A method and system for identifying substation topology based on Kirchhoff's law

Abstract

The present invention discloses a method and system for identifying a substation topology based on Kirchhoff's law, and relates to the technical field of low-voltage substation topology identification, including obtaining low-voltage rural power substation LMU and household meter data and preprocessing; for LMU data, establishing an LMU-LMU identification relationship model based on Kirchhoff's law; based on the order of LMU load from high to low, establishing an LMU-LMU relationship model based on Kirchhoff's law for the LMU to be compared with the LMU in the existing LMU-LMU topological structure one by one, and obtaining the real position of the LMU to be compared in the LMU-LMU structure; establishing an LMU-household meter identification relationship model; based on the identified complete LMU-LMU structure, for each household meter, establishing an LMU-household meter identification model based on Kirchhoff's law with all LMUs, and finally determining the LMU to which the current household meter belongs. In the scenario of power topology identification based on data analysis, the present invention has the advantages of reducing the input of resources such as manpower and material resources, and can ensure the accuracy of topology identification, forming a substation topology identification system with both low cost and high efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of low-voltage rural power grid area topology identification, and in particular to a method and system for identifying area topology based on Kirchhoff's law. Background Art

[0002] The topological identification of the rural power grid area with LMU installed refers to the installation of LMU equipment at the T-junction part of the main cable in the rural power grid area frame in view of the particularity of power distribution in the rural power grid area and the complexity of the line topology, so that it has the function of monitoring and measuring the voltage, current, power factor and active power indication at each T-junction of the rural power grid area line. Based on the LMU collection data and the household meter data of the station area, the rural power grid area is built with the installed LMU as the skeleton, and based on Kirchhoff's law, the physical model between LMU-LMU and between LMU-household meter is established respectively. The line resistance and model fitting effect are solved by the least squares method. Through the judgment of the model solution, the topological relationship between LMU-LMU and the topological relationship between LMU-household meter in the rural power grid area with LMU as the skeleton and household meter as the leaf are identified. This patent mainly relates to the system method of LMU-LMU topological identification and LMU-household meter relationship identification in the rural power grid area with LMU installed.

[0003] There are currently three main technologies for identifying the topological relationship of rural power grid areas with LMUs installed: manual survey method, characteristic current method and carrier ranging method. The manual survey method is to manually survey the lines and meters after the rural power grid area is installed with LMUs, and match the relationship between LMU-LMU-household meters one by one based on the line topology tracking; the characteristic current method is to replace the HPLC-STA communication unit with the characteristic current transmission function for the electric energy meter, install the LMU equipment with the characteristic current transmission and detection function for the LMU, and install the energy controller on the low-voltage outlet side of the transformer. The LMU-LMU-household meter topological relationship is constructed from bottom to top based on the characteristic signal; the carrier ranging method is similar to the characteristic current method, that is, the existing HPLC-STA communication unit is upgraded in software, and the attenuation and signal-to-noise ratio characteristics of the PLC signal are used. By comparing the differences between the nodes within the cluster and the nodes outside the cluster, the PLC ranging realizes the measurement of the node distance and the recognition of the LMU-LMU-household meter relationship using the "minimum spanning tree" algorithm.

[0004] Among the above-mentioned existing technologies, the manual survey method is the most direct, but the labor cost is high. At the same time, for complex rural substations, the line relationship is complex and the location of the electric meter is hidden. It is difficult to understand the entire topology by manual survey alone; the characteristic current method requires the replacement of the electric meter STA hardware, which is costly. At the same time, for situations where the location of the electric meter is hidden and difficult to reach, a large amount of labor cost is still required; the carrier ranging method has high requirements on the stability of the carrier signal. For substations with large line noise and deep topological communication levels, the recognition accuracy is low. Summary of the invention

[0005] In view of the above-mentioned existing problems, the present invention is completely based on the voltage and current data collected by the LMU and household meters installed in the low-voltage rural power grid area. By establishing a physical model based on Kirchhoff's law, the low-voltage rural power grid area LMU-LMU-household meter identification is completed through model analysis. Compared with the existing methods, the present invention does not require human intervention after the installation of the LMU. It only relies on data, physical principles and mathematical modeling to solve the problem, and can complete the topology identification of the rural power grid area to achieve the purposes of low labor cost, high identification efficiency and high identification accuracy.

[0006] In order to solve the above technical problems, a method for identifying substation topology based on Kirchhoff's law is proposed, including:

[0007] Obtain the LMU and household meter data in the low-voltage rural power grid area and preprocess them; for the LMU data, establish an LMU-LMU identification relationship model based on Kirchhoff's law; based on the order of LMU load from high to low, establish an LMU-LMU relationship model based on Kirchhoff's law for the LMU to be compared with the LMU in the existing LMU-LMU topological structure one by one, and based on the model return results, obtain the true position of the LMU to be compared in the LMU-LMU structure; based on Kirchhoff's law, establish an LMU-household meter identification relationship model; based on the identified complete LMU-LMU structure, for each household meter, establish an LMU-household meter identification model based on Kirchhoff's law with all LMUs, and finally determine the LMU to which the current household meter belongs.

[0008] As a preferred solution of the method for identifying substation topology based on Kirchhoff's law described in the present invention, the data includes the voltage and current data of all electric energy meters in the substation. After acquiring the data, the empty data is removed so that the current and voltage data of the LMU and each electric energy meter do not contain empty points, and all the empty value data and abnormal data of the voltage and current of the electric energy meter are deleted so that the voltage and current data of each electric energy meter are aligned according to the time series.

[0009] As a preferred solution of the area topology identification method based on Kirchhoff's law described in the present invention, the LMU-LMU identification relationship model includes: for any two LMUs, the position relationship based on the topology is divided into a bifurcation type and an up-down type, and an LMU-LMU identification relationship model based on Kirchhoff's law is established. , and high-frequency voltage and current data, establish a regression equation and analyze the solved resistance and sign to determine the positional relationship between any two LMUs.

[0010] As a preferred solution of the method for identifying the substation topology based on Kirchhoff's law described in the present invention, the real location includes: based on the LMU-LMU identification relationship model, initializing the LMU-LMU structure to be empty, arranging the LMU meters from large to small based on the average value of the high-frequency current of the LMU meters, and placing the arranged list one by one By comparing with the LMU in the existing LMU-LMU structure, the LMU-LMU identification relationship model is established to obtain the real position of the LMU-LMU topology.

[0011] As a preferred solution of the method for identifying the substation topology based on Kirchhoff's law described in the present invention, the LMU-household meter identification relationship model includes: when the household meter M is under any LMU, according to Kirchhoff's law, the LMU voltage is set to , the voltage and current of the household meter are , , the resistance between the meter and LMU is R, then there is a relationship: ,Right now , for a household meter M and a LMU meter, based on the LMU high-frequency voltage , household meter high frequency voltage and current , , establish the regression equation:

[0012] ,

[0013] Based on the least squares method, the best estimated value ẑ of the unknown variable z and the goodness of fit S of the regression equation are solved, where the solved ẑ is the resistance between LMU and household meter, and the goodness of fit S is the model formula for evaluating the LMU and current household meter data. The fitting effect of , where the goodness of fit S is calculated as follows:

[0014] ,

[0015] in, , are the average values ​​of the voltage curves of the LMU meter and the household meter, , are the values ​​on the voltage curve of the i-th LMU meter and household meter, is the current value of the ith household meter.

[0016] When the value of ẑ is within the range of 0–1 ohm and the goodness of fit S>0.9, it means that the current LMU and household meter data have a good explanation effect on the model formula, that is, the actual location of the current household meter is under the current LMU.

[0017] When the ẑ value is negative or the ẑ value is greater than 1 ohm or the goodness of fit S is less than 0.3, it means that the current LMU and household meter data have a poor interpretation effect on the model formula, that is, the actual location of the current household meter is not under the current LMU.

[0018] As a preferred solution of the method for identifying the topology of a substation area based on Kirchhoff's law described in the present invention, wherein: the determination of the LMU to which the current household meter belongs includes, based on the LMU-household meter identification relationship model and the LMU-LMU topology real position identification process generated LMU-LMU structure, for all household meter sets in the substation area Each household in High frequency voltage and current data , , respectively, with each of the LMU-LMU structures obtained in the real location identification process of the LMU-LMU topology (i=1,2,3,…) high frequency voltage data , establish the LMU-household table identification relationship model and solve it, and obtain the household table M and all Estimated resistance of (i=1,2,3,…) and goodness of fit S, excluding unreasonable estimated resistance ,when <0 or >1, the remaining LMU candidate set is , select the solution with the highest goodness of fit S , which is the current household table The LMU branch to which it belongs.

[0019] Another object of the present invention is to provide a substation topology identification system based on Kirchhoff's law. The present invention aims to achieve accurate identification of the electrical topology structure of the low-voltage rural power substation through technical means, establish an LMU-LMU identification relationship model to distinguish between bifurcated and up-down relationships, and determine the true position of the LMU in the topology structure one by one, so as to provide detailed and accurate topology information for the operation and maintenance of the power system, and facilitate fault analysis, load management, energy efficiency optimization and other operations; establish an LMU-household meter identification relationship model by analyzing the high-frequency voltage data of the LMU and the household meter, and solve the estimated resistance and goodness of fit of the household meter and the LMU, finally eliminate unreasonable estimates, determine the LMU branch to which each household meter belongs, thereby accurately identifying the electrical topology structure of the entire substation, and providing detailed and accurate basic data support for the stable operation, maintenance and management of the power system; improve the management efficiency of the power system, reduce misoperation and energy waste caused by unclear topology, and ensure the stability and safety of power supply.

[0020] As a preferred solution of the substation topology identification system based on Kirchhoff's law described in the present invention, it is characterized by including a data preprocessing module, an LMU-LMU identification module, an LMU-LMU position identification module, an LMU-household meter identification establishment module, and a household meter determination module.

[0021] The data preprocessing module collects the voltage and current data of all electric energy meters in the substation area. It removes empty data and abnormal data to ensure that the current and voltage data of LMU and each electric energy meter are complete and aligned according to the time series. It performs multipath interference optimization and builds a network current distribution model.

[0022] The LMU-LMU identification module, based on Kirchhoff's law, classifies the positional relationship between any two LMUs into bifurcated type and up-down type, and establishes a corresponding mathematical model.

[0023] The LMU-LMU position identification module initializes the LMU-LMU structure to be empty, sorts the LMU meters according to the average value of the high-frequency current, compares them one by one with the LMUs in the existing LMU-LMU structure, and determines the real position of each LMU in the LMU-LMU structure.

[0024] The LMU-household meter identification establishment module establishes an LMU-household meter identification model for each household meter and a certain LMU based on Kirchhoff's law, and solves the resistance and goodness of fit between the LMU and the household meter through a regression equation.

[0025] The household meter determination module compares the high-frequency voltage and current data of each household meter with each LMU in the LMU-LMU structure based on the LMU-household meter identification relationship model and the actual position of the LMU-LMU topology to determine the LMU to which the household meter belongs.

[0026] As a preferred solution of the substation topology identification system based on Kirchhoff's law described in the present invention, the data preprocessing module includes: the data preprocessing module collects voltage and current data of all LMUs, i.e. line monitoring units, and household meters, i.e. residential electric energy meters, from the low-voltage rural power grid in the substation area; after the data collection is completed, the data preprocessing module cleans the data, including removing empty data and abnormal data, and aligning the data in time series to ensure that the timestamp of each data point is consistent; the data preprocessing module performs multipath interference optimization and constructs a network current distribution model; the output result of the data preprocessing module is input into the LMU-LMU identification module; the LMU-LMU identification module receives the preprocessed data, and according to Kirchhoff's law, identifies any two LMUs The topological position relationship between them is classified. For each topological relationship, the module establishes a corresponding mathematical model. After the model is established, the model is passed to the LMU-LMU position identification module; after the LMU-LMU position identification module determines the position of the LMU, the module outputs a complete LMU-LMU topological structure, which is input into the LMU-household meter identification module for use; the LMU-household meter identification module receives the LMU-LMU topological structure and household meter data, and establishes an identification model for each household meter and LMU based on Kirchhoff's law. The module outputs the resistance estimation value and goodness of fit between each household meter and LMU, and passes it to the household meter determination module; the household meter determination module receives the result of the LMU-household meter identification module, outputs the LMU to which each household meter belongs, and completes the identification of the entire substation area topology.

[0027] A computer device includes a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the computer program, the steps of a method for identifying a substation topology based on Kirchhoff's law are implemented.

[0028] A computer-readable storage medium having a computer program stored thereon, characterized in that when the computer program is executed by a processor, the steps of a method for identifying a substation topology based on Kirchhoff's law are implemented.

[0029] Beneficial effects of the present invention: The present invention can be applied to power topology identification scenarios. In power topology identification scenarios based on data analysis, it has the advantages of reducing the input of resources such as manpower and material resources and ensuring the accuracy of topology identification.

[0030] The system cleans the collected LMU and household meter data through the data preprocessing module, including removing outliers and aligning time series, which significantly improves the quality and availability of the data. This provides accurate basic data for subsequent topology identification and reduces identification errors caused by data quality issues; by establishing an LMU-LMU identification relationship model, the system can distinguish between bifurcated and up-and-down relationships and accurately identify the connection relationship between LMUs. This method based on Kirchhoff's law can effectively handle complex network structures and ensure the accuracy of topology identification; the system determines the true position of the LMU in the topology structure, so that when a power failure occurs, the fault point can be quickly located, the fault processing time can be reduced, and the operation and maintenance efficiency of the power grid can be improved.

[0031] Starting from the circuit principles and basic laws of electricity, the present invention proposes a topology identification method based on machine learning search, solution and evaluation. Compared with the existing methods, the present invention has the characteristics of practicality, simplicity and strong scalability, forming a substation topology identification system with both low cost and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0033] Figure 1 A schematic diagram of the steps of a rural power grid area LMU-LMU-household meter identification system method for an area topology identification method based on Kirchhoff's law provided in one embodiment of the present invention.

[0034] Figure 2 An embodiment of the present invention provides a method for identifying a substation topology based on Kirchhoff's law, which is based on the position relationship of the LMU in the topology - bifurcation type.

[0035] Figure 3 An embodiment of the present invention provides a method for identifying a substation topology based on Kirchhoff's law, which is based on the topological position relationship of LMU - up and down type.

[0036] Figure 4 An LMU-LMU topology diagram of a substation topology identification method based on Kirchhoff's law is provided in one embodiment of the present invention.

[0037] Figure 5 An embodiment of the present invention provides a method for identifying a substation topology based on Kirchhoff's law, which includes a LMU topology-based position relationship-household meter model diagram.

[0038] Figure 6 A system solution module diagram of a substation topology identification system based on Kirchhoff's law provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0040] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0041] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive with other embodiments, either individually or selectively.

[0042] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0043] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0044] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] Example 1, reference Figure 1-Figure 3 , which is the first embodiment of the present invention, and provides a method for identifying a substation topology based on Kirchhoff's law, comprising:

[0046] S1: Obtain the LMU and household meter data in the low-voltage rural power grid area and pre-process them.

[0047] Furthermore, the voltage and current data of all the electric energy meters in the substation area are collected. After acquiring the data, the empty data is eliminated so that the current and voltage data of the LMU and each electric energy meter do not contain empty points, and all the empty value data and abnormal data of the voltage and current of the electric energy meter are deleted so that the voltage and current data of each electric energy meter are aligned according to the time series.

[0048] It should be noted that after aligning the voltage and current data according to the time series, multipath interference optimization is performed, and the network current distribution model is constructed. The entire current network is displayed by graph theory, with A nodes and B edges set, and each edge There is current on and resistor :

[0049] ,

[0050] in, Point at the edge The current flowing on refers to the voltage at nodes a and b, Finger edge The resistance of the network, A is the total number of nodes in the network, and B is the total number of edges in the network;

[0051] Calculate the current input and output at each node:

[0052] ,

[0053] ,

[0054] in, For Node The inflow current, For Node The outflow current, c and d are nodes;

[0055] Constructing the current aggregation quality function , through the combined optimization algorithm to minimize the current loss of the entire network, forming the objective function ,in, is the loss coefficient, the influence degree of node b; at the same time, the constraint conditions are used to ensure current conservation , a nonlinear regression model is built based on the historical data of current flow:

[0056] ,

[0057] in, is the time variable, , , are the parameters in the nonlinear dynamic response model, is the frequency, for The current value at

[0058] Building a multi-objective optimization framework:

[0059] ,

[0060] in, , is the weight coefficient of different objectives in the comprehensive model.

[0061] S2: For LMU data, an LMU-LMU identification relationship model based on Kirchhoff’s law is established.

[0062] Furthermore, Figure 2-Figure 3 As shown, any two LMUs are divided into bifurcated type and up-down type based on the topological position relationship. The bifurcated type is that the two LMUs in the low-voltage rural power line have a common upper T-connection point, and the up-down type includes that one LMU is located at the lower level of another LMU.

[0063] For the bifurcated topological relationship between two LMUs, based on Kirchhoff's law, we get:

[0064] ,

[0065] Arrange to get formula 1:

[0066] ,

[0067] in, , is the LMU voltage on the left and right sides, , is the LMU current on the left and right sides, , The resistors on the left and right sides.

[0068] For the up-and-down topological relationship between two LMUs, based on Kirchhoff's law, we get:

[0069] ,

[0070] After sorting, we get formula 2:

[0071] ,

[0072] in, , is the LMU voltage at the upper and lower ends, , is the LMU current at the upper and lower ends, , The resistance at the upper and lower ends.

[0073] For any two , And high frequency voltage and current data , , , , establish the regression equation:

[0074] ,

[0075] Where x and y are the resistances and their symbols to be solved.

[0076] Analyze the signs of x and y and Formula 1 and Formula 2: When x is a negative number and y is a positive number, solve the resistance and sign to satisfy the form of the resistance and sign in Formula 1. , It is a bifurcation relationship. When x is a positive number and y is a positive number, the resistance and symbol satisfy the form of the resistance and symbol in formula 2, indicating , It is a top-down relationship.

[0077] S3: Based on the order of LMU load from high to low, establish an LMU-LMU relationship model based on Kirchhoff's law for the LMU to be compared and the LMU in the existing LMU-LMU topology structure one by one, and obtain the actual position of the LMU to be compared in the LMU-LMU structure based on the result returned by the model.

[0078] Furthermore, based on the LMU-LMU identification relationship model, the LMU-LMU structure is initialized to be empty, and the LMU meters are arranged from large to small based on the average value of the high-frequency current of the LMU meters, and the arranged lists are listed one by one. By comparing with the LMU in the existing LMU-LMU structure, the LMU-LMU identification relationship model is established to obtain the real position of the LMU-LMU topology.

[0079] S4: Based on Kirchhoff’s law, establish the LMU-user table identification relationship model.

[0080] Furthermore, when the user meter M is under any LMU, according to Kirchhoff's law, the LMU voltage is set to , the voltage and current of the household meter are , , the resistance between the meter and LMU is R, then there is a relationship: ,Right now , for a household meter M and a LMU meter, based on the LMU high-frequency voltage , household meter high frequency voltage and current , , establish the regression equation:

[0081] ,

[0082] Based on the least squares method, the best estimated value ẑ of the unknown variable z and the goodness of fit S of the regression equation are solved, where the solved ẑ is the resistance between LMU and household meter, and the goodness of fit S is the model formula for evaluating the LMU and current household meter data. The fitting effect of , where the goodness of fit S is calculated as follows:

[0083] ,

[0084] in, , are the average values ​​of the voltage curves of the LMU meter and the household meter, , are the values ​​on the voltage curve of the i-th LMU meter and household meter, is the current value of the ith household meter;

[0085] When the value of ẑ is within the range of 0-1 ohm and the goodness of fit S>0.9, it means that the current LMU and household meter data have a good explanation effect on the model formula, that is, the actual position of the current household meter is under the current LMU;

[0086] When the ẑ value is negative or the ẑ value is greater than 1 ohm or the goodness of fit S is less than 0.3, it means that the current LMU and household meter data have a poor interpretation effect on the model formula, that is, the actual location of the current household meter is not under the current LMU.

[0087] S5: Based on the identified complete LMU-LMU structure, for each household meter, an LMU-household meter identification model based on Kirchhoff's law is established with all LMUs, and finally the LMU to which the current household meter belongs is determined.

[0088] Furthermore, the LMU-LMU structure generated by the real location identification process based on the LMU-household meter identification relationship model and the LMU-LMU topology is used for all household meter sets in the substation area. Each household in High frequency voltage and current data , , respectively, with each of the LMU-LMU structures obtained in the real location identification process of the LMU-LMU topology (i=1,2,3,…) high frequency voltage data , establish the LMU-household table identification relationship model and solve it, and obtain the household table M and all Estimated resistance of (i=1,2,3,…) and goodness of fit S, excluding unreasonable estimated resistance ,when <0 or >1, the remaining LMU candidate set is , select the solution with the highest goodness of fit S , which is the current household table The LMU branch to which it belongs.

[0089] The LMU-LMU model based on Kirchhoff's law, the establishment of the LMU-household meter model, and the LMU-LMU, LMU-household meter identification process. The present invention is different from the prior art that adds redundant collection functions to the meter or LMU. It only needs the collection functions of the meter and LMU, and can complete the LMU-LMU-household meter identification through data analysis methods.

[0090] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0091] Example 2, reference Figure 1 , Figure 4-Figure 5 , which is the first embodiment of the present invention, and provides a method for identifying a substation topology based on Kirchhoff's law, comprising:

[0092] S1: Obtain the LMU and household meter data in the low-voltage rural power grid area and pre-process them.

[0093] Furthermore, collect the voltage and current data of all the electricity meters in the collection area. After obtaining the data, eliminate the null data so that the current and voltage data of the LMU and each electricity meter do not contain null points, and delete all the null value data and abnormal data of the voltage and current of the electricity meters, so that the voltage and current data of each electricity meter are aligned according to the time series.

[0094] S2: For the LMU data, establish an LMU-LMU recognition relationship model based on Kirchhoff's law.

[0095] Furthermore, for any two LMU, the topological positional relationships are divided into bifurcated type and upper-lower type. Establish an LMU-LMU recognition relationship model based on Kirchhoff's law. For any two and high-frequency voltage and current data, establish a regression equation and analyze and solve the resistance and sign to judge the positional relationship between any two LMU.

[0096] S3: Based on the order of the LMU load from high to low, one by one establish an LMU-LMU relationship model based on Kirchhoff's law between the LMU to be compared and the LMU in the existing LMU-LMU topological structure. Based on the result returned by the model, obtain the true position of the LMU to be compared in the LMU-LMU structure.

[0097] Furthermore, as Figure 4 shown, based on the LMU-LMU recognition relationship model, initialize the LMU-LMU structure to be empty, and arrange the LMU electricity meters in descending order of the average value of the high-frequency electric current of the LMU electricity meters as a list , where n is the total number of LMU electricity meters after sorting. One by one compare the in the list with the LMU in the existing LMU-LMU structure. Set the list of LMU in the identified LMU-LMU structure as , and the LMU whose position is to be confirmed is . Then establish the LMU-LMU recognition relationship model between and : When for any electricity meter sorting k < j, and are in the upper-lower type relationship, then is under , and stop traversing.

[0098] When all the identified LMU are in a bifurcated type relationship with , then and are in a bifurcated type relationship.

[0099] Repeat the above process to obtain the true position of the LMU-LMU topology.

[0100] S4: Based on Kirchhoff’s law, establish the LMU-user table identification relationship model.

[0101] Furthermore, Figure 5 As shown, when the user meter M is under any LMU, according to Kirchhoff's law, the LMU voltage is set to , the voltage and current of the household meter are , , the resistance between the meter and LMU is R, then there is a relationship: ,Right now , for a household meter M and a LMU meter, based on the LMU high-frequency voltage , household meter high frequency voltage and current , , establish the regression equation:

[0102] ,

[0103] Based on the least squares method, the best estimated value ẑ of the unknown variable z and the goodness of fit S of the regression equation are solved, where the solved ẑ is the resistance between the LMU and the household meter, and the goodness of fit S is used to evaluate the model formula for the LMU and the current household meter data. The fitting effect of , where the goodness of fit S is calculated as follows:

[0104] ,

[0105] in, , are the average values ​​of the voltage curves of the LMU meter and the household meter, , are the values ​​on the voltage curve of the i-th LMU meter and household meter, is the current value of the ith household meter.

[0106] When the value of ẑ is within the range of 0–1 ohm and the goodness of fit S>0.9, it means that the current LMU and household meter data have a good explanation effect on the model formula, that is, the actual location of the current household meter is under the current LMU.

[0107] When the ẑ value is negative or the ẑ value is greater than 1 ohm or the goodness of fit S is less than 0.3, it means that the current LMU and household meter data have a poor interpretation effect on the model formula, that is, the actual location of the current household meter is not under the current LMU.

[0108] S5: Based on the identified complete LMU-LMU structure, for each household meter, an LMU-household meter identification model based on Kirchhoff's law is established with all LMUs, and finally the LMU to which the current household meter belongs is determined.

[0109] Furthermore, the LMU-LMU structure generated by the real location identification process based on the LMU-household meter identification relationship model and the LMU-LMU topology is used for all household meter sets in the substation area. Each household in High frequency voltage and current data , , respectively, with each of the LMU-LMU structures obtained in the real location identification process of the LMU-LMU topology (i=1,2,3,…) high frequency voltage data , establish the LMU-household table identification relationship model and solve it, and obtain the household table M and all Estimated resistance of (i=1,2,3,…) and goodness of fit S, excluding unreasonable estimated resistance ,when <0 or >1, the remaining LMU candidate set is , select the solution with the highest goodness of fit S , which is the current household table The LMU branch to which it belongs.

[0110] The present invention has been applied on a small scale in some rural power grid areas where LMUs are installed. By collecting household meters and LMU voltage and current data, the output of the LMU-LMU-household meter results in the substation area is calculated and compared with the actual results. The accuracy of the LMU-LMU-household meter recognition topology and the actual topology is 100%, which proves the feasibility of the method.

[0111] Embodiment 3, the third embodiment of the present invention, is different from the first two embodiments in that:

[0112] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0113] The logic and / or steps represented in the flowchart or otherwise described herein can, for example, be considered as a definitional sequence of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.

[0114] More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection (electronic device) having one or more wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, as the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or otherwise processing as appropriate, and then storing it in a computer memory.

[0115] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), and the like.

[0116] Example 4, referring to Figure 6 , is the fourth embodiment of the present invention. This embodiment provides a substation area topology identification system based on Kirchhoff's law, including a data preprocessing module, an LMU-LMU identification module, an LMU-LMU position identification module, an LMU-household meter identification and establishment module, and a household meter determination module.

[0117] The data preprocessing module collects the voltage and current data of all the electric energy meters in the substation area; removes empty data and abnormal data to ensure that the current and voltage data of the LMU and each electric energy meter are complete and aligned according to the time series; performs multi-path interference optimization and builds a network current distribution model.

[0118] The LMU-LMU identification module, based on Kirchhoff's law, classifies the positional relationship between any two LMUs into bifurcation type and up-down type, and establishes the corresponding mathematical model.

[0119] The LMU-LMU position identification module initializes the LMU-LMU structure to be empty, sorts the LMU meters according to the average value of the high-frequency current, compares them one by one with the LMUs in the existing LMU-LMU structure, and determines the true position of each LMU in the LMU-LMU structure.

[0120] The LMU-household meter identification establishment module establishes an LMU-household meter identification model for each household meter and a certain LMU based on Kirchhoff's law, and solves the resistance and goodness of fit between LMU and household meter through regression equation.

[0121] The household meter determination module compares the high-frequency voltage and current data of each household meter with each LMU in the LMU-LMU structure based on the LMU-household meter identification relationship model and the actual position of the LMU-LMU topology to determine the LMU to which the household meter belongs.

[0122] Specifically, the data preprocessing module collects the voltage and current data of all LMUs, i.e. line monitoring units, and household meters, i.e. residential electricity meters, from the low-voltage rural power grid in the substation area. After the data collection is completed, the data preprocessing module cleans the data, including removing empty data and abnormal data, and aligning the data in time series to ensure that the timestamp of each data point is consistent; the data preprocessing module optimizes multipath interference and builds a network current distribution model; the output results of the data preprocessing module are input into the LMU-LMU identification module; the LMU-LMU identification module receives the preprocessed data, and classifies the topological position relationship between any two LMUs according to Kirchhoff's law. For each topological relationship The module establishes the corresponding mathematical model. After the model is established, the model is passed to the LMU-LMU position identification module; after the LMU-LMU position identification module determines the location of the LMU, the module outputs the complete LMU-LMU topology structure, which is input into the LMU-household meter identification module for use; the LMU-household meter identification module receives the LMU-LMU topology structure and household meter data, and establishes an identification model for each household meter and LMU based on Kirchhoff's law. The module outputs the resistance estimation value and goodness of fit between each household meter and LMU, and passes it to the household meter determination module; the household meter determination module receives the result of the LMU-household meter identification module, outputs the LMU to which each household meter belongs, and completes the identification of the entire substation topology.

[0123] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for identifying substation topology based on Kirchhoff's law, characterized by: include, Obtain the LMU and household meter data in the low-voltage rural power grid area and perform pre-processing; For LMU data, an LMU-LMU identification relationship model based on Kirchhoff’s law is established; For any two LMUs, the positional relationship based on the topology is divided into a bifurcated type and an upper-lower type. The bifurcated type is that the two LMUs in the low-voltage rural power line have a common upper-level T-connection point, and the upper-lower type includes that one LMU is located at the lower level of another LMU. For the bifurcated topological relationship between two LMUs, based on Kirchhoff's law, we get: U1+I1×R1=U2+I2×R2 Arrange to get formula 1: U1-U2=I1×(-R1)+I2×R2 Among them, U1 and U2 are the LMU voltages on the left and right sides, I1 and I2 are the LMU currents on the left and right sides, and R1 and R2 are the resistances on the left and right sides; For the up-and-down topological relationship between two LMUs, based on Kirchhoff's law, we get: U'2+I'2×R'2+I'1×R'1=U'1 Arrange to get formula 2: U'1-U'2=I'1×R'1+I'2×R'2 Among them, U′1 and U′2 are LMU voltages at the upper and lower ends, I′1 and I′2 are LMU currents at the upper and lower ends, and R′1 and R′2 are resistances at the upper and lower ends; For any two LMU1, LMU2 and high-frequency voltage and current data U1, I1, U2, I2, a regression equation is established: Where x and y are the resistance and symbol to be solved; Analyze the signs of x, y and Formula 1 and Formula 2: When x is a negative number and y is a positive number, the resistance and sign of the solution satisfy the form of the resistance and sign in Formula 1, indicating that LMU1 and LMU2 are in a bifurcated relationship; when x is a positive number and y is a positive number, the resistance and sign of the solution satisfy the form of the resistance and sign in Formula 2, indicating that LMU1 and LMU2 are in an up-down relationship; Based on the order of LMU load from high to low, the LMU to be compared is compared with the LMU in the existing LMU-LMU topology structure, and the LMU-LMU relationship model based on Kirchhoff's law is established one by one. Based on the results returned by the model, the real position of the LMU to be compared in the LMU-LMU structure is obtained; Based on Kirchhoff's law, an LMU-household meter identification relationship model is established: when the household meter M is under any LMU, according to Kirchhoff's law, the LMU voltage is set to U3, the household meter voltage and current are U4 and I4 respectively, and the resistance between the household meter and the LMU is R, then there is a relationship: U4+I4×R=U3, that is, U3–U4=I4×R. For a household meter M and a certain LMU meter, based on the LMU high-frequency voltage U'3, the household meter high-frequency voltage and current U′4 and I′4, a regression equation is established: Based on the least squares method, find the best estimate of the unknown number z And the goodness of fit S of the regression equation, where the solution is is the resistance between LMU and household meter, and the goodness of fit S is used to evaluate the fitting effect of LMU and current household meter data on the model formula U3–U4=I4×R. The goodness of fit S is calculated as follows: Among them, u1 and u2 are the average values ​​of the voltage curves of the LMU meter and the household meter, respectively. 1i 、u 2i are the values ​​on the voltage curve of the i-th LMU meter and the household meter, I 2i is the current value of the ith household meter; when When the value is within the range of 0-1 ohm and the goodness of fit S>0.9, it means that the current LMU and household meter data have a good explanation effect on the model formula, that is, the actual position of the current household meter is under the current LMU; when The value is negative or If the value is greater than 1 ohm or the goodness of fit S is less than 0.3, it means that the current LMU and household meter data have a poor interpretation effect on the model formula, that is, the actual location of the current household meter is not under the current LMU; Based on the identified complete LMU-LMU structure, for each household meter, an LMU-household meter identification model based on Kirchhoff's law is established with all LMUs, and finally the LMU to which the current household meter belongs is determined.

2. The method for identifying a substation topology based on Kirchhoff's law according to claim 1, characterized in that: The data includes collecting the voltage and current data of all the electric energy meters in the substation area; after acquiring the data, removing the empty data so that the current and voltage data of the LMU and each electric energy meter do not contain empty points, deleting all the electric energy meter voltage and current empty value data and abnormal data, so that the voltage and current data of each electric energy meter are aligned according to the time series.

3. A method for identifying a substation topology based on Kirchhoff's law as claimed in claim 2, characterized in that: The LMU-LMU identification relationship model includes: for any two LMUs, the position relationship based on the topology is divided into bifurcation type and up-down type, and an LMU-LMU identification relationship model based on Kirchhoff's law is established. For any two LMU1, LMU2 and high-frequency voltage and current data, a regression equation is established and the solved resistance and symbol are analyzed to determine the position relationship of any two LMUs.

4. A method for identifying a substation topology based on Kirchhoff's law as claimed in claim 3, characterized in that: The real position includes, based on the LMU-LMU identification relationship model, initializing the LMU-LMU structure to be empty, arranging the LMU meters from large to small based on the average value of the high-frequency current of the LMU meters, and placing the LMUs in the arranged list one by one. i By comparing with the LMU in the existing LMU-LMU structure, the LMU-LMU identification relationship model is established to obtain the real position of the LMU-LMU topology.

5. A method for identifying a substation topology based on Kirchhoff's law as claimed in claim 4, characterized in that: The method of determining the LMU to which the current household meter belongs includes generating an LMU-LMU structure based on the LMU-household meter identification relationship model and the real position identification process of the LMU-LMU topology, for all household meter sets {M1, M2, M3, M i ,…,M m Each user table M in i High frequency voltage and current data U′ mi , I′ mi , respectively, with each LMU in the LMU-LMU structure obtained in the real position identification process of the LMU-LMU topology i (i=1,2,3,…) high frequency voltage data U' i , establish the LMU-household table identification relationship model and solve it, and get the household table M and all LMU i Estimated resistance Z of (i=1,2,3,…) i and goodness of fit S, excluding unreasonable estimated resistance Z i , when Z i <0 or Z i >1, the remaining LMU candidate set is [LMU i1 ,LMU i2 ,LMU i3 ], and select the LMU with the highest goodness of fit S i , which is the current household table M i The LMU branch to which it belongs.

6. A system using a method for identifying a substation topology based on Kirchhoff's law as claimed in any one of claims 1 to 5, characterized in that: It includes a data preprocessing module, an LMU-LMU identification module, an LMU-LMU location identification module, an LMU-household meter identification and establishment module, and a household meter determination module; The data preprocessing module collects the voltage and current data of all electric energy meters in the substation area; removes empty data and abnormal data to ensure that the current and voltage data of the LMU and each electric energy meter are complete and aligned according to the time series; performs multipath interference optimization and constructs a network current distribution model; The LMU-LMU identification module, based on Kirchhoff's law, classifies the positional relationship between any two LMUs into bifurcated type and up-down type, and establishes a corresponding mathematical model; The LMU-LMU position identification module initializes the LMU-LMU structure to be empty, sorts the LMU meters according to the average value of the high-frequency current, compares them one by one with the LMUs in the existing LMU-LMU structure, and determines the real position of each LMU in the LMU-LMU structure; The LMU-household meter identification establishment module establishes an LMU-household meter identification model for each household meter and a certain LMU based on Kirchhoff's law, and solves the resistance and goodness of fit between the LMU and the household meter through a regression equation; The household meter determination module compares the high-frequency voltage and current data of each household meter with each LMU in the LMU-LMU structure based on the LMU-household meter identification relationship model and the actual position of the LMU-LMU topology to determine the LMU to which the household meter belongs.

7. The system of the method for identifying the substation topology based on Kirchhoff's law as claimed in claim 6, characterized in that: The data preprocessing module includes: the data preprocessing module collects voltage and current data of all LMUs, i.e., line monitoring units, and household meters, i.e., residential electric energy meters, from the low-voltage rural power grid in the substation area; after the data collection is completed, the data preprocessing module cleans the data, including removing empty data and abnormal data, and aligning the data in time series to ensure that the timestamp of each data point is consistent; The data preprocessing module performs multipath interference optimization and builds a network current distribution model; The output result of the data preprocessing module is input into the LMU-LMU identification module; the LMU-LMU identification module receives the preprocessed data, and classifies the topological position relationship between any two LMUs according to Kirchhoff's law. For each topological relationship, the module establishes a mathematical model, and after the model is established, the model is passed to the LMU-LMU position identification module; after the LMU-LMU position identification module determines the position of the LMU, the module outputs a complete LMU-LMU topological structure, which is input into the LMU-household meter identification module for use; the LMU-household meter identification module receives the LMU-LMU topological structure and household meter data, and establishes an identification model for each household meter and LMU based on Kirchhoff's law. The module outputs the resistance estimation value and goodness of fit between each household meter and LMU, and passes it to the household meter determination module; The household meter determination module receives the result of the LMU-household meter identification module, outputs the LMU to which each household meter belongs, and completes the identification of the entire substation topology.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the processor implements the steps of a method for identifying a substation topology based on Kirchhoff's law according to any one of claims 1 to 5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a method for identifying a substation topology based on Kirchhoff's law according to any one of claims 1 to 5 are implemented.

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