTB NTBCalculate using the following formula:

[0186] ΔT NTB =ΔT NTB-B -ΔT A-B ;

[0187] When the NTB time difference in the timing 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 calibration NTB NTB Calculate using the following formula:

[0188] ΔT NTB =ΔT NTB-C -ΔT A-C ;

[0189] When the NTB time difference in the timing information is the third NTB time difference ΔT NTB-C , and when the phase line where the slave node is located is phase B, the time difference ΔT of the time calibration NTB NTB Calculate using the following formula:

[0190] ΔT NTB =ΔT NTB-C -ΔT B-C .

[0191] like Figure 4 As shown, when the A-phase STA5 is used as an upper node to calibrate the time of the slave node B-phase STA6, in this case, the B-phase STA6 needs to 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 NTB-A , then obtain the time difference ΔT between the two NTB time differences B-A =ΔT′ NTB-B -ΔT′ NTB-A , and then use the NTB time difference ΔT in the timing information sent by A-phase STA5 NTB-A , calculate the time difference ΔT of NTB NTB =ΔT NTB-A -ΔT B-A .exist Figure 4 The calculated time difference ΔT of the time calibration NTB is NTB A negative value.

[0192] In step S320, the time calibration beacon transmission delay time is calculated according to 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.

[0193] In step S330, the calibration time corresponding to the reception time of the time calibration beacon is calculated according to the transmission delay time of the time calibration beacon and the time value of the sending time in the timing information.

[0194] According to an embodiment of the present disclosure, the time calibration beacon transmission delay time is calculated using the following formula:

[0195] T Intv =ΔT NTB-L +nT ABC -ΔT NTB ;

[0196] The calibration time corresponding to the reception time of the time calibration beacon is calculated using the following formula:

[0197] T P =T Intv +T c ;

[0198] Among them, T P represents the calibration time corresponding to the reception time of the time calibration beacon; T Intv represents the transmission delay time of the time calibration beacon; T c Indicates the time value of the sending time in the timing information; ΔT NTB-L 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; T ABC is the power frequency cycle; n is the number of power frequency cycles spanned by the time calibration beacon transmission, n≥0, ΔT NTB It is the time difference of the time calibration NTB.

[0199] For example: Figure 4 As shown, when the master node CCO, as the upper node, calibrates the time of the A-phase STA1, the master node CCO and STA1 are both set to use the zero-crossing time of the phase line closest to the sending time or the receiving time as the reference. Since the time calibration beacon is transmitted within a power frequency cycle, n=0, the first zero-crossing time and the second zero-crossing time are the same zero-crossing time, then from the master node CCO sending the time calibration beacon to the A-phase STA1 receiving it, the time calibration beacon transmission delay time T Intv for:

[0200] T Intv =ΔT NTB-L -ΔT NTB-A

[0201] Another example: Figure 4As shown, when the master node CCO, as the upper node, calibrates the time of the B-phase STA2, the master node CCO and STA1 are also set to use the zero-crossing time of the phase line closest to the sending time or the receiving time as the reference. Since the B-phase STA2 has crossed a power frequency cycle relative to the sending time when receiving the time calibration beacon, n=1, and the first zero-crossing time and the second zero-crossing time are also different by a power frequency cycle. Then, from the time the master node CCO sends the time calibration beacon to the B-phase STA2 receiving it, the transmission delay time of the time calibration beacon is T Intv for:

[0202] T Intv =ΔT NTB-L +T ABC -ΔT NTB-B

[0203] The A-phase STA1 and the B-phase STA2 use the following formulas to calculate the calibration time corresponding to the reception time of the time calibration beacon:

[0204] T P =T Intv +T c

[0205] For the slave node, it can be determined whether the time calibration beacon is received in the same power frequency cycle or is received across one or more power frequency cycles in the following manner:

[0206] When the slave node receives the time calibration beacon sent by the upper node, it obtains the time value of the reception time of the time calibration beacon measured by the local clock of the slave node, and then 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 node of the slave node. Then, the time difference is compared with a preset error threshold (for example, half of an industrial frequency cycle). If the time difference is less than the preset error threshold, it can be considered that the time calibration beacon is sent and received within the same industrial frequency cycle. Otherwise, it is considered that the time calibration beacon is not sent and received within the same industrial frequency cycle. As for how many industrial frequency cycles are spanned, it can be determined by judging the relationship between the time difference and the preset error threshold. For example, if the time difference contains a preset error threshold, it can be considered that the time calibration beacon is received across an industrial frequency cycle.

[0207] The above judgment method is only one of the specific implementation methods. During the specific implementation, other applicable methods can be selected according to the specific situation of the application equipment.

[0208] In step S340, time calibration is performed using the calibration time corresponding to the reception time of the time calibration beacon.

[0209] The T calculated in step S330 P The time is timed by the local clock of the upper node of the slave node. The slave node calibrates the local time of the reception moment of the time calibration beacon to T P , that is, the time synchronization with the upper-level node is completed.

[0210] Figure 5 A flow chart of another method for timing distribution and utilization network based on zero-crossing reference according to an embodiment of the present disclosure is shown. In addition to steps S110 to S130 described above, the timing method further includes the following step S140:

[0211] In step S140, after the slave node completes the time calibration, it sends a time calibration beacon to the lower-level node, so that the lower-level node performs time calibration according to the time calibration information in the received time calibration beacon.

[0212] The slave node is connected to the lower layer node via a power line carrier communication link and / or a wireless communication link.

[0213] In this step S140, the role of the slave node is converted to the upper node of the lower node, and the lower node serves as the slave node in the above steps S110 to S130. When the lower node calibrates the time according to the timing information in the received time calibration beacon, it can be completed by executing the above steps S110 to S130.

[0214] In the time calibration method disclosed in the present invention, not only does the slave node need to receive the time calibration beacon from the upper node to perform its own time calibration, but after the slave node completes the time calibration, it also needs to assume the role of sending the time calibration beacon to the lower node, that is: each slave node will become the time calibration source for its lower node after completing its own time calibration. This process ensures that the time calibration information can be transmitted hierarchically along the network hierarchy, thereby forming a hierarchical transmission time calibration chain, and finally achieving time synchronization of all nodes in the power distribution network.

[0215] According to an embodiment of the present disclosure, the power distribution network further includes a terminal wireless node.

[0216] Figure 6 FIG. 1 is a schematic diagram showing a communication connection between an end wireless node and its parent node according to an embodiment of the present disclosure. Figure 6As shown, the terminal wireless node (three terminal wireless nodes are used as an example for exemplary description) is connected to its parent node (including a slave node or a master node in the power distribution network) through a wireless communication link. In a specific application scenario, the wireless communication link includes but is not limited to: a high-speed wireless HRF communication link.

[0217] Figure 7 A flow chart of another method for timing distribution network based on zero-crossing reference according to an embodiment of the present disclosure is shown. When the substation node is a slave node, in addition to steps S110 to S140 as described above, the timing method further includes the following step S150:

[0218] In step S150, after the parent node completes the time calibration, the time calibration period of the terminal wireless node is obtained according to the time error coefficient and the maximum time synchronization tolerance threshold of the terminal wireless node connected to the parent node; and the terminal wireless node is calibrated according to the time calibration period.

[0219] According to an embodiment of the present disclosure, the step of acquiring the timing period of the terminal wireless node according to the time error coefficient of the terminal wireless node connected to the parent node and the maximum time synchronization tolerance threshold comprises:

[0220] Obtain the time error coefficient of the terminal wireless node to form a time error coefficient set Q α , recorded as: Q α ={α1, α2, ... α n}; where n represents the number of the terminal wireless nodes, and the time error coefficient α of the i-th terminal wireless node i is the time interval T between two time calibrations performed by the parent node of the i-th terminal wireless node on the i-th terminal wireless node b , and the internal clock time error Δt of the i-th terminal wireless node after the two calibrations i , calculated by the following formula:

[0221] α i =Δt i / T b , where Δt i =|T i2 -T i1 |, T i1 The internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the first time calibration on the i-th terminal wireless node, T i2 The internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the second time calibration on the i-th terminal wireless node;

[0222] Obtain a maximum time synchronization tolerance threshold of the terminal wireless node.

[0223] The maximum time synchronization period of the terminal wireless node is calculated according to the maximum time synchronization tolerance threshold and the time error coefficient set to form a maximum time synchronization period set {T MAX_1 , T MAX_2 ,…T MAX_n}, where the maximum timing period T of the i-th terminal wireless node MAX_i =Δt MAX_i / α i , Δt MAX_i is the maximum time synchronization tolerance threshold of the i-th terminal wireless node.

[0224] Time slot allocation is performed according to the maximum timing cycle of the terminal wireless node to obtain the timing cycle of the terminal wireless node.

[0225] The terminal wireless node is time-synchronized according to the time-synchronization period.

[0226] According to an embodiment of the present disclosure, the time synchronization method further includes:

[0227] Determine the optimization goal:

[0228]

[0229] Among them, p c The power consumption generated by the parent node in calibrating the terminal wireless node; Δt c is the channel time occupied by the parent node to calibrate the terminal wireless node, β T is the threshold of the channel occupation ratio of the parent node to the terminal wireless node for timing calibration, T i is the time calibration period of the i-th terminal wireless node;

[0230] According to the optimization target, the time calibration period {T1, T2, ... T n};

[0231] The step of calibrating the terminal wireless node according to the calibration period includes:

[0232] The terminal wireless node is time-synchronized according to the optimized time-synchronization period.

[0233] The present invention discloses a time synchronization method based on the maximum clock tolerance period of the node applied to the terminal wireless node as described in step S150 above. By accurately calculating and utilizing the maximum clock tolerance period of each node for time synchronization, this method can avoid unnecessary frequent time synchronization operations, thereby reducing the energy consumption caused by time synchronization communications. This not only reduces the energy consumption of a single node, but also reduces the additional energy consumption caused by communication conflicts and retries by optimizing the overall communication mode of the network.

[0234] Figure 8 A flow chart of another method for timing a power distribution network based on a zero-crossing reference according to an embodiment of the present disclosure is shown, wherein the timing method is applied to a master node in a power distribution network, wherein the power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, wherein the multiple layers of nodes include a master node and a slave node, wherein the 0th layer node is a master node, and the nodes of other layers except the 0th layer node are slave nodes, wherein the master node is connected to the lower layer slave node via a power line carrier communication link and / or a wireless communication link, and the master node and the slave node are both provided with a zero-crossing detection circuit, as shown in FIG. Figure 8 As shown, the time calibration method includes the following steps S810-S820:

[0235] In step S810, time is adjusted according to a preset time adjustment method.

[0236] The preset time calibration method may be to obtain a high-precision time reference from a time reference source, such as GPS, NTP server or other high-precision clock, to ensure the accuracy and reliability of the time reference.

[0237] In step S820, a time calibration beacon is sent to the lower-level slave node to realize time synchronization of the lower-level slave node; the time calibration beacon contains time synchronization information, so that the lower-level slave node can perform time synchronization according to 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 slave node is located; wherein the time synchronization information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the zero-crossing time of the phase line where the master node is located, and the time value of the sending time of the time calibration beacon is timed by the local clock of the master node.

[0238] According to an embodiment of the present disclosure,

[0239] 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, and the first NTB time difference, the second NTB time difference, and the third NTB time difference correspond to three different phase lines respectively. In a specific example, the first NTB time difference corresponds to the A phase line, the second NTB time difference corresponds to the B phase line, and the third NTB time difference corresponds to the C phase line.

[0240] In addition, the time calibration beacon sent by the master node can not only be Figure 2 It can be received by the lower layer slave nodes of the first layer) shown in the figure, and can also be received by the slave nodes of other layers in the power distribution network. However, when the slave nodes of other layers are calibrating time, when the slave node being calibrated is in phase with its upper layer node, the time calibration can be completed by using only the time calibration information in the time calibration beacon sent by the upper layer node. Only when the slave node being calibrated is not in phase with its upper layer node, the time calibration can be completed in combination with the time calibration information in the time calibration beacon sent by the master node.

[0241] Fig. 9 FIG. 1 is a block diagram showing a timing device for a power distribution network based on a zero-crossing reference according to an embodiment of the present disclosure. Fig. 9 As shown, the timing device 900 is arranged at a slave node in a power distribution network, the power distribution network adopts a layered networking mode and includes multiple layers of nodes, the multiple layers of nodes include a master node and a slave node, wherein the 0th layer node is a master node, and the nodes of other layers except the 0th layer node are slave nodes, the slave node is connected to the upper layer node via 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 timing device 900 includes: an upper layer node time calibration beacon receiving module, which is configured to receive a time calibration beacon sent by the upper layer node after the upper layer node of the slave node completes the time calibration, the time calibration beacon contains timing information, and the timing information includes: the The time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the first zero-crossing time of the phase line where the upper node that sends the time calibration beacon is located, wherein the time value of the sending time of the time calibration beacon is timed by the local clock of the upper node that sends the time calibration beacon; an NTB time difference acquisition module, which is configured to obtain 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; and a slave node timing module, which is configured to perform timing on the slave node according to the timing 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.

[0242] According to an embodiment of the present disclosure, the first zero-crossing moment and the second zero-crossing moment are the same zero-crossing moment; or there is a preset relationship between the first zero-crossing moment and the second zero-crossing moment.

[0243] According to an embodiment of the present disclosure, the slave node is also connected to the lower node via a power line carrier communication link and / or a wireless communication link, and the timing device 900 further includes:

[0244] The slave node time calibration beacon sending module is configured to send a time calibration beacon to a lower-level node after the slave node completes time calibration, so that the lower-level node performs time calibration according to the time calibration information in the received time calibration beacon.

[0245] According to an embodiment of the present disclosure, 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 reception time of the time calibration beacon and the second zero crossing time of the phase line where the slave node is located includes:

[0246] Obtaining a time calibration NTB time difference according to the NTB time difference in the time calibration information, wherein the time calibration NTB time difference corresponds to the phase line where the slave node is located;

[0247] Calculate the time calibration beacon transmission delay time according to 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;

[0248] Calculate the calibration time corresponding to the reception time of the time calibration beacon according to the transmission delay time of the time calibration beacon and the time value of the sending time in the calibration information;

[0249] The time is calibrated using the calibration time corresponding to the reception time of the time calibration beacon.

[0250] According to an embodiment of the present disclosure, 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; 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 includes:

[0251] When the NTB time difference in the timing information includes the first NTB time difference, the second NTB time difference and the third NTB time difference, the NTB time difference in the timing information corresponding to the phase line where the slave node is located is used as the timing NTB time difference;

[0252] When the NTB time difference in the timing 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 that sends the time calibration beacon and the slave node are in-phase nodes, the NTB time difference in the timing information is used as the timing NTB time difference;

[0253] When the NTB time difference in the timing 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 that sends the time calibration beacon and the slave node are not in phase, obtain two NTB time differences in the time calibration beacon sent by the master node that correspond to the phase line where the slave node is located and the phase line where the upper node that sends the time calibration beacon is located, obtain the difference between the two NTB time differences, and subtract the difference from the NTB time difference in the timing information to obtain the timing NTB time difference.

[0254] According to an embodiment of the present disclosure, the time calibration beacon transmission delay time is calculated using the following formula:

[0255] T Intv =ΔT NTB-L +nT ABC -ΔT NTB ;

[0256] The calibration time corresponding to the reception time of the time calibration beacon is calculated using the following formula:

[0257] T P =T Intv +T c ;

[0258] Among them, T P represents the calibration time corresponding to the reception time of the time calibration beacon; T Intv represents the transmission delay time of the time calibration beacon; T c Indicates the time value of the sending time in the timing information; ΔT NTB-L 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; T ABC is the power frequency cycle; n is the number of power frequency cycles spanned by the time calibration beacon transmission, n≥0, ΔT NTB It is the time difference of the time calibration NTB.

[0259] According to an embodiment of the present disclosure, the power distribution network further includes a terminal wireless node, the terminal wireless node is connected to its parent node via a wireless communication link, and the parent node includes: a master node or a slave node in the power distribution network; the timing device 900 further includes: a terminal wireless node timing module, wherein the terminal wireless node timing module includes:

[0260] The timing cycle acquisition unit is configured to acquire the timing cycle of the terminal wireless node according to the time error coefficient and the maximum time synchronization tolerance threshold of the terminal wireless node connected to the parent node after the parent node completes the timing. The terminal wireless node timing unit is configured to perform timing on the terminal wireless node according to the timing cycle.

[0261] According to an embodiment of the present disclosure, the timing cycle acquisition unit includes:

[0262] The time error coefficient acquisition unit is configured to acquire the time error coefficient of the terminal wireless node to form a time error coefficient set Q α , recorded as: Q α ={α1, α2, ... α n}; where n represents the number of the terminal wireless nodes, and the time error coefficient α of the i-th terminal wireless node i is the time interval T between two time calibrations performed by the parent node of the i-th terminal wireless node on the i-th terminal wireless node b , and the internal clock time error Δt of the i-th terminal wireless node after the two calibrations i , calculated by the following formula:

[0263] α i =Δt i / T b , where Δt i =|T i2 -T i1 |, T i1 The internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the first time calibration on the i-th terminal wireless node, T i2 The internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the second time calibration on the i-th terminal wireless node.

[0264] The maximum time synchronization tolerance threshold acquisition unit is configured to acquire the maximum time synchronization tolerance threshold of the terminal wireless node.

[0265] A maximum timing cycle calculation unit is configured to calculate the maximum timing cycle of the terminal wireless node according to the maximum time synchronization tolerance threshold and the time error coefficient set to form a maximum timing cycle set Among them, the maximum timing period T of the i-th terminal wireless node MAX_i =Δt MAX_i / α i , Δt MAX_i is the maximum time synchronization tolerance threshold of the i-th terminal wireless node.

[0266] The terminal wireless node timing cycle acquisition unit is configured to perform time slot allocation according to the maximum timing cycle of the terminal wireless node to obtain the timing cycle of the terminal wireless node.

[0267] According to an embodiment of the present disclosure, the timing cycle acquisition unit further includes:

[0268] The optimization target determination unit is configured to determine the optimization target:

[0269]

[0270] Among them, p c The power consumption generated by the parent node in calibrating the terminal wireless node; Δt c is the channel time occupied by the parent node to calibrate the terminal wireless node, β T is the threshold of the channel occupation ratio of the parent node to the terminal wireless node for timing calibration, T i is the time calibration period of the i-th terminal wireless node;

[0271] The timing cycle optimization unit is configured to optimize the timing cycle {T1, T2, ...T n};

[0272] The step of calibrating the terminal wireless node according to the calibration period includes:

[0273] The terminal wireless node is time-synchronized according to the optimized time-synchronization period.

[0274] Fig.10 FIG. 2 shows a structural block diagram of another power distribution network timing device based on a zero-crossing reference according to an embodiment of the present disclosure. Fig.10As shown, the timing device 1000 is arranged at a master node in a power distribution network, the power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, the multiple layers of nodes include master nodes and slave nodes, wherein the 0th layer node is the master node, and the nodes of other layers except the 0th layer node are slave nodes, the master node is connected to the lower layer slave node via 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 timing device 1000 includes: a master node timing module, which is configured to perform timing according to a preset timing mode; a master node time calibration beacon transmitter The sending module is configured to send a time calibration beacon to a lower-level slave node to realize time calibration of the lower-level slave node; the time calibration beacon contains time calibration information, so that the lower-level slave node can perform time calibration according to the time calibration information in the time calibration beacon and the NTB time difference between the receiving time of the time calibration beacon and the zero-crossing time of the phase line where the slave node is located; wherein the time calibration information includes: the sending time of the time calibration beacon, and the NTB time difference between the sending time and the zero-crossing time of the phase line where the master node is located, and the sending time of the time calibration beacon is timed by the local clock of the master node.

[0275] According to an embodiment of the present disclosure,

[0276] 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, and the first NTB time difference, the second NTB time difference and the third NTB time difference correspond to three different phase lines respectively.

[0277] According to the technical solution provided by the embodiment of the present disclosure, when the upper node of the slave node in the power distribution network completes the time calibration, the slave node receives the time calibration beacon sent by its upper node, and the time calibration beacon contains the time calibration information, and the time calibration information includes: the sending time of the time calibration beacon, and the NTB time difference between the sending time and the first zero-crossing time of the phase line where the upper node that sends the time calibration beacon is located, and then 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 is obtained, and finally the slave node is calibrated 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.

[0278] By adopting the time synchronization method of the power distribution network based on the zero-crossing reference, that is, the slave node directly calibrates the time according to the time synchronization information of its direct upper node, rather than all slave nodes relying on the time synchronization information of the master node. This time synchronization method effectively reduces the communication delay and error accumulation caused by multi-level forwarding of time synchronization information. In addition, the transmission delay of the time synchronization information from the upper node to the slave node is determined based on the power frequency zero-crossing acquisition reference, making the transmission delay more accurate. In this way, each level of node can be adjusted based on the latest and most accurate time synchronization information, thereby ensuring the high consistency of the time of each node in the power distribution network, significantly improving the time synchronization accuracy, and effectively solving the problems of low time synchronization accuracy and poor reliability of each node in the power distribution network during time synchronization, and improving the reliability and stability of the power distribution network.

[0279] Fig.11 FIG. 1 shows a structural block diagram of a first electronic device according to an embodiment of the present disclosure. Fig.11 As shown, the first electronic device includes a first memory and a first processor; wherein, the first memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the first processor to implement the time synchronization method described in any of the above method embodiments applied to a slave node in a power distribution network.

[0280] Fig.12 FIG. 2 shows a structural block diagram of a second electronic device according to an embodiment of the present disclosure. Fig.12 As shown, the second electronic device includes a second memory and a second processor; wherein, the second memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the second processor to implement the time synchronization method described in any of the above method embodiments applied to the main node in the power distribution network.

[0281] Fig.13 FIG. 1 shows a structural diagram of a power distribution network timing system based on a zero-crossing reference according to an embodiment of the present disclosure. Fig.13 As shown, the timing system includes a slave node and a master node in the power distribution network ( Fig.13 Take one master node and thirteen slave nodes as an example for explanation), wherein the power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, wherein the multiple layers of nodes include master nodes and slave nodes, wherein the 0th layer node is the master node, and the other layer nodes except the 0th layer node are slave nodes, and the slave nodes are connected to the upper layer nodes through power line carrier communication links and / or wireless communication links, and the timing system includes slave nodes and master nodes in the power distribution network, and the master nodes and the slave nodes are both provided with zero-crossing detection circuits, wherein:

[0282] The slave node includes the time calibration device 900 as described in any one of the above items, or is implemented as the first electronic device as described above; and / or

[0283] The master node includes the time calibration device 1000 as described in any one of the above items, or is implemented as a second electronic device as described above.

[0284] The present disclosure also provides a chip, comprising a time calibration device as described in any one of the above device embodiments; 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 a time calibration method as described in any one of the above method embodiments.

[0285] The present disclosure also provides a computer-readable storage medium, which may be a computer-readable storage medium included in the electronic device or computer system in the above embodiment; or a computer-readable storage medium that exists independently and is not assembled into a device. The computer-readable storage medium stores one or more programs, and the programs are used by one or more processors to execute the time calibration method described in the present disclosure.

[0286] The present disclosure also provides a computer program product, including a computer program, wherein when the computer program is executed by a processor, the time calibration method described in any one of the present disclosure is implemented.

[0287] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present disclosure is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present disclosure (but not limited to) by each other.

Claims

1. A time calibration method for a power distribution network based on a zero-crossing reference, characterized in that: The timing method is applied to slave nodes in a power distribution network, the power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, the multiple layers of nodes include master nodes and slave nodes, wherein the 0th layer node is the master node, and the nodes of other layers except the 0th layer node are slave nodes, the master node and the slave node are both provided with a zero-crossing detection circuit, and the timing method includes: After the upper node of the slave node completes the time calibration, a time calibration beacon sent by the upper node is received, wherein the time calibration beacon contains the time calibration information, and the time calibration information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the first zero-crossing time of the phase line where the upper node sending the time calibration beacon is located, wherein the time value of the sending time of the time calibration beacon is timed by the local clock of the upper node sending the time calibration beacon; Obtaining 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; The slave node is timed according to the time calibration 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.

2. The time calibration method according to claim 1, characterized in that: The first zero-crossing time and the second zero-crossing time are the same zero-crossing time; or There is a preset relationship between the first zero-crossing time and the second zero-crossing time.

3. The time calibration method according to claim 1, characterized in that: The time calibration method also includes: After the slave node completes the time calibration, it sends a time calibration beacon to the lower-level node, so that the lower-level node performs time calibration according to the time calibration information in the received time calibration beacon.

4. The time calibration method according to claim 1, characterized in that: 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 reception time of the time calibration beacon 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, wherein the time calibration NTB time difference corresponds to the phase line where the slave node is located; Calculate the time calibration beacon transmission delay time according to 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; Calculate the calibration time corresponding to the reception time of the time calibration beacon according to the transmission delay time of the time calibration beacon and the time value of the sending time in the calibration information; The time is calibrated using the calibration time corresponding to the reception time of the time calibration beacon.

5. The time calibration method according to claim 4, characterized in that: in, 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; 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 includes: When the NTB time difference in the timing information includes the first NTB time difference, the second NTB time difference and the third NTB time difference, the NTB time difference in the timing information corresponding to the phase line where the slave node is located is used as the timing NTB time difference; When the NTB time difference in the timing 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 that sends the time calibration beacon and the slave node are in-phase nodes, the NTB time difference in the timing information is used as the timing NTB time difference; When the NTB time difference in the timing 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 that sends the time calibration beacon and the slave node are not in phase, obtain two NTB time differences in the time calibration beacon sent by the master node that correspond to the phase line where the slave node is located and the phase line where the upper node that sends the time calibration beacon is located, obtain the difference between the two NTB time differences, and subtract the difference from the NTB time difference in the timing information to obtain the timing NTB time difference.

6. The time calibration method according to claim 5, characterized in that: The time calibration beacon transmission delay time is calculated using the following formula: T Intv =ΔT NTB-L +nT ABC -ΔT NTB ; 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 ; Among them, T P represents the calibration time corresponding to the reception time of the time calibration beacon; T Intv represents the transmission delay time of the time calibration beacon; T c Indicates the time value of the sending time in the timing information; ΔT NTB-L 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; T ABC is the power frequency cycle; n is the number of power frequency cycles spanned by the time calibration beacon transmission, n≥0, ΔT NTB It is the time difference of the time calibration NTB.

7. The time calibration method according to claim 1, characterized in that: The power distribution network also includes a terminal wireless node, the terminal wireless node is connected to its parent node via a wireless communication link, and the parent node includes: a master node or a slave node in the power distribution network; the time synchronization method also includes: When the parent node completes the time calibration, the time calibration period of the terminal wireless node is obtained according to the time error coefficient of the terminal wireless node connected to the parent node and the maximum time synchronization tolerance threshold; The terminal wireless node is time-calibrated according to the time-calibration period.

8. The time calibration method according to claim 7, characterized in that: The step of acquiring the timing period of the terminal wireless node according to the time error coefficient of the terminal wireless node connected to the parent node and the maximum time synchronization tolerance threshold comprises: Obtain the time error coefficient of the terminal wireless node to form a time error coefficient set Q α , recorded as: Q α ={α1, α2, ... α n }; where n represents the number of the terminal wireless nodes, and the time error coefficient α of the i-th terminal wireless node i is the time interval T between two time calibrations performed by the parent node of the i-th terminal wireless node on the i-th terminal wireless node b , and the internal clock time error Δt of the i-th terminal wireless node after the two calibrations i , calculated by the following formula: α i =Δt i / T b , where Δt i =|T i2 -T i1 |, T i1 is the internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the first time calibration on the i-th terminal wireless node, T i2 The internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the second time calibration on the i-th terminal wireless node; Obtain the maximum time synchronization tolerance threshold of the terminal wireless node; calculate the maximum timing cycle of the terminal wireless node according to the maximum time synchronization tolerance threshold and the time error coefficient set to form a maximum timing cycle set {T MAX_1 , T MAX_2 ,…T MAX_n }, where the maximum timing period T of the i-th terminal wireless node MAX_i =Δt MAX_i / α i , Δt MAX_i is the maximum time synchronization tolerance threshold of the i-th terminal wireless node; Time slot allocation is performed according to the maximum timing cycle of the terminal wireless node to obtain the timing cycle of the terminal wireless node.

9. The time calibration method according to claim 8, characterized in that: The time calibration method also includes: Determine the optimization goal: Among them, p c The power consumption generated by the parent node in calibrating the terminal wireless node; Δt c is the channel time occupied by the parent node to calibrate the terminal wireless node, β T is the threshold of the channel occupation ratio of the parent node to the terminal wireless node for timing calibration, T i is the time calibration period of the i-th terminal wireless node; According to the optimization target, the timing period {T1, T2, ...T n }; The step of calibrating the terminal wireless node according to the calibration period includes: The terminal wireless node is time-synchronized according to the optimized time-synchronization period.

10. A time calibration method for a power distribution network based on a zero-crossing reference, characterized in that: The timing method is applied to a master node in a power distribution network, the power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, the multiple layers of nodes include a master node and a slave node, wherein the 0th layer node is a master node, and other layer nodes except the 0th layer node are slave nodes, the master node and the slave node are both provided with a zero-crossing detection circuit, and the timing method includes: Perform time calibration according to the preset time calibration method; A time calibration beacon is sent to the lower-level slave node to realize time calibration of the lower-level slave node; the time calibration beacon contains time calibration information, so that the lower-level slave node can perform time calibration according to the time calibration 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 calibration information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the zero-crossing time of the phase line where the master node is located, and the time value of the sending time of the time calibration beacon is timed by the local clock of the master node.

11. The time calibration method according to claim 10, characterized in that: in, 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, and the first NTB time difference, the second NTB time difference and the third NTB time difference correspond to three different phase lines respectively.

12. A time calibration device for a power distribution network based on a zero-crossing reference, characterized in that: The timing device is arranged at a slave node in a power distribution network. The power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes. The multiple layers of nodes include a master node and a slave node. The 0th layer node is a master node, and the nodes of other layers except the 0th layer node are slave nodes. The master node and the slave node are both provided with a zero-crossing detection circuit. The timing device includes: The upper node time calibration beacon receiving module is configured to receive the time calibration beacon sent by the upper node after the upper node of the slave node completes the time calibration, wherein the time calibration beacon contains the time calibration information, and the time calibration information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the first zero-crossing time of the phase line where the upper node sending the time calibration beacon is located, wherein the time value of the sending time of the time calibration beacon is timed by the local clock of the upper node sending the time calibration beacon; An NTB time difference acquisition module is configured to acquire an NTB time difference between a reception time of the time calibration beacon and a second zero-crossing time of the phase line where the slave node is located; The slave node timing module is configured to perform timing on the slave node according to the timing 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.

13. The time setting device according to claim 12, characterized in that: The time calibration device also includes: The slave node time calibration beacon sending module is configured to send a time calibration beacon to a lower-level node after the slave node completes time calibration, so that the lower-level node performs time calibration according to the time calibration information in the received time calibration beacon.

14. The time setting device according to claim 12, characterized in that: The power distribution network also includes a terminal wireless node, which is connected to its parent node via a wireless communication link, and the parent node includes: a master node or a slave node in the power distribution network; the timing device also includes a terminal wireless node timing module, wherein the terminal wireless node timing module includes: A timing cycle acquisition unit is configured to acquire the timing cycle of the terminal wireless node according to the time error coefficient of the terminal wireless node connected to the parent node and the maximum time synchronization tolerance threshold after the parent node completes the timing. The terminal wireless node timing unit is configured to perform timing calibration on the terminal wireless node according to the timing calibration period.

15. The time setting device according to claim 14, characterized in that: The timing cycle acquisition unit comprises: The time error coefficient acquisition unit is configured to acquire the time error coefficient of the terminal wireless node to form a time error coefficient set Q α , recorded as: Q α ={α1, α2, ... α n }; where n represents the number of the terminal wireless nodes, and the time error coefficient α of the i-th terminal wireless node i is the time interval T between two time calibrations performed by the parent node of the i-th terminal wireless node on the i-th terminal wireless node b , and the internal clock time error Δt of the i-th terminal wireless node after the two calibrations i , calculated by the following formula: α i =Δt i / T b , where Δt i =|T i2 -T i1 |, T i1 is the internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the first time calibration on the i-th terminal wireless node, T i2 The internal clock time of the i-th terminal wireless node after the parent node of the i-th terminal wireless node performs the second time calibration on the i-th terminal wireless node; A maximum time synchronization tolerance threshold acquisition unit is configured to acquire a maximum time synchronization tolerance threshold of the terminal wireless node; The maximum timing cycle calculation unit is configured to calculate the maximum timing cycle of the terminal wireless node according to the maximum time synchronization tolerance threshold and the time error coefficient set to form a maximum timing cycle set {T MAX_1 , T MAX_2 ,…T MAX_n }, where the maximum timing period T of the i-th terminal wireless node MAX_i =Δt MAX_i / α i , Δt MAX_i is the maximum time synchronization tolerance threshold of the i-th terminal wireless node; The terminal wireless node timing cycle acquisition unit is configured to perform time slot allocation according to the maximum timing cycle of the terminal wireless node to obtain the timing cycle of the terminal wireless node.

16. The time setting device according to claim 15, characterized in that: The timing cycle acquisition unit also includes: The optimization target determination unit is configured to determine the optimization target: Among them, p c The power consumption generated by the parent node in calibrating the terminal wireless node; Δt c is the channel time occupied by the parent node to calibrate the terminal wireless node, β T is the threshold of the channel occupation ratio of the parent node to the terminal wireless node for timing calibration, T i is the time calibration period of the i-th terminal wireless node; The timing cycle optimization unit is configured to optimize the timing cycle {T1, T2, ...T n }; The step of calibrating the terminal wireless node according to the calibration period includes: The terminal wireless node is time-synchronized according to the optimized time-synchronization period.

17. A time calibration device for a power distribution network based on a zero-crossing reference, characterized in that: The timing device is arranged at a master node in a power distribution network. The power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes. The multiple layers of nodes include master nodes and slave nodes. The 0th layer node is the master node, and the nodes of other layers except the 0th layer node are slave nodes. The master node and the slave node are both provided with a zero-crossing detection circuit. The timing device includes: The master node timing module is configured to perform timing according to a preset timing method; The master node time calibration beacon sending module is configured to send time calibration beacons to lower-level slave nodes to implement time calibration of the lower-level slave nodes; the time calibration beacon contains time calibration information so that the lower-level slave nodes can perform time calibration based on the time calibration 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 slave node is located; wherein the time calibration information includes: the time value of the sending time of the time calibration beacon, and the NTB time difference between the sending time and the zero-crossing time of the phase line where the master node is located, and the time value of the sending time of the time calibration beacon is based on the local clock of the master node.

18. A first electronic device, characterized in that: It comprises a first memory and a first processor; wherein the first memory is used to store computer instructions, wherein the computer instructions are executed by the first processor to implement the time calibration method according to any one of claims 1 to 9.

19. A second electronic device, characterized in that: It comprises a second memory and a second processor; wherein the second memory is used to store computer instructions, wherein the computer instructions are executed by the second processor to implement the time calibration method according to any one of claims 10 to 11.

20. A time calibration system for a power distribution network based on a zero-crossing reference, characterized in that: The power distribution network adopts a hierarchical networking mode and includes multiple layers of nodes, wherein the multiple layers of nodes include master nodes and slave nodes, wherein the 0th layer node is the master node, and the nodes of other layers except the 0th layer node are slave nodes, and the timing system includes the slave nodes and the master nodes in the power distribution network, and the master nodes and the slave nodes are both provided with a zero-crossing detection circuit, wherein: The slave node comprises the time calibration device according to any one of claims 12 to 16, or is implemented as the first electronic device according to claim 18; and / or The master node includes the time calibration device according to claim 17, or is implemented as the second electronic device according to claim 19.

21. A chip, characterized in that: A time calibration device comprising any one of claims 12 to 17; 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 calibration method according to any one of claims 1 to 11.

22. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the computer instructions are executed by a processor, the time calibration method according to any one of claims 1 to 11 is implemented.

23. A computer program product comprising computer instructions, characterized in that When the computer instructions are executed by a processor, the time calibration method according to any one of claims 1 to 11 is implemented.

Images