Power distribution network protection method and device, electronic equipment and computer program product

Abstract

The application discloses a power distribution network protection method and device, electronic equipment and computer program product. It relates to the technical field of power distribution network protection. The method comprises the following steps: acquiring node voltages of H target node partitions of a power distribution line; dividing multiple domains according to the H target node partitions; constructing node voltage fault components of the domains based on the node voltages of each domain; determining node impedance matrices of each domain; determining node current fault components to be solved according to the node voltage fault components and the node impedance matrices; calculating the node current fault components to be solved based on an orthogonal matching pursuit algorithm, and solving the node current fault components of each domain; and controlling nodes at both ends of a fault area to be disconnected according to the relationship between each node current in the node current fault components of each domain and a node current fault threshold. The application solves the problem that the traditional power distribution network protection technology takes a long time to locate a fault point and has low accuracy, thereby affecting the safety of the power distribution network.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power distribution network protection, in particular to a power distribution network protection method and device, an electronic device and a computer program product. BACKGROUND

[0002] In recent years, a large number of distributed photovoltaic devices are connected to the power distribution network. When a high proportion of photovoltaic devices are connected to the power distribution network system, once a fault occurs, the current generated by the fault is in a multi-point and scattered state, which changes the spatial distribution rule of the fault characteristics of the power distribution system. The traditional protection method has the possibility of incorrect fault area judgment or failure to trigger the fault point positioning, and the fault clearance time is relatively long, which causes the power distribution equipment to bear the short-circuit current for a long time, threatening the safe operation of the power distribution network system.

[0003] At present, there is no effective solution to the problem of long time consumption and low accuracy of the traditional power distribution network protection technology in positioning the fault point, which affects the safety of the power distribution network. SUMMARY

[0004] The present application provides a power distribution network protection method and device, an electronic device and a computer program product to solve the problem of long time consumption and low accuracy of the traditional power distribution network protection technology in positioning the fault point, which affects the safety of the power distribution network.

[0005] According to one aspect of the present application, a power distribution network protection method is provided, which is applied to a power distribution line in a power distribution network system. The method comprises: obtaining node voltages of H target node partitions of the power distribution line, dividing a plurality of domains according to the H target node partitions, and constructing a node voltage fault component of each domain based on the node voltages of the domain, wherein each node partition is obtained through a voltage transformer, the number of voltage transformers is less than the number of nodes in the node partition, each domain includes a plurality of target node partitions, each target node partition includes at least two nodes, and H is a positive integer; determining a node impedance matrix of each domain according to the impedance size of the power distribution line and the impedance size of the transformer, wherein the transformer is arranged between the power source and the power distribution line; for each domain, determining a node current fault component to be solved of the domain according to the node voltage fault component of the domain and the node impedance matrix of the domain, wherein the node current fault component includes the currents of a plurality of nodes; calculating the node current fault component to be solved of each domain based on the orthogonal matching pursuit algorithm, and solving the node current fault component of each domain; in each domain, determining a fault area according to the relationship between each node current in the node current fault component of the domain and the node current fault threshold, and controlling the nodes at both ends of the fault area to be disconnected.

[0006] Optionally, before the target node voltages of the H target node partitions of the power distribution line are acquired, the method further comprises: determining a topology of the power distribution line, wherein the power distribution line comprises G initial node partitions, G is a positive integer, and G is less than H; for each initial node partition, calculating a voltage difference of the initial node partition according to a head-end node voltage and an end node voltage of the initial node partition; comparing the voltage differences of the G initial node partitions with a voltage difference threshold value respectively to obtain H1 first initial node partitions and H2 second initial node partitions, wherein the voltage differences of the H1 first initial node partitions are greater than the voltage difference threshold value, the voltage differences of the H2 first initial node partitions are less than or equal to the voltage difference threshold value, and H1+H2=G; splitting each of the H1 first initial node partitions to obtain H3 first target node partitions, and the H target node partitions are composed of the H3 first target node partitions and the H2 first initial node partitions, and H2+H3=H.

[0007] Optionally, according to the impedance size of the power distribution line and the impedance size of the transformer, the method for determining the node impedance matrix of each domain comprises: determining an initial node impedance matrix, wherein the elements in the initial node impedance matrix represent the relationship between the complex impedances of two nodes; for each node connected to the distributed photovoltaic power supply, determining an additional impedance of the distributed photovoltaic power supply according to the output current of the distributed photovoltaic power supply, adding the initial impedance of the node and the node impedance of the additional impedance to obtain a target impedance; for each node not connected to the distributed photovoltaic power supply, determining the initial impedance of the node as the target impedance; and determining the node impedance matrix of each domain by the target impedances of all nodes connected to the distributed photovoltaic power supply and the target impedances of all nodes not connected to the distributed photovoltaic power supply.

[0008] Optionally, for each domain, according to the node voltage fault component of the domain and the node impedance matrix of the domain, the method for determining the node current fault component to be solved of the domain comprises: for each domain, calculating the current value of each node of the domain according to the node voltage fault component of the domain and the target node impedance matrix of the domain; and constructing the node current fault component to be solved of the domain according to the current values of all nodes of the domain.

[0009] Optionally, for each node connected to the distributed photovoltaic power supply, determining the additional impedance of the distributed photovoltaic power supply according to the output current of the distributed photovoltaic power supply comprises: measuring the voltage of the node connected to the distributed photovoltaic power supply, and determining the measured voltage as a distributed photovoltaic voltage fault component phasor; measuring the current of the node connected to the distributed photovoltaic power supply, and determining the measured current as a distributed photovoltaic current fault component phasor; and calculating the distributed photovoltaic impedance of the node connected to the distributed photovoltaic power supply by the distributed photovoltaic voltage fault component phasor and the distributed photovoltaic current fault component phasor to obtain the additional impedance.

[0010] Optionally, the node current fault component of each domain is calculated based on an orthogonal matching pursuit algorithm, and the node current fault component of each domain is solved by: obtaining an inverse matrix of a node impedance matrix of each domain, performing inner product calculation on each column of the inverse matrix and an initialized residual to obtain a plurality of inner product values, determining a column where a maximum inner product value in the plurality of inner product values is located, and calculating a difference between the node voltage fault component and an orthogonal projection matrix of the column where the maximum inner product value is located to obtain a residual of a first iteration calculation, wherein the initialized residual represents the node voltage fault component of the domain; removing the column corresponding to the maximum inner product value in the last iteration calculation from the inverse matrix to obtain an updated inverse matrix, performing inner product calculation on each column of the updated inverse matrix and the residual of the first iteration calculation to obtain an updated plurality of inner product values, determining an updated column where an updated maximum inner product value in the updated plurality of inner product values is located, and calculating a difference between the node voltage fault component and an orthogonal projection matrix of the updated column where the updated maximum inner product value is located to obtain a residual of a second iteration calculation; continuously performing iteration calculation until a termination condition of the iteration calculation is reached, constructing a one-dimensional vector based on a plurality of maximum inner product values obtained through a plurality of iteration calculations, and determining the node current fault component of each domain according to the one-dimensional vector, wherein each maximum inner product value represents each element in the one-dimensional vector.

[0011] Optionally, in each domain, the fault area is determined according to the relationship between each node current in the node current fault component of the domain and the node current fault threshold, and the nodes at both ends of the fault area are controlled to be disconnected by: determining the maximum value and the second maximum value of the node currents of the a nodes in the target node partition of each domain through the node current fault component of each domain; when the maximum value and the second maximum value are both greater than the node current fault threshold, determining that the node corresponding to the maximum value and the node corresponding to the second maximum value are on both sides of the fault area, and controlling the nodes at both ends of the fault area to be disconnected, wherein the node corresponding to the maximum value and the node corresponding to the second maximum value are adjacent two nodes.

[0012] According to another aspect of the present application, a protection device of a power distribution network is provided. The device comprises: a constructing unit configured to obtain node voltages of H target node partitions of a power distribution line, divide a plurality of domains according to the H target node partitions, and construct node voltage fault components of the domains based on the node voltages of each domain, wherein each node partition is obtained by a voltage transformer, the number of voltage transformers is less than the number of nodes in the node partition, each domain comprises a plurality of target node partitions, at least two nodes are included in each target node partition, H is a positive integer; a first determining unit configured to determine a node impedance matrix of each domain according to an impedance size of the power distribution line and an impedance size of a transformer, wherein the transformer is arranged between a power supply and the power distribution line; a second determining unit configured to determine, for each domain, a node current fault component to be solved of the domain according to the node voltage fault components of the domain and the node impedance matrix of the domain, wherein the node current fault component contains currents of a plurality of nodes; a calculating unit configured to calculate the node current fault component to be solved of each domain based on an orthogonal matching pursuit algorithm, and solve the node current fault component of each domain; and a control unit configured to determine, in each domain, a fault area according to a relationship between each node current in the node current fault component of the domain and a node current fault threshold, and control nodes at two ends of the fault area to be disconnected.

[0013] According to another aspect of the present application, an electronic device is also provided, comprising a processor and a memory; the memory stores computer readable instructions, and the processor is configured to execute the computer readable instructions, wherein the computer readable instructions perform a protection method of a power distribution network when executed.

[0014] According to another aspect of the present application, a computer program product is provided, comprising a non-volatile computer readable storage medium, the non-volatile computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement any of the above-mentioned protection methods of a power distribution network.

[0015] By the present application, the following steps are adopted: acquiring node voltages of H target node partitions of a power distribution line, dividing multiple domains according to the H target node partitions, constructing node voltage fault components of the domains based on the node voltages of each domain, wherein each node partition is acquired by a voltage transformer, the number of voltage transformers is less than the number of nodes in the node partition, each domain includes multiple target node partitions, the target node partition includes at least two nodes, H is a positive integer; determining a node impedance matrix of each domain according to the impedance size of the power distribution line and the impedance size of the transformer, wherein the transformer is arranged between the power supply and the power distribution line; for each domain, determining a node current fault component to be solved of the domain according to the node voltage fault component of the domain and the node impedance matrix of the domain, wherein the node current fault component contains the currents of multiple nodes; calculating the node current fault component to be solved of each domain based on the orthogonal matching pursuit algorithm, and solving the node current fault component of each domain; in each domain, determining a fault area according to the relationship between each node current in the node current fault component of the domain and the node current fault threshold, and controlling the nodes at both ends of the fault area to be disconnected, which solves the problem that the traditional protection technology of the power distribution network has long time consumption and low accuracy in locating the fault point, and affects the safety of the power distribution network. The fault area is determined by a small number of installed voltage transformer measuring points and the orthogonal matching pursuit algorithm, thereby achieving the effect of accurately and quickly locating the fault point. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of this application illustrated in the drawings, and their description, are presented to add generic scope to this application. In the drawings:

[0017] Figure 1 is a flowchart of a protection method of a power distribution network according to an embodiment of the present application;

[0018] Figure 2 is a flowchart of a node current fault component calculation method based on an orthogonal matching pursuit algorithm according to an embodiment of the present application;

[0019] Figure 3 is an optional schematic diagram of a power distribution network according to an embodiment of the present application;

[0020] Figure 4 is a schematic diagram of a positioning protection result according to an embodiment of the present application;

[0021] Figure 5 is a schematic diagram of a protection device of a power distribution network according to an embodiment of the present application;

[0022] Figure 6 is a schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] It should be noted that the embodiments and features of the present application can be combined with each other in the case of no conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0024] In order for those skilled in the technical field to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0025] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0026] It should be noted that the relevant information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for display, analyzed data, etc.) involved in the present disclosure are all information and data authorized by the user or authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of relevant data comply with relevant laws, regulations and standards in relevant regions, necessary security measures are taken, do not violate public order and good customs, and provide corresponding operation portal for users to choose to authorize use or refuse to use.

[0027] According to the embodiments of the present application, a power distribution network protection method is provided, which is applied to a power distribution line in a power distribution network system.

[0028] Figure 1 is a flowchart of the power distribution network protection method according to the embodiments of the present application. As shown in Figure 1 the method comprises the following steps:

[0029] In step S101, node voltages of H target node partitions of the power distribution line are acquired, multiple domains are divided according to the H target node partitions, and node voltage fault components of the domains are constructed based on the node voltages of each domain, wherein each node partition is acquired by a voltage transformer, the number of voltage transformers is less than the number of nodes in the node partition, each domain includes multiple target node partitions, at least two nodes are included in each target node partition, H is a positive integer.

[0030] Before acquiring the target node voltages of the H target node partitions of the power distribution line, the method further includes: determining a topology structure of the power distribution line, wherein the power distribution line includes G initial node partitions, G is a positive integer, and G is less than H; for each initial node partition, a voltage difference of the initial node partition is calculated according to a head node voltage and an end node voltage of the initial node partition; the voltage difference of the G initial node partitions and a voltage difference threshold value are compared respectively to obtain H1 first initial node partitions and H2 second initial node partitions, wherein the voltage difference of the H1 first initial node partitions is greater than the voltage difference threshold value, the voltage difference of the H2 first initial node partitions is less than or equal to the voltage difference threshold value, and H1+H2=G; each of the H1 first initial node partitions is split to obtain H3 first target node partitions, the H3 first target node partitions and the H2 first initial node partitions constitute the H target node partitions, and H2+H3=H.

[0031] It should be noted that the node voltage represents the voltage of the node in the power distribution line. The node voltage fault component is a one-dimensional vector, and each element in the vector represents the node voltage of each target node partition. The node partition and the domain are both divided for subsequent construction of the node current fault component. The relationship between the power distribution line, the domain, the node partition and the node is: there are multiple domains in the power distribution line, there are multiple node partitions in each domain, and there are multiple nodes in each node partition, and the node voltage of each node partition is represented as a set of three-phase voltage data, which is a trigonometric function waveform.

[0032] The topology structure of the power distribution line refers to the connection mode and layout of the nodes and branches in the power distribution line. Any power distribution line can be equivalent to a power distribution network with multiple parent nodes and multiple branches according to its topology structure, multiple initial node partitions are divided according to the number of branches, each initial node partition has multiple nodes, and each node partition is provided with a voltage transformer, wherein the branch can be long, and therefore the node partition needs to be further divided according to the voltage difference between the head node voltage of the branch and the end node voltage of the branch. The formula of the voltage difference is as formula (1):

[0033] ΔU b =U i -U j (1)

[0034] In the formula, U i represents the voltage of the head node of a branch j represents the voltage of the end node of the branch, ΔU b represents the voltage difference between the head node voltage and the end node voltage of the branch.

[0035] According to the comparison result of the voltage difference and the voltage difference threshold T, a first initial node partition whose voltage difference is greater than the voltage difference threshold and a second initial node partition whose voltage difference is less than the voltage difference threshold can be obtained. When the voltage difference is greater than the voltage difference threshold, the first initial node partition is re-divided so that the new first initial node partition (corresponding to the above-mentioned first target node partition) satisfies formula (2):

[0036] ΔU b <T (2)

[0037] In the formula, T represents the voltage difference threshold.

[0038] Based on all the new first initial node partitions and the second initial node partitions, the target node partitions are obtained, and the multiple domains are re-divided according to the target node partitions. Each domain is composed of multiple target node partitions, and each target node partition has a node voltage fault component. According to the node voltage fault component of each target node partition, a domain node voltage fault component is formed. For example, the target nodes of a domain are N, and the node voltage fault component of each target node partition is The formula (3) can be used to represent it, is composed of the voltage fault component of each node in the N nodes, where N is a positive integer.

[0039]

[0040] For example, the distribution line is divided into 6 domains, and each domain has its own domain node voltage fault component. Therefore, the distribution line has a total of 6 domain node voltage fault components.

[0041] In step S102, the node impedance matrix of each domain is determined according to the impedance size of the distribution line and the impedance size of the transformer. The transformer is arranged between the power supply and the distribution line.

[0042] The impedance of a power distribution line refers to the sum of the resistance and reactance of multiple branches in a power system, the resistance is determined according to the material characteristics of the line itself, and the reactance is mainly derived from the inductive reactance and capacitive reactance of the line. The impedance of a transformer refers to the electromagnetic resistance between the input end and the output end of the transformer. The node impedance matrix is used to describe the reactance characteristics between nodes in the power distribution line of the power system. The dimension of the node impedance matrix is determined by the number of nodes in the power distribution line, for example, a domain in the power distribution line has N nodes, so the dimension of the node impedance matrix of the domain is N*N. The elements of the node impedance matrix are essentially elements composed of real part resistance and imaginary part reactance.

[0043] In step S103, for each domain, the node current fault component to be solved in the domain is determined according to the node voltage fault component of the domain and the node impedance matrix of the domain, wherein the node current fault component contains the currents of multiple nodes.

[0044] In this step, the node current fault component to be solved is an unknown quantity represented by the node voltage fault component of the domain and the node impedance matrix of the domain. When a fault occurs, it is difficult to predict the fault condition and location in advance, and it is difficult to obtain the network model after the fault of the power distribution line. Therefore, the current displacement theory is adopted, the fault current of the fault injection point is equivalent to two virtual current components, and then the two virtual current components are injected into the nodes at both ends of the fault section, so as to represent the node current fault component after displacement by the virtual current component. For example, if a domain in the power distribution line has N nodes, the node current fault component is an N*1-dimensional vector, which is essentially a column vector with N rows. It can be represented by formula (4). Each row in the vector is the node current of each node. F represents the injection point of the fault current, which is equivalent to two virtual current components injected into nodes l and m at both ends of the fault section, so as to ensure that the network topology remains unchanged before and after the fault occurs. Wherein, the two virtual current components are denoted as and In each domain, the relationship between the node current fault component, the node voltage fault component and the node impedance matrix is obtained according to Ohm's law, which is specifically represented by formula (5).

[0045]

[0046]

[0047] In the formula, is the node current fault component in each domain, is the fault current component provided by the distributed photovoltaic (the subscript i=1, 2, …, k represents the photovoltaic power number), is the node admittance matrix in each domain, This refers to the node voltage fault component within each domain, which is composed of the node voltage of each node in the domain. However, because the actual number of voltage transformers installed is limited, they are only installed in sections within each node, making it impossible to measure the node voltage of every domain. For example, if there are N nodes in each domain, but only M measurement points, where M is much smaller than N, then... From The rows corresponding to M measurement points are obtained by extracting them from the data. It is an M*1 dimensional vector. This is the nodal impedance matrix in each domain. Wherein, and The node impedance matrices are inverses of each other.

[0048] Step S104: Calculate the node current fault components to be solved for each domain based on the orthogonal matching pursuit algorithm, and obtain the node current fault components for each domain.

[0049] The Orthogonal Matching Pursuit algorithm is used to solve for the node current fault component. By calculating the residual value in each iteration, the maximum value of the inner product in each iteration gets closer and closer to the value of the corresponding column of the node voltage fault component. At the same time, the influence of the previous calculation is eliminated in each iteration. Finally, a node current fault component is constructed by the maximum value of the inner product obtained by multiple iterations, thus completing the solution process for the node current fault component.

[0050] Step S105: In each domain, based on the relationship between the node currents and the node current fault thresholds in the node current fault components of the domain, determine the fault region and control the nodes at both ends of the fault region to disconnect.

[0051] Each node current is represented as an element in the node current fault component. The node current fault threshold is a preset fault threshold, which refers to the critical value at which a node current exceeding a certain preset value may trigger a fault in the distribution line. A fault area is a segment consisting of two nodes. By identifying the locations of the two nodes with currents exceeding the node current fault threshold, the fault area can be determined. By controlling the disconnection of the nodes at both ends of the fault area, timely protection of the fault area can be achieved.

[0052] The method for protecting the power distribution network provided in the embodiments of the present application comprises the following steps: obtaining node voltages of H target node partitions of a power distribution line; dividing a plurality of domains according to the H target node partitions; constructing node voltage fault components of the domains based on the node voltages of the domains, wherein each node partition is obtained by a voltage transformer, the number of the voltage transformers is less than the number of nodes in the node partition, each domain comprises a plurality of target node partitions, at least two nodes are included in each target node partition, and H is a positive integer; determining a node impedance matrix of each domain according to the impedance of the power distribution line and the impedance of a transformer, wherein the transformer is arranged between a power source and the power distribution line; for each domain, determining a node current fault component to be solved of the domain according to the node voltage fault components of the domain and the node impedance matrix of the domain, wherein the node current fault component comprises currents of a plurality of nodes; calculating the node current fault component to be solved of each domain based on an orthogonal matching pursuit algorithm, and solving the node current fault component of each domain; in each domain, determining a fault area according to the relationship between each node current in the node current fault component of each domain and a node current fault threshold, and disconnecting nodes at both ends of the fault area, thereby solving the problem that the traditional protection technology of the power distribution network has a long time for locating a fault point and low accuracy, which affects the safety of the power distribution network. The fault point is determined by a small number of measuring points of the voltage transformers and the orthogonal matching pursuit algorithm, thereby achieving the effect of accurately and rapidly locating the fault point.

[0053] In order to determine the node current fault component by using the orthogonal matching pursuit algorithm, the node impedance matrix of each domain needs to be calculated. Alternatively, in the method for protecting the power distribution network provided in the embodiments of the present application, the method for determining the node impedance matrix of each domain according to the impedance of the power distribution line and the impedance of the transformer comprises the following steps: determining an initial node impedance matrix, wherein the elements in the initial node impedance matrix represent the relationship between the complex impedances of two nodes; for each node connected to a distributed photovoltaic power source, determining an additional impedance of the distributed photovoltaic power source according to the output current of the distributed photovoltaic power source, adding the initial impedance of the node and the node impedance of the additional impedance to obtain a target impedance; for each node not connected to the distributed photovoltaic power source, determining the initial impedance of the node as the target impedance; and determining the node impedance matrix of each domain from the target impedances of all nodes connected to the distributed photovoltaic power source and the target impedances of all nodes not connected to the distributed photovoltaic power source.

[0054] The nodes in each domain are divided into nodes connected to the distributed photovoltaic power supply and nodes not connected to the distributed photovoltaic power supply. Determining the node impedance matrix of each domain first needs to construct an initial node impedance matrix, and secondly, the influence of the distributed photovoltaic power supply on the node current fault component is considered. For the nodes connected to the distributed photovoltaic power supply, the distributed photovoltaic power supply will make the node current fault component not meet the sparse condition, that is, except for the node current of the two ends of the fault area being not 0, the node current of the remaining nodes is 0, and the requirement of the orthogonal matching pursuit algorithm is that the matrix to be solved must be sparse, so it is necessary to convert the current of the node connected to the distributed photovoltaic power supply into additional impedance. For the nodes not connected to the distributed photovoltaic power supply, the target impedance is directly determined by the initial impedance. Finally, by synthesizing the target impedance of all nodes connected to the photovoltaic power supply and the target impedance of all nodes not connected to the photovoltaic power supply, the node impedance matrix of each domain can be determined by formula (6).

[0055]

[0056] In the formula: is the node impedance matrix of each domain, and each element in the matrix represents the impedance of each node.

[0057] Through the embodiment, the target impedance of all nodes connected to the photovoltaic power supply and the target impedance of all nodes not connected to the photovoltaic power supply are determined to obtain the node impedance matrix of each domain, so that the precondition of making the node current fault component of each domain meet the orthogonal matching pursuit algorithm is achieved.

[0058] The node current fault component to be solved is determined through the relationship between the node voltage fault component of each domain and the node impedance matrix of each domain. Optionally, in the power distribution network protection method provided in the embodiment, for each domain, the node current fault component to be solved of the domain is determined according to the node voltage fault component of the domain and the node impedance matrix of the domain, which includes: for each domain, the current value of each node of the domain is calculated according to the node voltage fault component of the domain and the target node impedance matrix of the domain; and the node current fault component to be solved of each domain is constructed according to the current values of all nodes of the domain.

[0059] Firstly, the node voltage fault component of each domain needs to be determined, which describes the voltage of each node when a fault occurs. At the same time, in order to obtain the node current fault component of the domain, the target node impedance matrix of the domain also needs to be determined, which contains the impedance characteristics of the electrical connection lines between nodes in the domain. By combining the node voltage fault component and the target node impedance matrix, the current value of each node in each domain can be calculated. The calculation method is based on Ohm's law to obtain the node current by using the relationship between the voltage fault component and the impedance matrix. After obtaining the current value of all nodes, the current value of each node is taken as each element in a one-dimensional vector, thereby constructing the node current fault component of each domain.

[0060] Through the embodiment, the node current fault component to be solved of the domain is obtained according to the node voltage fault component of each domain and the target node impedance matrix of each domain, thereby achieving the effect of laying a foundation for subsequent application of the orthogonal matching tracking algorithm.

[0061] In order to eliminate the influence of the node-to-node impedance matrix of the distributed photovoltaic power supply, optionally, in the power distribution network protection method provided in the embodiments of the present application, for each node accessing the distributed photovoltaic power supply, the additional impedance of the distributed photovoltaic power supply is determined according to the output current of the distributed photovoltaic power supply, including: measuring the voltage of the node accessing the distributed photovoltaic power supply, and determining the measured voltage as a distributed photovoltaic voltage fault component phasor; measuring the current of the node accessing the distributed photovoltaic power supply, and determining the measured current as a distributed photovoltaic current fault component phasor; calculating the distributed photovoltaic impedance of the node accessing the distributed photovoltaic power supply through the distributed photovoltaic voltage fault component phasor and the distributed photovoltaic current fault component phasor to obtain the additional impedance.

[0062] In the distribution line, the node accessing the distributed photovoltaic power supply needs to specially consider the influence of the characteristics of the photovoltaic power supply on the system. Therefore, the additional impedance of the distributed photovoltaic power supply needs to be determined, and this process involves several key steps. First, the voltage of the node accessing the distributed photovoltaic power supply is measured, and this measured value is defined as the phasor of the distributed photovoltaic voltage fault component, which reflects the change of the voltage under fault condition. Then, the current of the same node is measured, and this current value is defined as the phasor of the distributed photovoltaic current fault component, which represents the change of the current under fault condition. With the phasors of the two fault components, the impedance of the distributed photovoltaic power supply accessing the node can be calculated according to formula (7). The calculated impedance value is the additional impedance, which reflects the influence of the distributed photovoltaic power supply on the node impedance of the distribution line.

[0063]

[0064] wherein, is the equivalent impedance of the distributed photovoltaic power supply, is a distributed photovoltaic voltage fault component phasor, is a distributed photovoltaic current fault component phasor.

[0065] Through the embodiment, by measuring the voltage of the node accessing the distributed photovoltaic power supply and measuring the current of the node accessing the distributed photovoltaic power supply, the amount of current output by the distributed photovoltaic power supply is converted into additional impedance in the node impedance matrix, and the effect of eliminating the influence of the distributed photovoltaic power supply on the node current fault component to be solved in the orthogonal matching pursuit equation is achieved.

[0066] Figure 2 is a flowchart of a node current fault component calculation method based on an orthogonal matching pursuit algorithm according to an embodiment of the present application. As shown in Figure 2 , the node current fault component to be solved in each domain is calculated based on the orthogonal matching pursuit algorithm, and the node current fault component in each domain is solved, including the following steps:

[0067] Step S201, obtaining the inverse matrix of the node impedance matrix of each domain, calculating the inner product of each column of the inverse matrix and the initialization residual to obtain a plurality of inner product values, determining the column where the maximum inner product value in the plurality of inner product values is located, and calculating the difference between the node voltage fault component and the orthogonal projection matrix of the column where the maximum inner product value is located to obtain the residual of the first iteration calculation, wherein the initialization residual represents the node voltage fault component of the domain.

[0068] Wherein, the inner product of each column of the inverse matrix and the initialization residual is calculated to obtain a plurality of inner product values, the column where the maximum inner product value in the plurality of inner product values is obtained through formula (8):

[0069]

[0070] In the formula, , represents the transpose of the i-th column of Ф, r k represents the residual, the initialization r0 is the node voltage fault component of the domain, and argmax represents the maximum value of the product. and r k .

[0071] The orthogonal projection matrix of the column where the maximum inner product value is located can be obtained through formula (9), and the residual of the first iteration calculation can be obtained through formula (10):

[0072]

[0073] r k =(I-P k )y (10)

[0074] In the formula, Ф S represents the matrix composed of the i-th column of the extracted vector, denotes the transpose of S , P k is an orthogonal projection matrix, P0=0 is initialized, and I is an identity matrix.

[0075] In the formula, y=Φθ+e, y is an observation vector of M*1, Φ is a perception matrix of M*N, θ is a sparse vector to be reconstructed of N*1, and e is a Gaussian white noise of N*1.

[0076] In step S202, the column corresponding to the maximum inner product value in the last iteration calculation is removed from the inverse matrix to obtain an updated inverse matrix, and the inner product of each column of the updated inverse matrix and the residual in the first iteration calculation is calculated to obtain an updated plurality of inner product values, the column of the updated maximum inner product value in the updated plurality of inner product values is determined, and the difference between the node voltage fault component and the orthogonal projection matrix of the column of the updated maximum inner product value is calculated to obtain the residual in the second iteration calculation.

[0077] In step S203, the iteration calculation is continuously performed until the termination condition of the iteration calculation is reached, a one-dimensional vector is constructed based on a plurality of maximum inner product values in a plurality of iteration calculations, and the node current fault component of each domain is determined according to the one-dimensional vector, wherein each maximum inner product value represents each element in the one-dimensional vector.

[0078] Wherein, the node current fault component of each domain can be obtained by formula (11):

[0079]

[0080] In the formula, θ S represents the matrix composed of i , θ i represents the i-th element of θ, and θ is the node current fault component of each domain to be solved.

[0081] Through the embodiment, the orthogonal matching pursuit algorithm is used to calculate the node current fault component of each domain, so that the effect of accurately determining the node current of each domain is achieved.

[0082] Optionally, in the power distribution network protection method provided in this application embodiment, in each domain, determining the fault area based on the relationship between each node current in the node current fault component of the domain and the node current fault threshold, and controlling the nodes at both ends of the fault area to disconnect includes: determining the maximum and second largest values ​​of the node currents of a nodes in the target node partition of each domain through the node current fault component of each domain; when both the maximum and second largest values ​​are greater than the node current fault threshold, determining the node corresponding to the maximum value and the node corresponding to the second largest value as the two sides of the fault area, and controlling the nodes at both ends of the fault area to disconnect, wherein the node corresponding to the maximum value and the node corresponding to the second largest value are two adjacent nodes.

[0083] Each element in each row of the node current fault component in each domain represents the current value of each node in that domain. The current values ​​of multiple nodes are compared with the node current fault threshold. Only when the maximum and second largest values ​​of the node current are both greater than the node fault threshold can the fault area be determined, as shown in formula (12):

[0084]

[0085] In the formula Indicates the calculated The magnitude of the injected current fault component at the nth node in the matrix. Indicates the calculated The magnitude of the injected current fault component at the (n+1)th node in the matrix, where ε is the node current fault threshold. The comparison is made to eliminate the influence of calculation errors. For example, if both the maximum and second-largest values ​​are 0.0001, and the node current fault threshold is 0.2, then the maximum and second-largest values ​​do not both exceed the node fault threshold. Therefore, it can be determined that the node has not experienced a fault; the error is merely due to calculation errors.

[0086] In this embodiment, by comparing the magnitudes of all elements in the node current fault component with the node current fault threshold, the area where the fault occurred can be obtained, thereby achieving the effect of accurately locating the fault point of the power distribution line.

[0087] Figure 3 This is a schematic diagram of an optional power distribution network according to an embodiment of this application, such as... Figure 3 As shown, photovoltaic power sources are installed at nodes 40 and 44 to simulate the impact of distributed energy. A ±5% error limit is set for the line parameters to simulate the changes in grid parameters under actual operation with environmental variations. Then, seven fault branches are randomly selected: 17-18, 31-32, 38-39, 42-43, 44-45, 48-49, and 59-60. The distribution network location protection results are analyzed under different fault types, and compared with existing fault location protection methods to verify the effectiveness of the proposed algorithm.

[0088] The embodiment of the application applies a protection method of a power distribution network based on an orthogonal matching pursuit algorithm, divides the network into 6 domains, and performs positioning calculation on each domain respectively, and selects the measuring points 4, 10, 28, 36 and 53 at the outlets of the No. 3 and No. 9 buses as the node domain boundary. Taking the domain 36-46 as an example, the domain is divided into 36-39, 40-43, 44-45 and 46, and the specific measuring point (corresponding to the installation point of the voltage transformer) installation position is 36, 40, 44 and 46. Figure 4 The positioning protection result of the embodiment of the application is a schematic diagram of a fault condition in which the fault area is 17-18.

[0089] The embodiment of the application applies a protection method of a power distribution network based on an orthogonal matching pursuit algorithm, and performs simulation verification and comparison with existing fault protection methods, and the comparison results are shown in Tables 1 and 2.

[0090] Table 1

[0091]

[0092] Table 1 is the positioning result under different fault conditions. Among them, f (1) represents a single-phase fault, f (1,1) represents a two-phase ground fault, f (2) represents a two-phase interphase fault, f (3) represents a three-phase fault, and f all represents the sum of all fault results.

[0093] Table 2

[0094]

[0095] Table 2 is the comparison result of the protection method of the power distribution network based on the orthogonal matching pursuit algorithm and the existing fault positioning protection method, wherein the method type is: the protection method of the power distribution network based on the orthogonal matching pursuit algorithm (method 1), the matrix algorithm (method 2), the fault feature matching method (method 3), the multi-end synchronous measurement method (method 4) and the Bayesian compressed sensing method (method 5).

[0096] According to the results of Tables 1 and 2, it can be obtained that the protection method of the power distribution network based on the orthogonal matching pursuit of the embodiment of the application has good action performance and can basically correctly act under different fault types, and has better action performance than other typical positioning protection methods.

[0097] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0098] The embodiment of the present application further provides a power distribution network protection device. It should be noted that the power distribution network protection device of the embodiment of the present application can be used to execute the power distribution network protection method provided by the embodiment of the present application. The power distribution network protection device provided by the embodiment of the present application is introduced as follows.

[0099] Figure 5 FIG. 1 is a schematic diagram of a power distribution network protection device according to the embodiment of the present application. As shown in the figure, the device comprises a construction unit 501, a first determination unit 502, a second determination unit 503, a calculation unit 504 and a control unit 505. Figure 5

[0100] The construction unit 501 is configured to acquire node voltages of H target node partitions of a power distribution line, divide a plurality of domains according to the H target node partitions, and construct node voltage fault components of the domains based on the node voltages of each domain, wherein each node partition is acquired through a voltage transformer, the number of voltage transformers is less than the number of nodes in the node partition, each domain comprises a plurality of target node partitions, the target node partition comprises at least two nodes, and H is a positive integer.

[0101] The first determination unit 502 is configured to determine a node impedance matrix of each domain according to the impedance size of the power distribution line and the impedance size of a transformer, wherein the transformer is arranged between a power supply and the power distribution line.

[0102] The second determination unit 503 is configured to determine a node current fault component to be solved of each domain according to the node voltage fault component of the domain and the node impedance matrix of the domain, wherein the node current fault component comprises currents of a plurality of nodes.

[0103] The calculation unit 504 is configured to calculate the node current fault component to be solved of each domain based on an orthogonal matching pursuit algorithm, and solve the node current fault component of each domain.

[0104] The control unit 505 is configured to determine a fault area according to the relationship between each node current in the node current fault component of each domain and a node current fault threshold in each domain, and control the nodes at both ends of the fault area to be disconnected.

[0105] ​The protection device of the power distribution network provided in the embodiments of the present application comprises a construction unit 501, which obtains node voltages of H target node partitions of a power distribution line, divides a plurality of domains according to the H target node partitions, and constructs node voltage fault components of the domains based on the node voltages of each domain, wherein each node partition is obtained by a voltage transformer, the number of the voltage transformers is less than the number of nodes in the node partitions, each domain comprises a plurality of target node partitions, at least two nodes are included in each target node partition, H is a positive integer; a first determination unit 502 is configured to determine a node impedance matrix of each domain according to the impedance of the power distribution line and the impedance of a transformer, wherein the transformer is arranged between a power supply and the power distribution line; a second determination unit 503 is configured to determine, for each domain, a node current fault component to be solved of the domain according to the node voltage fault components of the domain and the node impedance matrix of the domain, wherein the node current fault component comprises currents of a plurality of nodes; a calculation unit 504 is configured to calculate the node current fault component to be solved of each domain based on an orthogonal matching pursuit algorithm, and obtain the node current fault component of each domain; and a control unit 505 is configured to determine a fault area according to the relationship between each node current in the node current fault component of each domain and a node current fault threshold, and control the nodes at both ends of the fault area to be disconnected, thereby solving the problem that the traditional protection technology of the power distribution network has a long time consumption and low accuracy in locating a fault point, and affecting the safety of the power distribution network. The fault point is determined by a small number of measuring points of the voltage transformers and the orthogonal matching pursuit algorithm, thereby achieving the effect of accurately and rapidly locating the fault point.

[0106] Optionally, in the protection device of the power distribution network provided in the embodiments of the present application, the device further comprises a third determination unit configured to determine a topology of the power distribution line before obtaining the target node voltages of the H target node partitions of the power distribution line, wherein the power distribution line comprises G initial node partitions, G is a positive integer, and G is less than H; a calculation unit configured to calculate, for each initial node partition, a voltage difference of the initial node partition according to a first end node voltage and a last end node voltage of the initial node partition; a comparison unit configured to compare the voltage differences of the G initial node partitions with a voltage difference threshold respectively, to obtain H1 first initial node partitions and H2 second initial node partitions, wherein the voltage differences of the H1 first initial node partitions are greater than the voltage difference threshold, the voltage differences of the H2 second initial node partitions are less than or equal to the voltage difference threshold, and H1+H2=G; and a splitting unit configured to split each first initial node partition in the H1 first initial node partitions to obtain H3 first target node partitions, wherein the H3 first target node partitions and the H2 first initial node partitions constitute the H target node partitions, and H2+H3=H.

[0107] Optionally, in the power distribution network protection device provided by the embodiment of the present application, the first determining unit comprises: a first determining subunit, configured to determine an initial node impedance matrix, wherein an element in the initial node impedance matrix represents a relationship of complex impedance between two nodes; a second determining subunit, configured to, for each node connected to the distributed photovoltaic power supply, determine an additional impedance of the distributed photovoltaic power supply according to an output current of the distributed photovoltaic power supply, and add the initial impedance of the node and the additional impedance to obtain a target impedance; a third determining subunit, configured to, for each node not connected to the distributed photovoltaic power supply, determine the initial impedance of the node as the target impedance; and a fourth determining subunit, configured to determine the node impedance matrix of each domain according to the target impedance of all nodes connected to the distributed photovoltaic power supply and the target impedance of all nodes not connected to the distributed photovoltaic power supply in each domain.

[0108] Optionally, in the power distribution network protection device provided by the embodiment of the present application, the second determining unit comprises: a calculating subunit, configured to calculate a current value of each node in each domain according to the node voltage fault component of each domain and the target node impedance matrix of each domain; and a solving subunit, configured to obtain the node current fault component of each domain to be solved according to the current value of all nodes in each domain.

[0109] Optionally, in the power distribution network protection device provided by the embodiment of the present application, the second determining subunit comprises: a first measuring module, configured to measure the voltage of the node connected to the distributed photovoltaic power supply, and determine the measured voltage as a distributed photovoltaic voltage fault component phasor; a second measuring module, configured to measure the current of the node connected to the distributed photovoltaic power supply, and determine the measured current as a distributed photovoltaic current fault component phasor; and a calculating module, configured to calculate the distributed photovoltaic impedance of the node connected to the distributed photovoltaic power supply by using the distributed photovoltaic voltage fault component phasor and the distributed photovoltaic current fault component phasor, and obtain the additional impedance.

[0110] Optionally, in the power distribution network protection device provided by the embodiment of the present application, the calculation unit comprises: an acquisition subunit, configured to acquire an inverse matrix of a node impedance matrix of each domain; an inner product subunit, configured to perform inner product calculation on each column of the inverse matrix and a node voltage fault component to obtain a plurality of inner product values; a third determination subunit, configured to take a maximum value from the plurality of inner product values and determine a column where the maximum value is located; an iteration subunit, configured to calculate a difference between the node voltage fault component and an orthogonal projection matrix of the column to obtain a residual of one iteration calculation; a reconstruction subunit, configured to obtain a reconstruction result of a node current fault component of each domain by calculating residuals of multiple iterations, wherein the multiple iterations are performed by an updated orthogonal projection matrix each time, the updated orthogonal projection matrix is obtained by adding a new maximum value to the orthogonal projection matrix of the last iteration calculation, the new maximum value is determined by a new plurality of inner product values, and the new plurality of inner product values are obtained by performing inner product calculation on the inverse matrix after the maximum value is taken from the inverse matrix of the last iteration calculation and the node voltage fault component; and a construction subunit, configured to construct the node current fault component of each domain according to the reconstruction result.

[0111] Optionally, in the power distribution network protection device provided by the embodiment of the present application, the control unit comprises: a fourth determination subunit, configured to determine a maximum value and a second maximum value of node currents of a nodes of a target node partition of each domain by the node current fault component of each domain; and a control subunit, configured to determine the node corresponding to the maximum value and the node corresponding to the second maximum value as two sides of a fault area when the maximum value and the second maximum value are both greater than a node current fault threshold value, and control the nodes at two ends of the fault area to be disconnected, wherein the node corresponding to the maximum value and the node corresponding to the second maximum value are two adjacent nodes.

[0112] The power distribution network protection device comprises a processor and a memory, the construction unit 501, the first determination unit 502, the second determination unit 503, the calculation unit 504 and the control unit 505 are all stored in the memory as program units, and the corresponding functions are realized by the processor executing the program units stored in the memory.

[0113] The processor comprises a core, and the core retrieves the corresponding program units from the memory. The core can be set to one or more, and the fault point is accurately and rapidly located by adjusting the core parameters.

[0114] The memory can comprise a non-permanent memory in a computer readable medium, a random access memory (RAM) and / or a non-volatile memory such as a read-only memory (ROM) or a flash memory (flash RAM), and the memory comprises at least one memory chip.

[0115] The embodiment of the present application further provides an electronic device, Figure 6Fig. 1 is a schematic diagram of an electronic device according to an embodiment of the present application. The electronic device 60 comprises a processor and a memory. The memory stores computer readable instructions, and the processor is configured to execute the computer readable instructions. The computer readable instructions, when executed, implement a method for protecting a power distribution network. The electronic device can be a server, a PC, a PAD, a mobile phone, or the like.

[0116] The embodiment of the present application further provides a computer program product, including a nonvolatile computer readable storage medium, and the nonvolatile computer readable storage medium stores a computer program. The computer program is executed by a processor to implement the following method steps: obtaining node voltages of H target node partitions of a power distribution line, dividing a plurality of domains according to the H target node partitions, constructing node voltage fault components of the domains based on node voltages of each domain, wherein each node partition is obtained by a voltage transformer, the number of voltage transformers is less than the number of nodes in the node partition, each domain includes a plurality of target node partitions, the target node partition includes at least two nodes, and H is a positive integer; determining a node impedance matrix of each domain according to the impedance of the power distribution line and the impedance of a transformer, wherein the transformer is arranged between a power supply and the power distribution line; for each domain, determining a node current fault component to be solved of the domain according to the node voltage fault component of the domain and the node impedance matrix of the domain, wherein the node current fault component includes currents of a plurality of nodes; calculating the node current fault component to be solved of each domain based on an orthogonal matching pursuit algorithm, and solving the node current fault component of each domain; and in each domain, determining a fault area according to a relationship between each node current in the node current fault component of the domain and a node current fault threshold, and controlling nodes at two ends of the fault area to be disconnected.

[0117] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can be in the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can be in the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0118] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0119] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0120] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0121] In one typical configuration, the computing device includes one or more processors (CPU's), input / output interfaces, network interfaces, and memory.

[0122] The memory can include non-persistent memory and / or persistent memory, such as flash memory, read-only memory (ROM), and / or volatile or non-volatile random access memory (RAM), among others. The memory is an example of computer readable media.

[0123] Computer-readable media includes permanent and non-permanent, movable and non-movable media that can implement information storage by any method or technology. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer-readable media does not include transitory media such as modulated data signals and carriers.

[0124] It should also be noted that the terms "comprising", "containing", or any other variant thereof are intended to cover non-exclusive inclusions, so that a process, method, article or apparatus that includes a list of elements does not only include those elements, but also includes other elements not explicitly listed, or further includes elements inherent in such a process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0125] The above only is an embodiment of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A protection method for a power distribution network, characterized in that, Distribution lines used in power distribution network systems include: Obtain the node voltages of H target node partitions of the power distribution line, divide the H target node partitions into multiple domains, and construct the node voltage fault component of the domain based on the node voltage of each domain. Each node voltage is obtained through a voltage transformer, the number of voltage transformers is less than the number of nodes in the target node partitions, each domain includes multiple target node partitions, and each target node partition includes at least two nodes. H is a positive integer. Based on the impedance of the power distribution line and the impedance of the transformer, determine the node impedance matrix of each domain, wherein the transformer is located between the power source and the power distribution line. For each domain, the node current fault component to be solved is determined based on the node voltage fault component of the domain and the node impedance matrix of the domain, wherein the node current fault component includes the current of multiple nodes. The node current fault components to be solved in each domain are calculated based on the orthogonal matching pursuit algorithm, and the node current fault components in each domain are obtained. In each domain, a fault region is determined based on the relationship between each node current and the node current fault threshold in the node current fault component of the domain, and the nodes at both ends of the fault region are controlled to disconnect. The node current fault components to be solved in each domain are calculated based on the orthogonal matching pursuit algorithm, and the node current fault components in each domain are obtained as follows: Obtain the inverse matrix of the node impedance matrix of each domain, perform an inner product calculation on each column of the inverse matrix with the initial residual to obtain multiple inner product values, determine the column containing the maximum inner product value among the multiple inner product values, and calculate the difference between the node voltage fault component and the orthogonal projection matrix of the column containing the maximum inner product value to obtain the residual of the first iteration calculation, wherein the initial residual represents the node voltage fault component of the domain; Remove the column corresponding to the maximum inner product value from the previous iteration calculation from the inverse matrix to obtain the updated inverse matrix. Perform inner product calculation on each column of the updated inverse matrix with the residual of the first iteration calculation to obtain multiple updated inner product values. Determine the column containing the updated maximum inner product value among the multiple updated inner product values, and calculate the difference between the orthogonal projection matrix of the node voltage fault component and the column containing the updated maximum inner product value to obtain the residual of the second iteration calculation. The calculation is iterated until the termination condition of the iterative calculation is reached. A one-dimensional vector is constructed based on the multiple maximum inner product values ​​obtained from the multiple iterations. The node current fault component of each domain is determined according to the one-dimensional vector, wherein each maximum inner product value represents each element in the one-dimensional vector.

2. The protection method for a power distribution network according to claim 1, characterized in that, Before obtaining the node voltages of the H target node zones of the power distribution line, the method further includes: Determine the topology of the power distribution line, wherein the power distribution line includes G initial node partitions, where G is a positive integer and G is less than H; For each initial node partition, the voltage difference of the initial node partition is calculated based on the voltage of the first node and the voltage of the last node of the initial node partition; The voltage difference and voltage difference threshold of the G initial node partitions are compared respectively to obtain H1 first initial node partitions and H2 second initial node partitions, wherein the voltage difference of the H1 first initial node partitions is greater than the voltage difference threshold, and the voltage difference of the H2 second initial node partitions is less than or equal to the voltage difference threshold, and H1+H2=G; Each of the H1 first initial node partitions is split to obtain H3 first target node partitions. The H target node partitions are composed of the H3 first target node partitions and the H2 second initial node partitions, and H2 + H3 = H.

3. The protection method for a power distribution network according to claim 1, characterized in that, The method for determining the node impedance matrix of each domain based on the impedance of the power distribution line and the impedance of the transformer includes: Determine an initial node impedance matrix, wherein the elements in the initial node impedance matrix represent the complex impedance relationship between any two nodes; For each node connected to the distributed photovoltaic power source, the additional impedance of the distributed photovoltaic power source is determined based on the output current of the distributed photovoltaic power source. The initial impedance of the node and the node impedance of the additional impedance are added together to obtain the target impedance. For each node that is not connected to a distributed photovoltaic power source, the initial impedance of the node is determined as the target impedance; The node impedance matrix of each domain is determined by the target impedance of all nodes connected to distributed photovoltaic power sources and the target impedance of all nodes not connected to distributed photovoltaic power sources.

4. The protection method for a power distribution network according to claim 1, characterized in that, For each domain, based on the node voltage fault components and the node impedance matrix of the domain, the node current fault components to be solved for the domain are determined as follows: For each domain, the current value of each node in the domain is calculated based on the node voltage fault component of the domain and the target node impedance matrix of the domain. Based on the current values ​​of all nodes in the domain, construct the node current fault components to be solved for the domain.

5. The protection method for a power distribution network according to claim 3, characterized in that, For each node connected to the distributed photovoltaic (PV) power source, the additional impedance of the distributed PV power source is determined based on its output current, including: Measure the voltage of the node connected to the distributed photovoltaic power source, and determine the measured voltage as the distributed photovoltaic voltage fault component phasor; The current of the node connected to the distributed photovoltaic power source is measured, and the measured current is determined as the distributed photovoltaic current fault component phasor. The distributed photovoltaic impedance of the node connected to the distributed photovoltaic power source is calculated by using the distributed photovoltaic voltage fault component phasor and the distributed photovoltaic current fault component phasor, and the additional impedance is obtained.

6. The protection method for a power distribution network according to claim 1, characterized in that, In each domain, determining a fault region based on the relationship between each node current and the node current fault threshold in the node current fault component of the domain, and controlling the disconnection of the nodes at both ends of the fault region includes: By using the node current fault components of each domain, determine the maximum and second largest values ​​of the node currents of the a nodes in the target node partition of each domain. When both the maximum value and the second largest value are greater than the node current fault threshold, the node corresponding to the maximum value and the node corresponding to the second largest value are determined to be the two sides of the fault region, and the nodes at both ends of the fault region are controlled to disconnect. The node corresponding to the maximum value and the node corresponding to the second largest value are two adjacent nodes.

7. A protection device for a power distribution network, characterized in that, A protection method for implementing the power distribution network according to any one of claims 1 to 6, comprising: A construction unit is used to obtain the node voltages of H target node partitions of a power distribution line, divide the H target node partitions into multiple domains, and construct the node voltage fault component of each domain based on the node voltage of each domain. Each node voltage is obtained through a voltage transformer, the number of voltage transformers is less than the number of nodes in the target node partitions, each domain includes multiple target node partitions, each target node partition includes at least two nodes, and H is a positive integer. The first determining unit is used to determine the node impedance matrix of each domain based on the impedance of the power distribution line and the impedance of the transformer, wherein the transformer is located between the power source and the power distribution line. The second determining unit is used to determine, for each domain, the node current fault component to be solved in the domain based on the node voltage fault component of the domain and the node impedance matrix of the domain, wherein the node current fault component includes the current of multiple nodes. The calculation unit is used to calculate the node current fault component to be solved in each domain based on the orthogonal matching pursuit algorithm, and to solve for the node current fault component in each domain. The control unit is configured to determine a fault region in each domain based on the relationship between the node currents and node current fault thresholds in the node current fault components of the domain, and to control the nodes at both ends of the fault region to disconnect.

8. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to execute the power distribution network protection method according to any one of claims 1 to 6 through the computer program.

9. A computer program product, characterized in that, The method includes a non-volatile computer-readable storage medium storing a computer program that, when executed by a processor, implements the power distribution network protection method according to any one of claims 1 to 6.

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