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

Abstract

The present invention discloses a method for identifying the topology of a low-voltage area based on a low-voltage topology unit, including: the fusion topology unit controls the low-voltage topology unit to sequentially send characteristic current signals, and the low-voltage topology unit receives and identifies the characteristic current signals in real time and then reports the 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 states 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, analyze the type of the abnormal state of the low-voltage topology unit, and update the topology structure according to the type of the abnormal state; if the proportion of the number of low-voltage topology units in the abnormal state exceeds the first proportion threshold, perform global topology identification to obtain a second topology structure, compare the second topology structure with the first topology structure to obtain the changed nodes, and update the topology structure according to the type of the changed nodes.

Description

Technical Field

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

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

[0003] The topological information of traditional low-voltage lines in a substation area 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 relationships. With line renovations or changes in user access, the topological information cannot be dynamically updated. Existing substation area topology identification deploys low-voltage topology units at key nodes of the low-voltage lines in the substation area, and can identify the connection relationships between nodes in real time by receiving and transmitting characteristic current signals, and draw the actual topological structure.

[0004] However, the topological structure of actual low-voltage lines often changes (such as new users, line renovations, equipment replacements, etc.). When the low-voltage topology unit detects a topological change, it often needs to re-perform global topology identification. Since the existing technology relies on the fixed transmission and reception of static characteristic current signals and does not perform dynamic update judgment based on the actual change reasons, the identification efficiency is reduced.

[0005] During the topological update identification process, inaccurate topology identification may occur due to some local interferences (such as signal noise, instantaneous electromagnetic interference) or intermittent faults (such as short-term disconnection of nodes, weak signals). The existing technology usually directly adopts the method of re-performing global topology identification, fails to make full use of the existing topological 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 new nodes, removed nodes, nodes with state changes), resulting in insufficient accuracy and efficiency of topological update identification.

[0006] Designing a substation area topology identification method based on low-voltage topology units to address the above existing problems in the prior art is the objective of the research of the present invention. Summary of the Invention

[0007] In view of this, the objective of the present invention is to propose a substation area topology identification method based on low-voltage topology units, which can solve the above problems.

[0008] The present invention provides a substation area topology identification method based on low-voltage topology units, according to a substation area topology identification system based on low-voltage topology units, including:

[0009] A number of low-voltage topology units are respectively deployed at the nodes of the low-voltage line, and are used to generate and collect characteristic current signals in the low-voltage line. The number of low-voltage topology units forms a multi-level topology structure;

[0010] A fusion topology unit is deployed at the distribution transformer of the low-voltage line and is used to control the low-voltage topology units and perform topology analysis and identification according to the characteristic current signals collected by the low-voltage topology units;

[0011] The method includes:

[0012] The fusion topology unit controls the low-voltage topology units to sequentially send characteristic current signals. After the low-voltage topology units receive and identify the characteristic current signals in real time, they report the identification record data;

[0013] 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;

[0014] If the proportion of the number of low-voltage topology units in the abnormal state is lower than the first proportion threshold, analyze the type of abnormal state of the low-voltage topology unit, and update the topology structure according to the type of abnormal state;

[0015] If the proportion of the number of low-voltage topology units in the abnormal state exceeds the first proportion threshold, perform global topology identification to obtain a second topology structure, compare the second topology structure with the first topology structure to obtain the changed nodes, and update the topology structure according to the type of changed nodes.

[0016] Furthermore, the fusion topology unit controls the low-voltage topology units to sequentially send characteristic current signals. After the low-voltage topology units receive and identify the characteristic current signals in real time, they report the identification record data, including:

[0017] The fusion topology unit sequentially issues control commands to each low-voltage topology unit through broadband carrier communication;

[0018] 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 at any code bit;

[0019] 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.

[0020] Furthermore, each low-voltage topology unit samples and identifies the characteristic current signal in real time, including:

[0021] Each low-voltage topology unit samples the characteristic current signal. When there are characteristic current signals for more than N consecutive groups, the identification is started;

[0022] During recognition, if there are more than N + 1 groups of characteristic current signals, it is marked as 1, and code bit matching is performed with the default information. If the matching is successful, the recognition is successful.

[0023] Furthermore, the first topology structure generated by the fusion topology unit based on the recognition record data of all low-voltage topology units includes:

[0024] After all low-voltage topology units have executed the control commands and reported the recognition record data, the fusion topology unit counts the recognition times of each low-voltage topology unit;

[0025] The fusion topology unit recursively sorts out the hierarchical topology structure of each route from low to high according to the recognition times, and synthesizes the hierarchical topology structures of each route to form the first topology structure.

[0026] Furthermore, the abnormal state of each low-voltage topology unit is regularly monitored through the first topology structure, including:

[0027] Each low-voltage topology unit regularly sends a heartbeat signal to adjacent low-voltage topology units according to the first topology structure;

[0028] If a certain low-voltage topology unit does not receive the heartbeat signal sent by its neighbor low-voltage topology unit, record the abnormal state of this neighbor low-voltage topology unit and broadcast it to the fusion topology unit.

[0029] Furthermore, if the number of low-voltage topology units in the abnormal state is lower than the first proportion threshold, analyze the type of abnormal state of the low-voltage topology unit, and update the topology structure according to the type of abnormal state, including:

[0030] The fusion topology unit sends 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%, this abnormal state is classified as transient interference, and the topology node corresponding to this low-voltage topology unit is retained;

[0031] If 20% ≤ response success rate R < 60%, this abnormal state is classified as intermittent fault, and the topology node corresponding to this low-voltage topology unit is retained. If the response success rate R < 20%, neighbor collaborative verification is performed.

[0032] Furthermore, the steps of the neighbor collaborative verification are as follows:

[0033] Adjacent low-voltage topology units send several heartbeat signals to the low-voltage topology unit in the abnormal state;

[0034] Collect the packet loss rate PLR and delay L of the heartbeat signals of all adjacent low-voltage topology units, and calculate the communication quality index Q through the packet loss rate PLR and delay L of the heartbeat signals. The calculation formula of the communication quality index Q is:

[0035] ,

[0036] Among them, is the packet loss rate of the heartbeat signal weight, is the time delay L weight;

[0037] If the communication quality index Q > 0.8, then 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 is verified.

[0038] Furthermore, the steps of the characteristic current signal verification are as follows:

[0039] Send a special verification sequence to the low-voltage topology unit in the abnormal state, and require all low-voltage topology units on the branch where the low-voltage topology unit in the abnormal state is located to feedback the signal strength within the window period;

[0040] Calculate the signal attenuation degree through the feedback signal strength , if the average signal attenuation degree > 30 dB, then the abnormal state is classified as a physical line interruption, and the topology node corresponding to the low-voltage topology unit is removed.

[0041] Furthermore, the calculation formula of the average signal attenuation degree is as follows:

[0042] , ,

[0043] Among them, is the attenuation degree of a single path, is the signal strength sent by the low-voltage topology unit at the end of the branch where it is located, 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] Furthermore, if the proportion of the number of low-voltage topology units in the abnormal state exceeds the first proportion threshold, then global topology recognition is performed to obtain a second topology structure, the second topology structure is compared with the first topology structure to obtain changed nodes, and the topology structure is updated according to the changed node type, including:

[0045] If the changed node is a newly added node, perform characteristic current signal verification on the newly added node, and update it to the topology structure after passing the verification;

[0046] If the changed node is a removed node, send several heartbeat signals from the neighbor nodes of the removed node to the removed node. If there is feedback, it is a temporary disconnection, and the changed node is retained; otherwise, the changed node is removed;

[0047] If the changing node is a status-changing node, analyze the type of abnormal status of the changing node and update the topological structure according to the type of abnormal status.

[0048] Advantages of the present invention:

[0049] First, by sending and receiving characteristic current signals, the physical connection relationship between low-voltage topological units can be clearly identified. The characteristic current signals can promptly capture changes such as newly added nodes and wiring modifications, and accurately reflect the actual connection of the network.

[0050] Second, by fusing the topological unit summary and analyzing the identification data of low-voltage topological units, an overall network model (i.e., the first topological structure) of the substation area can be generated to ensure topological accuracy. Relying on the logical relationship of the first topological structure during the monitoring process, abnormal nodes can be quickly discovered and locked, ensuring the stability of network operation.

[0051] Third, by judging the proportion of low-voltage topological units in the abnormal state, for local abnormal problems, topological updates are performed in a classified processing manner (such as instantaneous interference, intermittent faults, communication problems, etc.), without triggering global topological re-identification, reducing the system calculation and communication burden. Combining the type of abnormal status (such as instantaneous interference processing, neighbor collaborative verification, characteristic current signal verification, etc.), the topological structure can be quickly updated to ensure the high-efficiency response of the system.

[0052] Fourth, when the proportion of nodes in the abnormal state is relatively high (such as when exceeding the threshold, it may involve problems of multiple regional devices or main lines), by performing global topological identification, the latest second topological structure is obtained and completely replaces the original structure. The comparison between the first topology and the second topology can accurately locate the changing nodes, clarify the scope of topological changes, and then update the topology according to the type of changing nodes. Description of the Drawings

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0054] Figure 1 is the method flowchart of Embodiment 2.

[0055] Figure 2 is the identification record structure diagram of Embodiment 2.

[0056] Figure 3 is the first topological structure diagram of Embodiment 2. Detailed Embodiments

[0057] For the convenience of those skilled in the art to understand, the structure of the present invention will be further described in detail with reference to the accompanying drawings in the embodiments. It should be understood that the steps mentioned in this embodiment, unless specifically stating their order, can be adjusted according to actual needs in terms of their front and back order, and can even be executed simultaneously or partially simultaneously.

[0058] Embodiment 1

[0059] Embodiment 1 provides a substation area topology recognition system based on low-voltage topology units, including:

[0060] A number of low-voltage topology units are respectively deployed at the nodes of the low-voltage line, used to generate and collect characteristic current signals in the low-voltage line. A number of low-voltage topology units form a multi-level topology structure;

[0061] The fusion topology unit is deployed at the distribution transformer of the low-voltage line, used to control the low-voltage topology units and perform topology analysis and recognition according to the characteristic current signals collected by the low-voltage topology units;

[0062] In this embodiment, low-voltage topology units LTU (Low-voltage Topology Unit) that support live construction are installed in the three-level low-voltage lines of the substation area (low-voltage feeder switch, branch box outgoing switch, meter box incoming switch). After the installation of the low-voltage topology unit LTU is completed, it is automatically registered in the broadband carrier communication network and actively reported to the fusion topology unit TTU (Terminal Topology Unit).

[0063] The internal circuit of the low-voltage topology unit is designed with a characteristic current generation module. The generation module is a constant resistance load and can be used to generate characteristic current signals. The internal circuit of the low-voltage topology unit is designed with a characteristic current receiving module, and the receiving module samples the characteristic current signals in the sending frequency band in real time.

[0064] Embodiment 2

[0065] As Figure 1 shown, Embodiment 2 provides a method for recognizing the substation area topology based on low-voltage topology units, including:

[0066] S1 The fusion topology unit controls the low-voltage topology units to sequentially send characteristic current signals. After the low-voltage topology units receive and identify the characteristic current signals in real time, they report the identification record data;

[0067] S101 The fusion topology unit sequentially issues control commands to each low-voltage topology unit through broadband carrier communication;

[0068] S102 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;

[0069] Furthermore, before this step you need to execute:

[0070] If other communication frequency bands exist on the current low-voltage line, the low-voltage topology unit sends a characteristic current signal at the second frequency according to the control command.

[0071] 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.

[0072] 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].

[0073] 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.

[0074] 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.

[0075] 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;

[0076] 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.

[0077] In this step, taking 60 ms as a group, if there is a characteristic current signal marked as 1 and it continuously exceeds 6 groups, then the recognition is enabled. During recognition, 10 consecutive groups form 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 identifying the characteristic information, it is bitwise matched with the default information [0xAAE9, 0xD577, 0xCC95, 0xB36B]. If the matching of the code bits is successful, the recognition is successful. The mark "1" is a preliminary detection of the characteristic current signal, used to judge the existence of the signal; while the matching of the code bits is to further verify the accuracy and uniqueness of the signal, ensuring that the signal comes from the target low-voltage topology unit. The process of matching the code bits can effectively filter out interference signals and improve the reliability and accuracy of recognition.

[0078] The S2 fusion topology unit generates the first topology structure based on the recognition record data of all low-voltage topology units, and regularly monitors the abnormal status of each low-voltage topology unit through the first topology structure;

[0079] S201 When all low-voltage topology units have completed the control commands and reported the recognition record data, the fusion topology unit counts the recognition times of each low-voltage topology unit;

[0080] S202 The fusion topology unit recursively sorts out the hierarchical topology structure of each route from low to high according to the recognition times, and synthesizes the hierarchical topology structures of each route to form the first topology structure.

[0081] In this step, as Figure 2 、 Figure 3 shown, only when all low-voltage topology units (LTU1~LTU17) have completed the characteristic current sending and recognition tasks can it be ensured that all nodes in the substation area are included in the topological relationship. If there is a low-voltage topology unit that fails to execute the command or report the recognition record, it may lead to omissions in the topological relationship and unable to reflect the complete physical structure of the substation area. The fusion topology unit TTU will count the recognition times of each low-voltage topology unit. The recognition times reflect the propagation level of the characteristic current signal in the topology structure: the recognition times of the upper-level nodes are higher because they are located upstream of the signal propagation path, and the recognition times of the lower-level nodes are lower because they are 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.

[0082] S203 Each low-voltage topology unit regularly sends a heartbeat signal to adjacent low-voltage topology units according to the first topology structure;

[0083] S204 If a certain low-voltage topology unit does not receive the heartbeat signal sent by its neighbor low-voltage topology unit, it records the abnormality of this neighbor low-voltage topology unit and broadcasts and reports it to the fusion topology unit;

[0084] 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.

[0085] 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;

[0086] 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.

[0087] 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;

[0088] 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.

[0089] If 20% ≤ response success rate R < 60%, then this abnormal state is classified as an intermittent fault, and the topology node corresponding to this low-voltage topology unit is retained. If the response success rate R < 20%, then neighbor collaborative verification is performed;

[0090] In this step, the response success rate of the low-voltage topology unit is low but not zero, indicating that there may be hardware problems or minor communication interference in the low-voltage topology unit, resulting in its unstable state. The low-voltage topology unit remains in the topology, but its state is marked as "intermittent fault". The fusion topology unit can include this low-voltage topology unit in the maintenance plan and issue a maintenance task. If these nodes are removed without distinguishing the reasons, it is easy to make misjudgments 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.

[0091] Neighbor collaborative verification, specifically:

[0092] Initiate several heartbeat signals from adjacent low-voltage topology units to the low-voltage topology unit in the abnormal state;

[0093] Collect the packet loss rate PLR and delay L of all heartbeat signals of adjacent low-voltage topology units, and calculate the communication quality index Q through the packet loss rate PLR and delay L of the heartbeat signals. The calculation formula of the communication quality index Q is:

[0094] ,

[0095] Among them, is the packet loss rate of the heartbeat signal the weight of is the delay L the weight of;

[0096] If the communication quality index Q > 0.8, then this abnormal state is classified as a communication fault, and the topology node corresponding to this low-voltage topology unit is removed. Otherwise, characteristic current signal verification is performed;

[0097] In this step, the adjacent low-voltage topology units can be low-voltage topology units within 3 hops. The response success rate is extremely low, and neighbor collaborative verification shows that the surrounding communication quality is poor, indicating that the problem may be caused by a communication fault. Temporarily remove the connection relationship of this node from the topology, but retain its physical location information. The fusion topology unit can include this node in the maintenance plan and issue a maintenance task. The introduction of the communication quality index provides a quantitative classification standard based on packet loss rate and delay for abnormal nodes, which can effectively distinguish faults caused by communication interference (such as signal attenuation, noise interference) from hardware-level or line-level faults (such as open circuits or device damage).

[0098] Characteristic current signal verification, specifically:

[0099] Send a special verification sequence to the low-voltage topology unit in an abnormal state, and require all low-voltage topology units on the branch where the low-voltage topology unit in the abnormal state is located to feedback the signal strength within the window period;

[0100] Calculate the signal attenuation degree through the feedback signal strength , if the average signal attenuation degree > 30 dB, then classify this abnormal state as a physical interruption of the line and remove the topology node corresponding to this low-voltage topology unit;

[0101] Specifically, the calculation formula of the average signal attenuation degree is as follows:

[0102] , ,

[0103] where, is the attenuation degree of a single path, is the signal strength sent by the low-voltage topology unit end of the branch where it is located, 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.

[0104] In this step, the verification of the characteristic current signal shows that the signal attenuation degree of the node is too high, indicating that there may be a physical disconnection or a serious impedance problem in the line. Mark the state of the topology node corresponding to this low-voltage topology unit as "physical interruption of the line" in the topology. A physical interruption of the line (such as a break) is an abnormality that has a significant impact on the network topology. Remove this node and its corresponding branch from the topology structure to avoid affecting the communication of other nodes. The fusion topology unit can include this node in the maintenance plan and issue a maintenance task.

[0105] S4 If the proportion of the number of low-voltage topology units in the abnormal state exceeds the first proportion threshold, perform global topology identification to obtain a second topology structure, compare the second topology structure with the first topology structure to obtain the changed nodes, and update the topology structure according to the type of the changed nodes.

[0106] In this step, when the proportion of low-voltage topology units in the 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 a regional communication failure or a disconnection of the main line, which may involve state changes caused by the addition or removal of multiple nodes (such as structural changes caused by the access of new devices, or the overall failure of the branch). At this time, it is necessary to comprehensively re-analyze the system through global topology identification to obtain an accurate second topology structure, and it is necessary to perform comparison and verification according to the first topology structure to ensure the accuracy of the update of the changed nodes, and at the same time perform topology update according to the specific structure type of the changed nodes.

[0107] If the changed node is a newly added node, verify the characteristic current signal of the newly added node. After passing the verification, update it to the topological structure;

[0108] In this step, the newly added node may be a device that unauthorizedly accesses the network or may be a wrong access of a device. The verification of the characteristic current signal can ensure that the newly added node is a real low-voltage topological unit and ensure that it is not other devices with wrong access.

[0109] If the changed node is a removed node, send several heartbeat signals to the removed node through the neighbor nodes of the removed node. If there is feedback, it is a temporary disconnection, and keep this changed node; otherwise, remove this changed node;

[0110] In this step, the node may be temporarily interrupted due to reasons such as power failure, overload, and short-term loss, but it is very likely to resume normal communication in the future. Therefore, for a temporarily disconnected node, keep its position in the topology and continue to monitor its status through heartbeat signals, rather than immediately removing it from the topology. If there is no response to multiple heartbeat requests, it indicates that the node may have been physically disconnected or permanently removed, and at this time, it can be removed from the topology.

[0111] If the changed node is a node with a status change, analyze the type of abnormal status of the changed node, and update the topological structure according to the type of abnormal status.

[0112] In this step, the node with a status change refers to an existing topological node whose status has changed (such as a decrease in communication quality, signal interference, attenuation of hardware performance, etc.), but the node itself is still in the network topology and has not been completely disconnected or newly added. In this case, by analyzing the reasons for the status change of each changed node one by one, determine whether to update the topological structure according to other status reasons. The specific steps for updating the topological structure according to the type of abnormal status are the same as step S3.

[0113] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can adopt the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can adopt 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.) that contain computer-usable program code.

[0114] The present invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each flow and / or block in the flowchart illustrations and / or block diagrams, and combinations of flows and / or blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing apparatus create means for implementing the functions specified in the flowchart flow or flows and / or block or blocks. Figure 1 in one or more of the flows and / or blocks Figure 1 or boxes.

[0115] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means that implement the functions specified in the flowchart flow or flows and / or block or blocks. Figure 1 in one or more of the flows and / or blocks Figure 1 or boxes.

[0116] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and / or block or blocks. Figure 1 in one or more of the flows and / or blocks Figure 1 or boxes.

[0117] It should be noted that, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims listing several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, and third, etc. do not denote any order. These words may be interpreted as names.

[0118] Although the preferred embodiments of the invention have been described, additional changes and modifications can be made by those skilled in the art once they learn of the basic inventive concept. Therefore, the appended claims are intended to be construed to cover the preferred embodiments as well as all changes and modifications that fall within the scope of the invention.

[0119] Obviously, those skilled in the art can make various modifications and variations 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 equivalent technologies, the present invention is also intended to include these modifications and variations.

[0120] In the present invention, unless otherwise clearly specified and defined, the terms "mounted", "connected", "connected to", "fixed", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0121] 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 connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions 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 can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

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, the abnormal state type of the low-voltage topology unit is analyzed, and the topology structure is updated according to the abnormal state type. Specifically: 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. 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; If the proportion of low-voltage topology units in abnormal state exceeds the first proportion threshold, global topology recognition is performed to obtain a second topology structure, and the second topology structure is compared with the first topology structure to obtain a changed node. The topology structure is updated according to the type of the changed node. Specifically: 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.

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 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: Periodically sending a heartbeat signal to an adjacent low-voltage topology unit by each 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: The steps of verifying the characteristic current signal are as follows: Send a verification sequence 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.

7. A method for identifying substation topology based on low voltage topology unit according to claim 6, 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.

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