Low-voltage power distribution network phase line topology identification method and system

Abstract

The invention discloses a low-voltage power distribution network phase line topology identification method and system, and mainly relates to the technical field of low-voltage power distribution network phase line topology identification. Comprising the following steps: analyzing a phase line relation based on a graph theory model, and determining a known area and an unknown area of a transformer area according to the installation and operation conditions of LTU and whether the line topology is known or not; according to an identification result, performing phase line relation configuration on the known region; based on the analysis result, identifying the overall phase line topological relation in the transformer area; and performing phase line relation configuration on the unknown region according to the recognition result of the unknown region. The method has the advantages that the topological relation in the distribution room and the distribution board of an actual transformer area is fully utilized, area division is achieved, phase line relation configuration is carried out on a known area, the processing amount of data of an unknown area is reduced, and meanwhile the topological recognition accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of low-voltage distribution network line topology identification, and in particular to a low-voltage distribution network phase line topology identification method and system based on IEC_61850SCL and K-means. Background Art

[0002] Low-voltage distribution network line topologies often employ a combination of radial, trunk, and ring wiring, with low-voltage phase lines employing three-phase four-wire or single-phase two-wire systems. Current research often uses correlation analysis between transformer node data and end-user data to obtain phase relationship information for end users. Some end users are located at long electrical distances from transformer nodes, resulting in low correlation in electrical data. To address voltage imbalances, low-voltage distribution networks employ phase-changing switches for load transfer, resulting in dynamic changes in the phase relationship for some users. Furthermore, some older residential communities lack phase line configuration and timely update of these relationships, resulting in incomplete phase relationship in some areas. To ensure the safe and stable operation of low-voltage distribution substations, LTUs are installed in distribution rooms, pole-mounted transformers, and other locations to monitor and protect low-voltage feeder lines. LTUs support automatic electrical topology identification, so the topology of the lines within their monitoring range is known. Analysis reveals that the topology of incoming and outgoing lines within the distribution panel is also known. However, due to cost and environmental constraints, LTUs do not fully monitor the entire substation. At the same time, due to the lack of effective configuration of phase-line relationships, information updates are not timely, and the phase-line relationships of users in some areas are unknown or change dynamically.

[0003] Although some researchers have adopted traditional methods such as manual line inspection, signal injection, and data analysis to identify the phase line topology of low-voltage lines, the following problems still exist:

[0004] Low-voltage distribution networks have diverse wiring methods and a wide distribution range. Line inspections section by section consume a lot of manpower and are inefficient.

[0005] The signal injection method can identify the phase line relationship by detecting the characteristic signal sent by the high-speed power line broadband carrier (HPLC). The HPLC method has strong real-time performance, strong anti-interference ability, and can achieve chip-level interconnection and interoperability, which is more suitable for the current data acquisition and communication needs. However, due to the stage construction of the power grid, some areas have not adopted the HPLC communication method. At the same time, the low-voltage distribution line structure is complex, and it is difficult to meet the application requirements with a single communication method, so it needs to be combined with other methods.

[0006] Currently, most data analysis methods use correlation analysis between user data and transformer data, and most of them analyze all the data in the entire substation area. They often combine algorithms and process all the user-transformer data in the substation area at the same time. The computational complexity is large and it may be difficult to implement on resource-constrained terminal devices.

[0007] K-means clustering is widely used in distribution networks to identify transformer-to-user topologies due to its simplicity, fast convergence speed, and high efficiency. However, the K-means clustering algorithm is easily affected by the initial cluster center and the number of clusters, resulting in a low recognition rate. Therefore, the use of a single recognition method has not effectively solved the problem of low-voltage topology line identification.

[0008] Current research mainly focuses on the identification of static phase lines, without considering the dynamic changes of phase lines caused by phase-changing switches.

[0009] Therefore, a low-voltage distribution network phase line topology identification method and system based on IEC 61850SCL and K-means is urgently needed to solve the above problems. Summary of the Invention

[0010] The purpose of the present invention is to provide a low-voltage distribution network phase line topology identification method and system based on IEC 61850 SCL and K-means to solve the above problems. It fully utilizes the topological relationship in the distribution room and distribution board of the actual substation to improve the accuracy of topology identification.

[0011] To achieve the above-mentioned purpose, the present invention is implemented through the following technical solutions:

[0012] On the one hand, a method for identifying a phase line topology of a low-voltage distribution network is provided, characterized in that the method comprises the following steps:

[0013] S1: Analyze the phase-line relationship based on a graph theory model and determine the known and unknown areas of the substation based on the installation and operation status of the LTU and whether the line topology is known;

[0014] S2: Based on the identification result of step S1, configure the phase line relationship of the known area in step S1. Based on the analysis result of step S1, identify the entire phase line in the substation area;

[0015] S3: Based on the analysis results in step S1, the overall phase line topology relationship in the substation area is identified. According to the identification results in step S3, the phase line relationship is configured for the known area in step S1;

[0016] S4: According to the recognition result of step S3, the unknown area in step S1 is configured with a phase line relationship based on step S2.

[0017] Preferably, the step S1 includes:

[0018] The low-voltage distribution network lines are abstracted as a collection of low-voltage distribution network edges and nodes. The relationship between topological blocks is reflected through the connection relationship between nodes and edges, and between nodes in the network structure diagram. Based on graph theory, the low-voltage distribution network phase line relationship topology is modeled as a four-tuple. The physical model of nodes, edges, and switch states is converted into a mathematical model of transformers, edges, and switches.

[0019] Based on the graph theory model, the known and unknown areas of the substation are determined according to the installation and operation status of the LTU and whether the line topology is known.

[0020] Preferably,

[0021] Based on graph theory, the four-tuple of low-voltage distribution network line topology is established = (V, E, S, X). The set of nodes, edges, switches, and commutation switches of the low-voltage distribution network line are represented as V G ={v1, v2, ..., v n}、E G ={e1, e2, ..., e m}、S k ∈[0,1],X i ∈[0, 1], where e k ∈[1,3], when the value is 1, it indicates a single-phase line, when the value is 3, it indicates a three-phase line, S k =0, indicating the switch is off, S k =1, indicating that the switch is closed. If commutation occurs, then X i It changes to 1 and performs topology update. After the update, it changes to 0 and performs the corresponding action after the next phase change.

[0022] Map the phase line topology of the substation area into the network structure diagram G, E total →G total , where e∈E total , g∈G total , map(e)=g means that any low-voltage phase line relationship topology diagram can be represented by a network structure diagram;

[0023] The transformer node is taken as the root node, the terminal load or DER is taken as the leaf node, and the node where the line intersects is taken as the branch node. If the area is monitored by n LTUs, the known and unknown areas of the substation are determined based on the installation and operation status of the LTUs and whether the line topology is known. The low-voltage line is divided into n small areas according to the monitoring range of the LTUs, and the graph G is divided into n subgraphs.

[0024] Preferably, the step 2 comprises the following steps:

[0025] S21: Introduce the Line container of the low-voltage distribution network into the low-voltage area to describe the lines between substations;

[0026] S22: The segmented lines between the devices in the low-voltage distribution station use the Line container of the low-voltage distribution network, and the upper layer uses a Process container to represent the entire substation;

[0027] S23: The switches of the line are described using Substation containers;

[0028] S24: Add the phases attribute to increase the configuration of the phase line of the substation line topology;

[0029] S25: Steps S21-S24 build a hierarchical model of the low-voltage distribution network topology based on IEC 61850SCL, configure lines according to the divided areas, and represent an area using a Substation container.

[0030] Preferably, the step S3 includes the following steps:

[0031] S31: If there are users in the substation area with known phase-line relationships, the phase-line relationships are configured based on IEC 61850 SCL, and the substation area line topology is divided into unknown areas according to step S1;

[0032] S32: For areas where LTU equipment is installed and the LTU is operating normally, if the substation is configured with HPLC communication, the phase line relationship based on HPLC communication is used for identification;

[0033] S33: For areas where HPLC is not configured, user meter voltage correlation analysis is performed based on the k-means algorithm to identify user phase and line relationships;

[0034] S34: After the phase-line relationship of users in the unknown area is identified, the phase-line relationship is configured based on IEC 61850 SCL.

[0035] Preferably, step S4 is specifically as follows: for unknown areas configured with HPLC, the phase line relationship can be identified based on HPLC; for unknown areas not configured with HPLC, the phase line is identified after correlation analysis between voltage measurement values ​​is performed based on k-means clustering.

[0036] Preferably, the k-means clustering includes:

[0037] Set the initial number of clusters;

[0038] Select the initial centroid;

[0039] Voltage correlations were calculated according to the Pearson correlation coefficient method.

[0040] Preferably,

[0041] Select the user voltage data of the actual low-voltage distribution area, set the unknown area, and determine the actual topology line of the distribution area;

[0042] When a user sampling point fails, the value at time t-1 is used to fill in the voltage and data.

[0043] By analyzing the voltage data samples, the voltage data over a period of time is statistically analyzed and k-means cluster analysis is performed to determine the topological relationship.

[0044] On the other hand, a system for identifying a low-voltage distribution network phase line topology based on the above-mentioned method is provided, comprising:

[0045] The area determination module is used to analyze the phase-line relationship based on a graph theory model and determine the known and unknown areas of the substation area based on the installation and operation status of the LTU and whether the line topology is known;

[0046] Phase line identification module, used to: identify the entire phase line in the substation based on the analysis results;

[0047] The phase line relationship configuration module is used to: configure the phase line relationship of the known area according to the recognition results; and configure the phase line relationship of the unknown area according to the phase line relationship recognition results.

[0048] Compared with the prior art, the beneficial effects of the present invention are:

[0049] 1. Because the medium-voltage distribution network adopts a configuration solution based on IEC 61850, while the low-voltage distribution network adopts a topology configuration based on IEC61850 SCL, it is easier to achieve medium- and low-voltage data integration.

[0050] 2. Two phase line configuration schemes are proposed: Terminal extension and new phase line description logical nodes (PPLDs). The configuration method can be selected based on the actual needs of the low-voltage distribution network substation. This helps solve the problem of dynamic changes in phase line relationships caused by phase switching and enables dynamic updates of phase line relationships.

[0051] 3. Integrating the regionalization strategy, a k-means algorithm is used to analyze the correlation between voltage measurements of user voltage data in unknown areas. This method avoids the influence of the number of clusters and the initial cluster centers in k-means clustering, improving the accuracy of phase line identification. Cluster analysis is performed only on user voltage data in unknown areas, avoiding resource waste. Compared with identification solutions that use a combination of algorithms, this method is more suitable for resource-constrained end devices.

[0052] 4. The entire solution does not require additional equipment and is low-cost. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 is a method flow chart of the present application;

[0054] Figure 2 is a network structure diagram of the present application;

[0055] Figure 3 is a campus Substation and Line division diagram of the present application;

[0056] Figure 4 is a campus distribution room topology model diagram of the present application;

[0057] Figure 5 is a specific configuration example diagram of the interval and phase line of the present application;

[0058] Figure 6 is a phase line identification strategy flow chart of the present application;

[0059] Figure 7 is a low-voltage line HPLC communication diagram of the present application;

[0060] Figure 8 is a phase line identification process diagram of the present application;

[0061] Figure 9 is a phase line identification result schematic diagram of the present application;

[0062] Figure 10 is a system structure schematic diagram of the present application. DETAILED DESCRIPTION

[0063] The present application will be further described below in connection with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not used to limit the scope of the present application. Furthermore, it should be understood that after reading the content taught by the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the present application.

[0064] In the present application, the terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only a relationship word determined for the convenience of describing the structural relationship of the components or elements of the present application, and cannot be understood as a limitation on the present application.

[0065] In the present invention, terms such as "fixed connection," "connected," and "connection" should be interpreted broadly to mean a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediary. Relevant researchers or technicians in this field may determine the specific meanings of these terms in the present invention based on specific circumstances, and they should not be construed as limitations of the present invention.

[0066] Example:

[0067] like Figure 1 As shown, this embodiment provides a method for identifying a phase line topology of a low-voltage distribution network, comprising the following steps:

[0068] S1: Analyze the phase-line relationship based on a graph theory model and determine the known and unknown areas of the substation based on the installation and operation status of the LTU and whether the line topology is known;

[0069] S2: Based on the identification result of step S1, configure the phase line relationship of the known area in step S1. Based on the analysis result of step S1, identify the entire phase line in the substation area;

[0070] S3: Based on the analysis results in step S1, the overall phase line topology relationship in the substation area is identified. According to the identification results in step S3, the phase line relationship is configured for the known area in step S1;

[0071] S4: Based on the recognition result of step S3, the unknown area in step S1 is configured with phase line relationship based on step S2

[0072] S1: Phase line relationship analysis based on graph theory

[0073] Based on graph theory, the four-tuple of low-voltage distribution network line topology is established = (V, E, S, X). The set of nodes, edges, switches, and commutation switches of the low-voltage distribution network line are represented as V G ={v1, v2, ..., v n}、E G ={e1, e2, ..., e m}、S k ∈[0,1],X i ∈[0, 1], where e k ∈[1,3], when the value is 1, it indicates a single-phase line, when the value is 3, it indicates a three-phase line, S k =0, indicating the switch is off, S k =1, indicating that the switch is closed. If commutation occurs, then X i It changes to 1 and performs topology update. After the update, it changes to 0 and performs corresponding actions after the next phase change.

[0074] Map the phase line topology of the substation area into the network structure diagram G, Etotal →G total , where e∈E total , g∈G total , map(e)=g means that any low-voltage phase line relationship topology can be represented by a network structure diagram, such as Figure 2 shown.

[0075] Based on the modeling in Section 1, we construct an undirected graph G, with transformer nodes as root nodes, terminal loads or DERs as leaf nodes, and line intersection nodes as branch nodes. Assuming that the area is monitored by n LTUs, the low-voltage line is divided into n small areas based on the LTU monitoring range, and the graph G is divided into n subgraphs.

[0076] S2: Phase line relationship configuration method

[0077] Refer to the topology model and configuration method of IEC 61850-6Ed2.1 version, introduce the Line (line of low-voltage distribution network) container into the low-voltage area to describe the line between substations. It can contain the phase line, common equipment and connection nodes of the line. Figure 3 The dashed area shown is configured as a Substation. The segmented line between two Substations (equipment within a low-voltage distribution station, such as a distribution room, etc.) uses a Line container. The upper layer uses a Process (a local network of the low-voltage distribution network) container to represent the entire substation area. The line names in the Line container follow the unified naming rules of the State Grid. Because the Line container cannot describe switches, all line switches are described using the Substation container. The topology model based on SCL is as follows Figure 4 As shown. By extending the Terminal (an electrical connection point for a primary device) in the Line container and adding the phases attribute, you can configure the phase lines of the substation line topology. The phases attribute represents the phase lines of the substation. The phases attribute type is represented by type = tPhaseEnum. tPhaseEnum is assigned values ​​of A, B, C, and all. If the substation line phase line is not assigned a value, the default value is all.

[0078] But it can not achieve the description of the phase change switch. Therefore, based on the above line topology, the hierarchy of Substation, Bay, Conducting Equipment can be configured, and the line configuration is carried out according to the divided area, and one area is represented by the Substation container. Through the method of adding logical nodes to the primary topology specified in IEC 61850 SCL, the associated logical function is realized. Based on the DataTypeTemplates in the IEC 61850 SCL file, the data model of the related logical nodes contained in the LTU is described. Therefore, for the phase line of the transformer area, the description of the line phase line can be realized by creating a new logical node under the DataTypeTemplates element. Based on the logical node modeling rules of IEC 61850, a new phase line logical node PPLD (Phase line description) is created. As shown in Table 1, the configuration of the transformer area phase line is realized through the attributes of the PPLD logical node.

[0079] Table 1 Phase line description logical node PPLD

[0080]

[0081] Based on the hierarchical model of the low-voltage distribution network topology built by IEC 61850 SCL, in order to ensure the uniqueness of the configuration reference, the reference path is a hierarchical structure formed by the concatenation of the position names from top to bottom. According to the division of each area, the configuration of the regional topology of each area is carried out. Because there may be only one switch or one distribution room in the area, different configuration methods need to be selected according to different configuration requirements. The specific configuration example of E1Q1 is shown in Figure 5 .

[0082] S3: Overall phase line identification strategy

[0083] The intelligent devices of the power distribution Internet of Things provide data support for the identification of the phase line relationship of the transformer area. Through HPLC, MQTT, CoAP, etc. of the transformer area, data transmission is realized. HPLC is widely used in low-voltage distribution networks due to its high communication rate, small transmission delay, strong anti-noise interference ability and other characteristics. However, the low-voltage distribution network line environment is complex, and HPLC is easily affected by long node distance. Generally, LTU is used as a relay node for HPLC communication to establish normal communication connection. Relying on the existing equipment of the transformer area, based on the characteristic signals sent by HPLC, the identification of the user phase line relationship is realized. No additional equipment needs to be added, which is conducive to cost saving. However, due to environmental or phased construction, LTU has not been installed in some areas or HPLC communication mode has not been adopted. Therefore, a single identification method cannot realize the identification of the entire transformer area phase line relationship.

[0084] For areas where LTU equipment is installed and LTU is operating normally, if the substation is configured with HPLC communication, a phase line relationship identification method based on HPLC communication can be used. If HPLC communication is not configured, the acquisition module reads the user's meter data based on the RS-485 bus, and can transmit the data to the data concentrator through the local channel (RS-485, CANBUS bus or hybrid networking, etc.). The data concentrator uses a remote channel (GPRS, optical fiber, etc.) to transmit the user's electricity consumption data to the main station. Therefore, in areas where HPLC is not configured, the user's meter voltage correlation analysis can be performed based on the k-means algorithm to realize the identification of the user's phase line relationship. The specific phase line identification strategy flow chart is as follows: Figure 6 shown.

[0085] S4: Topological identification of phase line relationships in unknown areas

[0086] In the area where HPLC is configured, the phase line relationship can be identified based on HPLC. The TTU is used as the access head end (CCO), the LTU is used as the relay node (PCO), and the smart meter, temperature sensor, etc. are used as the access terminal (STA). This forms the HPLC communication network topology. Its structure is similar to the low-voltage distribution network topology and can meet the needs of line communication coverage. The corresponding communication structure diagram is shown in the figure below. Figure 7 As shown in the figure, the TTU and LTU have completed the time synchronization. The TTU sends a zero-crossing time request to Ln through the LTU. After receiving the zero-crossing time from Ln, it compares it with its own three-phase zero-crossing time. The closest one is the phase line connected to Ln.

[0087] If HPLC is not configured in the substation, phase line identification can be performed using k-means. When performing clustering, the initial number of clusters is set, followed by the selection of initial centroids and the calculation of voltage correlation using the Pearson correlation coefficient method. The specific process is shown in Figure 8.

[0088] Select the user voltage data of the actual low-voltage distribution area, set the unknown area, and determine the actual topological line of the area. When individual sampling points of users fail, the value at time t-1 is used to fill in the voltage data to complete the voltage data. By analyzing a large number of voltage data samples, the accuracy of judging the correlation only by the voltage data of a certain day is low. It is necessary to perform k-means cluster analysis on the voltage data of a period of time to determine the topological relationship. Cluster analysis is performed on the user voltage data of some areas of the three areas respectively. The recognition results of each phase line in each area are as follows: Figure 9As shown. For unknown areas configured with HPLC, the user phase line relationship is identified based on HPLC, and the accuracy of phase line relationship identification can reach 100%. For areas not configured with HPLC, the average recognition accuracy based on k-means is 93.96%. The present invention uses the data of the nodes in the upper layer of the unknown area for analysis, which is closer in electrical distance and has higher clustering accuracy. Phase line relationship identification is only performed in unknown areas, avoiding waste of resources. In addition, the regional identification strategy is adopted, and the nearest identification avoids the influence of the cluster center of the k-means algorithm, thereby improving the accuracy of clustering.

[0089] like Figure 10 As shown, this embodiment also provides a low-voltage distribution network phase line topology identification system, including:

[0090] The area determination module is used to analyze the phase-line relationship based on a graph theory model and determine the known and unknown areas of the substation area based on the installation and operation status of the LTU and whether the line topology is known;

[0091] Phase line identification module, used to: identify the entire phase line in the substation based on the analysis results;

[0092] The phase line relationship configuration module is used to: configure the phase line relationship of the known area according to the recognition result; and configure the phase line relationship after converting the unknown area into the known area.

[0093] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions to the transaction features between nodes without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for identifying phase line topology of a low-voltage distribution network, characterized in that: The following steps are involved: S1: Analyze the phase-line relationship based on a graph theory model and determine the known and unknown areas of the substation based on the installation and operation status of the LTU and whether the line topology is known; S2: Based on the recognition result of step S1, configure the phase line relationship of the known area in step S1; S3: Based on the analysis results in step S1, identify the overall phase line topology relationship in the substation area; S4: According to the recognition result of step S3, the unknown area in step S1 is configured with a phase line relationship based on step S2.

2. A low-voltage distribution network phase line topology identification method according to claim 1, characterized in that: The step S1 includes: The low-voltage distribution network lines are abstracted as a collection of low-voltage distribution network edges and nodes. The relationship between topological blocks is reflected through the connection relationship between nodes and edges, and between nodes in the network structure diagram. Based on graph theory, the low-voltage distribution network phase line relationship topology is modeled as a four-tuple. The physical model of nodes, edges, and switch states is converted into a mathematical model of transformers, edges, and switches. Based on the graph theory model, the known and unknown areas of the substation are determined according to the installation and operation status of the LTU and whether the line topology is known.

3. A low-voltage distribution network phase line topology identification method according to claim 2, characterized in that: Based on graph theory, the four-tuple of low-voltage distribution network line topology is established = (V, E, S, X). The set of nodes, edges, switches, and commutation switches of the low-voltage distribution network line are represented as V G ={v1, v2, ..., v n }、E G ={e1, e2, ..., e m }、S k ∈[0,1],X i ∈[0, 1], where e k ∈[1,3], when the value is 1, it indicates a single-phase line, when the value is 3, it indicates a three-phase line, S k =0, indicating the switch is off, S k =1, indicating that the switch is closed. If commutation occurs, then X i It changes to 1 and performs topology update. After the update, it changes to 0 and performs the corresponding action after the next phase change. Map the phase line topology of the substation area into the network structure diagram G, E total →G total , where e∈E total , g∈G total , map(e)=g means that any low-voltage phase line relationship topology diagram can be represented by a network structure diagram; The transformer node is taken as the root node, the terminal load or DER is taken as the leaf node, and the node where the line intersects is taken as the branch node. If the area is monitored by n LTUs, the known and unknown areas of the substation are determined based on the installation and operation status of the LTUs and whether the line topology is known. The low-voltage line is divided into n small areas according to the monitoring range of the LTUs. For graph G, it is divided into n subgraphs.

4. A method for identifying a phase line topology of a low-voltage distribution network according to claim 1, characterized in that: The step S2 comprises the following steps: S21: Add the Line container of the low-voltage distribution network to the low-voltage area to describe the lines between substations; S32: The segmented lines between the devices in the low-voltage distribution station use the Line container of the low-voltage distribution network, and the upper layer uses a Process container to represent the entire substation; S33: The switches of the line are described using Substation containers; S34: Add the phases attribute to increase the configuration of the phase line of the substation line topology; S35: Steps S21-S24 build a hierarchical model of the low-voltage distribution network topology based on IEC 61850SCL, configure lines according to the divided areas, and represent an area using a Substation container.

5. A method for identifying phase line topology of a low-voltage distribution network according to claim 1, characterized in that: The step 3 comprises the following steps: S31: If there are users in the substation area with known phase-line relationships, the phase-line relationships are configured based on IEC 61850 SCL, and the substation area line topology is divided into unknown areas according to step S1; S32: For areas where LTU equipment is installed and the LTU is operating normally, if the substation is configured with HPLC communication, the phase line relationship based on HPLC communication is used for identification; S33: For areas where HPLC is not configured, user meter voltage correlation analysis is performed based on the k-means algorithm to identify user phase-line relationships. S34: After the phase-line relationship of users in the unknown area is identified, the phase-line relationship is configured based on IEC 61850 SCL.

6. A method for identifying phase line topology of a low-voltage distribution network according to claim 1, characterized in that: The step S4 is specifically as follows: for unknown areas configured with HPLC, phase line relationships are identified based on HPLC; for unknown areas not configured with HPLC, correlation analysis between voltage measurements is performed based on k-means clustering before phase line identification.

7. A method for identifying phase line topology of a low-voltage distribution network according to claim 6, characterized in that: The k-means clustering includes: Set the initial number of clusters; Select the initial centroid; Voltage correlations were calculated according to the Pearson correlation coefficient method.

8. A method for identifying phase line topology of a low-voltage distribution network according to claim 7, characterized in that: Select the user voltage data of the actual low-voltage distribution area, set the unknown area, and determine the actual topology line of the distribution area; When a user sampling point fails, the value at time t-1 is used to fill in the voltage and data. By analyzing the voltage data samples and performing k-means cluster analysis on the voltage data over a period of time, the phase line topology relationship can be determined.

9. An identification system based on the low-voltage distribution network phase line topology identification method according to claim 1, characterized in that: include: The area determination module is used to analyze the phase-line relationship based on a graph theory model and determine the known and unknown areas of the substation area based on the installation and operation status of the LTU and whether the line topology is known; Phase line identification module, used to: identify the entire phase line in the substation based on the analysis results; Phase line relationship configuration module, used to: configure phase line relationship for known areas based on identification results; The phase line relationship identification results of the unknown area are used to configure the phase line relationship.

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