A method for identifying substation topology based on low voltage topology unit

Abstract

The present invention discloses a substation topology identification method based on low-voltage topology units, comprising: a fusion topology unit controls low-voltage topology units to send characteristic current signals in sequence, and the low-voltage topology units receive and identify the characteristic current signals in real time and then report identification record data; the fusion topology unit generates a first topology structure according to the identification record data of all low-voltage topology units, and regularly monitors the abnormal state of each low-voltage topology unit through the first topology structure; if the proportion of the number of low-voltage topology units in the abnormal state is lower than a first proportion threshold, the abnormal state type of the low-voltage topology unit is analyzed, and the topology structure is updated according to the abnormal state type; if the proportion of the number of low-voltage topology units in the abnormal state exceeds the first proportion threshold, global topology identification is performed to obtain a second topology structure, the second topology structure is compared with the first topology structure, a changed node is obtained, and the topology structure is updated according to the changed node type.

Description

Technical Field

[0001] The present invention relates to the technical field of substation topology identification, and in particular to a substation topology identification method based on a low-voltage topology unit. Background Art

[0002] Substation topology identification refers to the process of determining the topological structure and relationship between various electrical equipment in the power system by analyzing the equipment distribution and connection relationship of the distribution station area (or distribution network) in the power system, and constructing a network model of the entire distribution station area.

[0003] The topology information of traditional low-voltage lines in substations often relies on manual records or static design drawings. The data is incomplete or inaccurate, and it is difficult to reflect the actual line connection relationship. With the line transformation or user access changes, the topology information cannot be dynamically updated. The existing substation topology identification deploys low-voltage topology units at key nodes of the substation low-voltage lines, sends and receives characteristic current signals in real time, and can identify the connection relationship between nodes and draw the actual topology structure.

[0004] However, the actual topology of low-voltage lines often changes (such as adding new users, line modifications, equipment replacement, etc.). When the low-voltage topology unit detects a topology change, it is often necessary to re-identify the global topology. Since the existing technology relies on the fixed sending and receiving of static characteristic current signals, it does not dynamically update the judgment based on the actual cause of the change, resulting in reduced recognition efficiency.

[0005] In the process of topology update and identification, some local interference (such as signal noise, transient electromagnetic interference) or intermittent failures (such as short-term node disconnection, weak signal) may cause inaccurate topology identification. Existing technologies usually directly adopt the method of re-identifying the global topology, which fails to make full use of the existing topology information, increases the burden on the system, and reduces the update efficiency. In addition, the existing technology lacks targeted processing for different types of topological structure changes (such as adding nodes, removing nodes, and changing nodes in state), resulting in insufficient accuracy and efficiency of topology update identification.

[0006] In view of the above problems in the prior art, the purpose of the present invention is to design a substation topology identification method based on low-voltage topology units. Summary of the invention

[0007] In view of this, an object of the present invention is to propose a substation topology identification method based on a low voltage topology unit, which can solve the above-mentioned problem.

[0008] The present invention provides a method for identifying a substation topology based on a low-voltage topology unit, and a system for identifying a substation topology based on a low-voltage topology unit, comprising: A plurality of low-voltage topology units are respectively deployed in nodes of the low-voltage line and are used to generate and collect characteristic current signals in the low-voltage line. The plurality of low-voltage topology units form a multi-level topology structure. The fusion topology unit is deployed at the distribution transformer of the low-voltage line to control the low-voltage topology unit and perform topology analysis and identification based on the characteristic current signals collected by the low-voltage topology unit. The method comprises: The fusion topology unit controls the low-voltage topology unit to send characteristic current signals in sequence, and the low-voltage topology unit receives and identifies the characteristic current signals in real time and then reports the identification and recording data; The fusion topology unit generates a first topology structure according to the identification record data of all low-voltage topology units, and regularly monitors the abnormal state of each low-voltage topology unit through the first topology structure; If the proportion of the number of low-voltage topology units in the abnormal state is lower than the first proportion threshold, analyzing the abnormal state type of the low-voltage topology unit, and updating the topology structure according to the abnormal state type; If the proportion of low-voltage topology units in abnormal state exceeds the first proportion threshold, global topology identification is performed to obtain a second topology structure, the second topology structure is compared with the first topology structure to obtain a changed node, and the topology structure is updated according to the changed node type.

[0009] Furthermore, the fusion topology unit controls the low-voltage topology unit to send characteristic current signals in sequence, and the low-voltage topology unit receives and identifies the characteristic current signals in real time and then reports the identification record data including: The fusion topology unit sends control commands to each low-voltage topology unit in turn through broadband carrier communication; The low voltage topology unit generates a characteristic sequence code bit according to the control command to generate and send a characteristic current signal, and stores default information in any code bit; Each low-voltage topology unit samples and identifies the characteristic current signal in real time. If the identification is successful, the characteristic sequence information of the characteristic current signal and the physical location of the node are reported.

[0010] Furthermore, each low-voltage topology unit samples and identifies characteristic current signals in real time, including: Each low-voltage topology unit samples characteristic current signals, and starts identification when more than N groups of characteristic current signals are present continuously; During identification, if there are more than N+1 groups with characteristic current signals, they are marked as 1 and matched with the default information. If the match is successful, the identification is successful.

[0011] Further, the fusion topology unit generates a first topology structure according to the identification record data of all low-voltage topology units, including: After all low-voltage topology units have executed control commands and reported identification record data, the fusion topology unit counts the number of identifications of each low-voltage topology unit; The fusion topology unit recursively sorts out the hierarchical topological structure of each route according to the number of recognition times from low to high, and forms a first topological structure by integrating the hierarchical topological structure of each route.

[0012] Further, the periodic monitoring of the abnormal state of each low-voltage topology unit by the first topology structure includes: By each low-voltage topology unit periodically sending a heartbeat signal to an adjacent low-voltage topology unit according to the first topology structure; If a low-voltage topology unit does not receive the heartbeat signal sent by a neighboring low-voltage topology unit, it records that the state of the neighboring low-voltage topology unit is abnormal and broadcasts it to the fusion topology unit.

[0013] Further, if the proportion of the low-voltage topology units in the abnormal state is lower than the first proportion threshold, analyzing the abnormal state type of the low-voltage topology unit, and updating the topology structure according to the abnormal state type includes: The fusion topology unit initiates several heartbeat signals to the low-voltage topology unit in the abnormal state, and records the response success rate R. If the response success rate R ≥ 60%, the abnormal state is classified as instantaneous interference, and the topology node corresponding to the low-voltage topology unit is retained; If 20%≤response success rate R<60%, the abnormal state is classified as an intermittent fault, and the topology node corresponding to the low-voltage topology unit is retained. If the response success rate R<20%, neighbor collaborative verification is performed.

[0014] Furthermore, the steps of neighbor collaborative verification are as follows: Initiate several heartbeat signals to the low-voltage topology unit in the abnormal state through the adjacent low-voltage topology unit; The packet loss rate PLR ​​and delay L of the heartbeat signal of all adjacent low-voltage topology units are collected, and the communication quality index Q is calculated by the packet loss rate PLR ​​and delay L of the heartbeat signal. The calculation formula of the communication quality index Q is: , in, is the packet loss rate of the heartbeat signal The weight of Delay L The weight of If the communication quality index Q>0.8, the abnormal state is classified as a communication failure, and the topology node corresponding to the low-voltage topology unit is removed, otherwise the characteristic current signal verification is performed.

[0015] Further, the steps of verifying the characteristic current signal are as follows: A special verification sequence is sent to the low-voltage topology unit in the abnormal state, requiring all low-voltage topology units in the branch where the low-voltage topology unit in the abnormal state is located to feedback the signal strength within the window period; Calculate signal attenuation by feedback signal strength , if the average signal attenuation >30dB, the abnormal state is classified as a physical line interruption, and the topology node corresponding to the low-voltage topology unit is removed.

[0016] Furthermore, the average signal attenuation The calculation formula is as follows: , , in, is the attenuation of a single path, is the signal strength sent by the low-voltage topology unit end of the branch, is the signal strength received by the fusion topology unit, i represents the i-th signal branch, and M represents the number of signal branches.

[0017] Further, if the proportion of the number of low-voltage topology units in the abnormal state exceeds the first proportion threshold, global topology identification is performed to obtain a second topology structure, the second topology structure is compared with the first topology structure to obtain a changed node, and the topology structure is updated according to the changed node type, including: If the changed node is a newly added node, the characteristic current signal of the newly added node is verified, and after the verification is passed, it is updated to the topology structure; If the changed node is a removed node, a number of heartbeat signals are sent to the removed node through the neighboring nodes of the removed node. If there is feedback, it is temporarily disconnected and the changed node is retained. Otherwise, the changed node is removed. If the changed node is a state-changed node, the abnormal state type of the changed node is analyzed, and the topology structure is updated according to the abnormal state type.

[0018] Beneficial effects of the present invention: First, by sending and receiving characteristic current signals, the physical connection relationship between low-voltage topology units can be clearly identified. The characteristic current signals can timely capture changes such as new nodes and wiring changes, and accurately reflect the actual connection of the network.

[0019] Second, by integrating the topology unit to aggregate and analyze the identification data of the low-voltage topology unit, the overall network model of the substation (i.e., the first topology structure) can be generated to ensure the topology is accurate. The monitoring process relies on the logical relationship of the first topology structure to quickly discover and lock abnormal nodes and ensure the stability of network operation.

[0020] Third, by judging the proportion of low-voltage topological units in abnormal states, the topology is updated in a classified manner for local abnormal problems (such as transient interference, intermittent faults, communication problems, etc.) without triggering global topology re-identification, reducing the system's computing and communication burden. Combined with the abnormal state type (such as transient interference processing, neighbor collaborative verification, characteristic current signal verification, etc.), the topology structure can be quickly updated to ensure efficient system response.

[0021] Fourth, when the proportion of nodes in abnormal state is high (for example, when it exceeds the threshold, it may involve multiple regional devices or trunk line problems), the latest second topology structure is obtained by performing global topology identification, and the original structure is completely replaced. The comparison between the first topology and the second topology can accurately locate the changed nodes, clarify the scope of the topology change, and then update the topology according to the type of changed nodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a flow chart of the method of embodiment 2.

[0024] Figure 2 This is a diagram of the identification record structure of the second embodiment.

[0025] Figure 3 This is the first topological structure diagram of the second embodiment. DETAILED DESCRIPTION

[0026] To facilitate understanding by those skilled in the art, the structure of the present invention is now further described in detail with reference to the embodiments and the accompanying drawings. It should be understood that the steps mentioned in the present embodiment, unless otherwise specified in their order, can be adjusted in order according to actual needs, and can even be executed simultaneously or partially simultaneously.

[0027] Embodiment 1 Embodiment 1 provides a substation topology identification system based on a low voltage topology unit, including: A plurality of low-voltage topology units are respectively deployed in nodes of the low-voltage line and are used to generate and collect characteristic current signals in the low-voltage line. The plurality of low-voltage topology units form a multi-level topology structure. The fusion topology unit is deployed at the distribution transformer of the low-voltage line to control the low-voltage topology unit and perform topology analysis and identification based on the characteristic current signals collected by the low-voltage topology unit. In this embodiment, a low-voltage topology unit LTU (Low-voltage Topology Unit) that supports non-stop construction is installed in the three-level low-voltage lines in the substation area (low-voltage feeder switch, branch box outlet switch, meter box incoming switch). After the low-voltage topology unit LTU is installed, it automatically registers to the broadband carrier communication network and actively reports to the fusion topology unit TTU (Terminal Topology Unit).

[0028] The internal circuit of the low-voltage topology unit is designed with a characteristic current generating module, which is a constant resistance load and can be used to generate a characteristic current signal. The internal circuit of the low-voltage topology unit is designed with a characteristic current receiving module, which samples the characteristic current signal on the transmission frequency band in real time.

[0029] Embodiment 2 like Figure 1 As shown, embodiment 2 provides a method for identifying a substation topology based on a low voltage topology unit, including: The S1 fusion topology unit controls the low-voltage topology unit to send characteristic current signals in sequence. The low-voltage topology unit receives and identifies the characteristic current signals in real time and then reports the identification and recording data. The S101 fusion topology unit sends control commands to each low-voltage topology unit in turn through broadband carrier communication; S102 low voltage topology unit generates and sends characteristic current signals based on characteristic sequence code positions according to control commands, and stores default information in any code position; Furthermore, before this step you need to execute: If other communication frequency bands exist on the current low-voltage line, the low-voltage topology unit sends the characteristic current signal at the second frequency according to the control command.

[0030] In this step, broadband carrier communication HPLC uses low-voltage power lines as the communication medium to achieve low-voltage power users' power information aggregation, transmission, and interactive communication. It mainly adopts orthogonal frequency division multiplexing, plug-and-play based on IPV6, node management and other technologies, breaking through the bottlenecks of communication capacity, stability, reliability and anti-interference ability in traditional power line carrier communication. The communication frequency band is from 0.7MHz to 12MHz, and the communication rate is increased to 2-10Mbps.

[0031] The first frequency can be 833.3Hz (settable), and a characteristic current signal is sent (high level and low level pulse width can be set). When sending a waveform sequence, 60ms is a group, and 10 groups are a characteristic sequence code position. At a code position, the default information carried by the characteristic waveform is controlled according to whether the characteristic current signal is sent or not. The default information can be [0xAAE9, 0xD577, 0xCC95, 0xB36B].

[0032] Since the intelligent meter reading in the substation also adopts broadband carrier communication HPLC, the carrier communication frequency band used by the low-voltage topology identification needs to be avoided with the intelligent meter reading in the substation to avoid conflict.

[0033] S103: Each low voltage topology unit samples and identifies the characteristic current signal in real time. If the identification is successful, the characteristic sequence information of the characteristic current signal and the physical location of the node are reported.

[0034] S1031 Each low-voltage topology unit samples characteristic current signals, and starts identification when more than N groups of characteristic current signals are present continuously; During S1032 identification, if more than N+1 groups have characteristic current signals, they are marked as 1 and matched with the default information. If the match is successful, the identification is successful.

[0035] In this step, 60ms is a group, and the characteristic current signal is marked as 1. If there are more than 6 groups of characteristic current signals in a row, the recognition is turned on. During recognition, 10 consecutive groups are a characteristic sequence code bit. If there are more than 7 groups with characteristic current, the code bit is 1, otherwise it is 0. After the characteristic information is recognized, it is matched bit by bit with the default information [0xAAE9, 0xD577, 0xCC95, 0xB36B]. If the matching code bit is successful, the recognition is successful. The mark "1" is a preliminary detection of the characteristic current signal, which is used to determine the existence of the signal; and the matching code bit is to further verify the accuracy and uniqueness of the signal to ensure that the signal comes from the target low-voltage topology unit. The process of matching the code bit can effectively filter interference signals and improve the reliability and accuracy of recognition.

[0036] The S2 fusion topology unit generates a first topology structure according to the identification record data of all low-voltage topology units, and regularly monitors the abnormal state of each low-voltage topology unit through the first topology structure; S201: After all low-voltage topology units have executed the control command and reported the identification record data, the fusion topology unit counts the number of identifications of each low-voltage topology unit; S202: The fusion topology unit recursively sorts out the hierarchical topological structure of each route according to the number of identifications from low to high, and forms a first topological structure by integrating the hierarchical topological structure of each route.

[0037] In this step, if Figure 2 , Figure 3As shown in the figure, only when all low-voltage topology units (LTU1~LTU17) complete the characteristic current sending and identification tasks can all nodes in the substation be included in the topological relationship. If a low-voltage topology unit fails to execute the command or report the identification record, it may cause omissions in the topological relationship and fail to reflect the complete physical structure of the substation. The fusion topology unit TTU will count the number of identifications of each low-voltage topology unit. The number of identifications reflects the propagation level of the characteristic current signal in the topological structure: the identification number of the upper node is higher because it is located upstream of the signal propagation path, and the identification number of the lower node is lower because it is located downstream of the signal propagation path. In this way, the hierarchical relationship on each line can be gradually sorted out, and the physical connection order of the nodes can be clarified.

[0038] S203: each low-voltage topology unit periodically sends a heartbeat signal to an adjacent low-voltage topology unit according to the first topology structure; S204: If a low-voltage topology unit does not receive a heartbeat signal sent by a neighboring low-voltage topology unit, the abnormality of the neighboring low-voltage topology unit is recorded and broadcasted to the fusion topology unit; In this step, each low-voltage topology unit can communicate with other low-voltage topology units through broadband carrier communication. The first topology structure is a physical connection relationship of the substation generated based on characteristic current identification, which clarifies the upstream, downstream and adjacent relationships of each low-voltage topology unit. In particular, in large-scale low-voltage power grids, if the topology structure is updated every time by sending a control signal through the fusion topology unit, it takes a lot of time. Therefore, based on the first topology structure, the low-voltage topology unit can accurately send a heartbeat signal to its neighboring node. The heartbeat signal is a lightweight data packet that usually contains the identification information and status information of the node. If a node does not send a heartbeat signal, it may indicate that the node has a fault (such as equipment disconnection, power line interruption, etc.). If a node is disconnected or restored, the heartbeat signal mechanism can reflect these changes in time. Since the broadband carrier communication network usually adopts a tree structure, if the intermediate node fails, it may cause the inability to report abnormal information step by step. Therefore, the abnormal information is reported by broadcasting, which is used for the subsequent fusion topology unit to dynamically update part of the topology structure and maintain the accuracy of the topological relationship.

[0039] S3: if the proportion of the number of low-voltage topology units in the abnormal state is lower than the first proportion threshold, analyze the abnormal state type of the low-voltage topology unit, and update the topology structure according to the abnormal state type; In this step, when the proportion of low-voltage topology units in abnormal state is less than the threshold, the scope of the problem is usually small and localized, which may be caused by the following reasons: communication interference in a specific node, hardware abnormality or temporary failure, signal attenuation in a branch node, neighborhood interference, etc. In this case, the problem is solved by analyzing the abnormal nodes one by one and updating their status, concentrating resources to handle abnormal nodes, without the need for global update, and low resource consumption.

[0040] S301 initiates several heartbeat signals to the low-voltage topology unit in the abnormal state through the fusion topology unit, records the response success rate R, and if the response success rate R≥60%, the abnormal state is classified as instantaneous interference, and the topology node corresponding to the low-voltage topology unit is retained; In this step, the low-voltage topology unit has a high response success rate, indicating that the communication link is basically normal. The problem may be caused by short-term interference or fluctuations in the broadband carrier network. The topology node corresponding to the low-voltage topology unit can be marked as "normal" and does not need to be removed from the topology structure. In the traditional topology update process, a node may be mistakenly removed due to a single abnormal communication failure, resulting in an error in the topology structure. By initiating multiple heartbeat signals and counting the success rate, unnecessary changes to the topology structure due to short-term abnormal effects can be avoided.

[0041] S302: If 20%≤response success rate R<60%, the abnormal state is classified as an intermittent fault, and the topology node corresponding to the low-voltage topology unit is retained. If the response success rate R<20%, neighbor collaborative verification is performed; In this step, the low-voltage topology unit response success rate is low but not zero, indicating that the low-voltage topology unit may have hardware problems or slight communication interference, resulting in its unstable state. The low-voltage topology unit remains in the topology, but its status is marked as "intermittent failure". The fusion topology unit can include the low-voltage topology unit in the maintenance plan and issue maintenance tasks. If these nodes are removed without distinguishing the reasons, it is easy to misjudge and cause errors in the network topology. If they are blindly retained, it may affect the connection stability of the entire topology structure. Therefore, neighbor collaborative verification is continued.

[0042] Neighbor collaborative verification, specifically: Initiate several heartbeat signals to the low-voltage topology unit in the abnormal state through the adjacent low-voltage topology unit; The packet loss rate PLR ​​and delay L of the heartbeat signal of all adjacent low-voltage topology units are collected, and the communication quality index Q is calculated by the packet loss rate PLR ​​and delay L of the heartbeat signal. The calculation formula of the communication quality index Q is: , in, is the packet loss rate of the heartbeat signal The weight of Delay L The weight of If the communication quality index Q>0.8, the abnormal state is classified as a communication failure, and the topology node corresponding to the low-voltage topology unit is removed, otherwise the characteristic current signal verification is performed; In this step, the adjacent low-voltage topology unit can be a low-voltage topology unit within a 3-hop range. The response success rate is extremely low, and the neighbor collaborative verification shows that the communication quality around it is poor, indicating that the problem may be caused by a communication failure. Temporarily remove the connection relationship of the node from the topology, but retain its physical location information. The fusion topology unit can include the node in the maintenance plan and issue maintenance tasks. The introduction of communication quality indicators provides a quantitative classification standard based on packet loss rate and latency for abnormal nodes, which can effectively distinguish between faults caused by communication interference (such as signal attenuation, noise interference) and hardware-level or line-level faults (such as circuit breakage or equipment damage).

[0043] Characteristic current signal verification, specifically: A special verification sequence is sent to the low-voltage topology unit in the abnormal state, requiring all low-voltage topology units in the branch where the low-voltage topology unit in the abnormal state is located to feedback the signal strength within the window period; Calculate signal attenuation by feedback signal strength , if the average signal attenuation >30dB, the abnormal state is classified as a physical line interruption, and the topology node corresponding to the low-voltage topology unit is removed; Specifically, the average signal attenuation The calculation formula is as follows: , , in, is the attenuation of a single path, is the signal strength sent by the low-voltage topology unit end of the branch, is the signal strength received by the fusion topology unit, i represents the i-th signal branch, and M represents the number of signal branches.

[0044] In this step, the characteristic current signal verification shows that the signal attenuation of the node is too high, indicating that the line may be physically disconnected or have serious impedance problems. In the topology, the topology node status corresponding to the low-voltage topology unit is marked as "line physical interruption". Physical line interruption (such as circuit break) is an anomaly that has a significant impact on the network topology. The node and its branch are removed from the topology structure to avoid affecting the communication of other nodes. The fusion topology unit can include the node in the maintenance plan and issue maintenance tasks.

[0045] S4: If the proportion of the number of low-voltage topology units in the abnormal state exceeds the first proportion threshold, global topology identification is performed to obtain a second topology structure, the second topology structure is compared with the first topology structure to obtain a changed node, and the topology structure is updated according to the type of the changed node.

[0046] In this step, when the proportion of low-voltage topology units in abnormal state exceeds the threshold, the coverage of the problem may be large, for example: the distribution of related nodes shows a trend, such as regional communication failure or trunk line disconnection, which may involve state changes caused by adding or removing multiple nodes (for example, new equipment access leads to structural changes, or the entire branch fails). At this time, it is necessary to fully re-analyze the system through global topology identification to obtain an accurate second topology structure, and it is necessary to compare and verify it according to the first topology structure to ensure the accuracy of the update of the changed nodes, and at the same time, update the topology according to the specific structural type of the changed nodes.

[0047] S401: If the changed node is a newly added node, verify the characteristic current signal of the newly added node, and update it to the topology structure after passing the verification; In this step, the newly added node may be a device that is not authorized to access the network or may be a device that is incorrectly connected. The characteristic current signal verification can ensure that the newly added node is a real low-voltage topology unit and not other devices that are incorrectly connected.

[0048] S402: If the changed node is a removed node, a heartbeat signal is sent to the removed node several times through the neighboring nodes of the removed node. If there is feedback, it is temporarily disconnected and the changed node is retained. Otherwise, the changed node is removed. In this step, the node may be temporarily disconnected due to power failure, overload, short-term loss, etc., but it is very likely to resume normal communication in the future. Therefore, for the temporarily disconnected node, keep its position in the topology and continue to monitor its status through heartbeat signals instead of immediately removing it from the topology. If there is no response to multiple heartbeat requests, it means that the node may have been physically disconnected or permanently removed, and it can be removed from the topology.

[0049] S403: If the changed node is a state-changed node, analyze the abnormal state type of the changed node, and update the topology structure according to the abnormal state type.

[0050] In this step, the state-changed node refers to an existing topological node whose state has changed (for example, communication quality has decreased, signal interference, hardware performance degradation, etc.), but the node itself is still in the network topology and has not been completely disconnected or added. In this case, by analyzing the reasons for the state change of the changed nodes one by one, it is determined whether to update the topology structure based on other state reasons. The specific steps for updating the topology structure based on the abnormal state type are the same as step S3.

[0051] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0052] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0053] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0054] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0055] It should be noted that in the claims, any reference signs placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claim. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.

[0056] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0057] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0058] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

Claims

1. A method for identifying substation topology based on low voltage topology unit, characterized in that: According to a substation topology identification system based on a low voltage topology unit, the system comprises: A plurality of low-voltage topology units are respectively deployed in nodes of the low-voltage line and are used to generate and collect characteristic current signals in the low-voltage line. The plurality of low-voltage topology units form a multi-level topology structure. The fusion topology unit is deployed at the distribution transformer of the low-voltage line to control the low-voltage topology unit and perform topology analysis and identification based on the characteristic current signals collected by the low-voltage topology unit. The method comprises: The fusion topology unit controls the low-voltage topology unit to send characteristic current signals in sequence, and the low-voltage topology unit receives and identifies the characteristic current signals in real time and then reports the identification and recording data; The fusion topology unit generates a first topology structure according to the identification record data of all low-voltage topology units, and regularly monitors the abnormal state of each low-voltage topology unit through the first topology structure; If the proportion of the number of low-voltage topology units in the abnormal state is lower than the first proportion threshold, analyzing the abnormal state type of the low-voltage topology unit, and updating the topology structure according to the abnormal state type; If the proportion of low-voltage topology units in abnormal state exceeds the first proportion threshold, global topology identification is performed to obtain a second topology structure, the second topology structure is compared with the first topology structure to obtain a changed node, and the topology structure is updated according to the changed node type.

2. A method for identifying substation topology based on a low voltage topology unit according to claim 1, characterized in that: The fusion topology unit controls the low-voltage topology unit to send characteristic current signals in sequence, and the low-voltage topology unit receives and identifies the characteristic current signals in real time and then reports the identification record data, including: The fusion topology unit sends control commands to each low-voltage topology unit in turn through broadband carrier communication; The low voltage topology unit generates a characteristic sequence code bit according to the control command to generate and send a characteristic current signal, and stores default information in any code bit; Each low-voltage topology unit samples and identifies the characteristic current signal in real time. If the identification is successful, the characteristic sequence information of the characteristic current signal and the physical location of the node are reported.

3. A method for identifying substation topology based on a low voltage topology unit according to claim 2, characterized in that: The real-time sampling and identification of characteristic current signals by each low-voltage topology unit includes: Each low-voltage topology unit samples characteristic current signals, and starts identification when more than N groups of characteristic current signals are present continuously; During identification, if there are more than N+1 groups with characteristic current signals, they are marked as 1 and matched with the default information. If the match is successful, the identification is successful.

4. The method for identifying substation topology based on low voltage topology unit according to claim 1, characterized in that: The fusion topology unit generates a first topology structure according to the identification record data of all low-voltage topology units, including: After all low-voltage topology units have executed control commands and reported identification record data, the fusion topology unit counts the number of identifications of each low-voltage topology unit; The fusion topology unit recursively sorts out the hierarchical topological structure of each route according to the number of recognition times from low to high, and forms a first topological structure by integrating the hierarchical topological structure of each route.

5. The method for identifying substation topology based on low voltage topology unit according to claim 1, characterized in that: The step of regularly monitoring the abnormal state of each low-voltage topology unit through the first topology structure includes: By each low-voltage topology unit periodically sending a heartbeat signal to an adjacent low-voltage topology unit according to the first topology structure; If a low-voltage topology unit does not receive the heartbeat signal sent by a neighboring low-voltage topology unit, it records that the state of the neighboring low-voltage topology unit is abnormal and broadcasts it to the fusion topology unit.

6. The method for identifying substation topology based on low voltage topology unit according to claim 1, characterized in that: If the proportion of low-voltage topology units in the abnormal state is lower than the first proportion threshold, analyzing the abnormal state type of the low-voltage topology unit, and updating the topology structure according to the abnormal state type includes: The fusion topology unit initiates several heartbeat signals to the low-voltage topology unit in the abnormal state, and records the response success rate R. If the response success rate R ≥ 60%, the abnormal state is classified as instantaneous interference, and the topology node corresponding to the low-voltage topology unit is retained; If 20%≤response success rate R<60%, the abnormal state is classified as an intermittent fault, and the topology node corresponding to the low-voltage topology unit is retained. If the response success rate R<20%, neighbor collaborative verification is performed.

7. A method for identifying substation topology based on low voltage topology unit according to claim 6, characterized in that: The steps of neighbor collaborative verification are as follows: Initiate several heartbeat signals to the low-voltage topology unit in the abnormal state through the adjacent low-voltage topology unit; The packet loss rate PLR ​​and delay L of the heartbeat signal of all adjacent low-voltage topology units are collected, and the communication quality index Q is calculated by the packet loss rate PLR ​​and delay L of the heartbeat signal. The calculation formula of the communication quality index Q is: ， in, is the packet loss rate of the heartbeat signal The weight of Delay L The weight of If the communication quality index Q>0.8, the abnormal state is classified as a communication failure, and the topology node corresponding to the low-voltage topology unit is removed, otherwise the characteristic current signal verification is performed.

8. A method for identifying substation topology based on low voltage topology unit according to claim 7, characterized in that: The steps of verifying the characteristic current signal are as follows: A special verification sequence is sent to the low-voltage topology unit in the abnormal state, requiring all low-voltage topology units in the branch where the low-voltage topology unit in the abnormal state is located to feedback the signal strength within the window period; Calculate signal attenuation by feedback signal strength , if the average signal attenuation >30dB, the abnormal state is classified as a physical line interruption, and the topology node corresponding to the low-voltage topology unit is removed.

9. A method for identifying substation topology based on low voltage topology unit according to claim 8, characterized in that: The average signal attenuation The calculation formula is as follows: ， ， in, is the attenuation of a single path, is the signal strength sent by the low-voltage topology unit end of the branch, is the signal strength received by the fusion topology unit, i represents the i-th signal branch, and M represents the number of signal branches.

10. The method for identifying substation topology based on low voltage topology unit according to claim 1, characterized in that: If the proportion of the number of low-voltage topology units in the abnormal state exceeds the first proportion threshold, global topology identification is performed to obtain a second topology structure, the second topology structure is compared with the first topology structure to obtain a changed node, and the topology structure is updated according to the type of the changed node, including: If the changed node is a newly added node, the characteristic current signal of the newly added node is verified, and after the verification is passed, it is updated to the topology structure; If the changed node is a removed node, a number of heartbeat signals are sent to the removed node through the neighboring nodes of the removed node. If there is feedback, it is temporarily disconnected and the changed node is retained. Otherwise, the changed node is removed. If the changed node is a state-changed node, the abnormal state type of the changed node is analyzed, and the topology structure is updated according to the abnormal state type.

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