Grounding grid measuring point optimization arrangement method based on considerable network topology

Abstract

The invention discloses a grounding grid measuring point optimization arrangement method based on considerable network topology, and belongs to the technical field of substation grounding grid corrosion diagnosis. According to the method, firstly, an accessible node matrix and a node adjacent matrix of the grounding grid are established, the network topology observability of the grounding grid is analyzed, then, the observable inequality constraint of the grounding grid is established according to the network topology observability, a measuring point optimal configuration model is further deduced, and finally, a target measuring point set is obtained. The test point optimization of the grounding grid and the comprehensive testability of the grounding grid are realized, and the test process is simplified. Furthermore, under limited measuring point resources, grounding grid branch information is obtained as much as possible, comprehensive diagnosis coverage is ensured, the accuracy of grounding grid diagnosis is improved, and unnecessary measuring point redundancy is reduced.

Description

Technical Field

[0001] The invention relates to a corrosion diagnosis technology for a substation grounding grid, in particular to a grounding grid measuring point optimization arrangement method based on an observable network topology. Background Art

[0002] The grounding grid is an important equipment of the substation, which can ensure the stable operation of the substation and the life safety of the operation and maintenance personnel, and ensure the stable operation of the power system. Since the substation grounding grid is buried deep underground, it is easily affected by corrosive substances and microorganisms in the soil, resulting in corrosion of the grounding grid. If the corrosion cannot be discovered and repaired in time, it will seriously threaten the stable operation of the substation and the safety of personnel.

[0003] In order to ensure the smooth operation of the grounding grid, it is necessary to diagnose the corrosion of the grounding grid. At present, there are three main methods for diagnosing the corrosion of the grounding grid: electromagnetic field analysis, electrochemical analysis and electrical network analysis. Among them, the electrical network analysis method is a relatively mature and easy-to-implement method. It injects DC current into the grounding grid, measures the response voltage of different ports, establishes a fault equation to solve the branch resistance value, and compares it with the original resistance value to obtain the corrosion condition of the grounding grid. The electrical network analysis method has the advantages of simple principle, convenient implementation, and not susceptible to electromagnetic interference. However, in actual operation, the number of existing equipment down conductors in the substation is small. The test only through the equipment down conductor makes the scope of diagnosis limited to a small area where the equipment down conductor is located. If the measurement range is expanded, it is necessary to excavate the area where there is no accessible node. Since the grounding grid is buried deep underground, if there are too many test nodes, the workload of excavation is large, and the test process will be more cumbersome, which increases the workload and cost of corrosion diagnosis.

[0004] A Chinese patent application with publication number CN113687191A discloses a grounding grid fault diagnosis method based on the combination of electrical impedance imaging technology and electrical network theory. The method uses the sensitivity characteristics of the fault branch of the grounding grid to detect faults in the grounding grid, measures the port resistance, performs electrical impedance imaging on the fault area, and uses soil separation to image the corrosion site to achieve accurate positioning and diagnosis. The above method detects faults in the grounding grid through the sensitivity characteristics of the fault branch of the grounding grid. There are too many nodes to be tested, and the testing process is complicated. The prior art needs to be further improved. To this end, the present invention proposes a method for optimizing the layout of grounding grid measurement points based on an observable network topology. The method can accurately diagnose grounding grid corrosion in a larger area with fewer measurement nodes. Summary of the invention

[0005] In order to solve the defects of the above-mentioned prior art, the present invention proposes a method for optimizing the arrangement of grounding grid measuring points based on observable network topology. The present invention first establishes the accessible node matrix and node adjacency matrix of the grounding grid, then observable inequality constraints of the grounding grid are established according to the network topology, and then the measuring point optimization configuration model is introduced, and finally the target measuring point set is obtained, thereby realizing the optimization of the measuring points of the grounding grid and simplifying the test process.

[0006] The technical solution of the present invention is achieved in this way: A method for optimizing the arrangement of grounding grid measuring points based on an observable network topology comprises the following steps: Step 1: Number the nodes of the grounding grid and sort the nodes in ascending order to form a node set X; Step 2: Establish the accessible node matrix B of the grounding grid n×1 , where the nodes on the substation grounding network connected to the down conductor are accessible nodes; Step 3: Establish the node adjacency matrix A of the grounding grid n×1 , where the node adjacency matrix in the grounding grid is a matrix that describes the adjacency relationship between nodes; Step 4: According to the network topology, the observable inequality constraint C of the grounding grid is established, where the observable inequality constraint C of the grounding grid is: , I n×1 =[1,1,...,1] T ; Step 5: Generate an accessible node matrix set D according to the observable inequality constraint C, where the node matrix set D is all accessible node matrices that satisfy the observable inequality constraint C; Step 6: Obtain a measurement point optimization configuration model based on observable inequality constraints, and solve the measurement point optimization configuration model to obtain a target measurement point set.

[0007] In the present invention, in step 1, according to the substation grounding grid design drawing, all nodes of the substation grounding grid are numbered from left to right and from top to bottom, and the node set X={x1,x2,x3,...,x n}, n represents the number of all nodes in the grounding grid.

[0008] In the present invention, in step 2, the accessible node numbers are determined and the accessible node matrix B is established. n×1 =[b1,b2,...,b j ,...,b n ] T , , b j Represents the value of the jth row and first column in the reachable node matrix.

[0009] In the present invention, in step 3, the node adjacency matrix can clearly reflect the adjacency of all nodes in the grounding grid. , , element a ij Represents the value of the i-th row and j-th column in the node adjacency matrix.

[0010] In the present invention, in step 4, the node whose voltage can be directly measured or calculated through other voltages and currents is an observable node, and the node adjacent to the accessible node is an observable node. When all nodes in the grounding grid are observable nodes, the grounding grid has an observable network topology.

[0011] In the present invention, in step 5, D={D (n×1)1 ,D (n×1)2 ,...,D (n×1)m ,...,D (n×1)M}, D (n×1)m is the mth accessible node matrix in the accessible node matrix set, D (n×1)m ={d 1m ,d 2m ,...,d nm}, M is the number of accessible node matrices in the reachable node matrix set.

[0012] In the present invention, in step 6, the elements and z of the accessible node matrix in the accessible node matrix set are calculated. m , establish the measurement point optimization configuration model , the target accessible node matrix is ​​obtained according to the measurement point optimization configuration model, Z is the element of the accessible node matrix in the accessible node matrix set and z m The target accessible node matrix is ​​the target measurement point set.

[0013] The implementation of the grounding grid measurement point optimization arrangement method based on the observable network topology of the present invention has the following beneficial effects: the present invention obtains the optimal measurement point arrangement method of the grounding grid by analyzing the observability of the grounding grid network topology, and finally realizes the comprehensive measurability of the grounding grid. Furthermore, under the limited measurement point resources, as much grounding grid branch information as possible is obtained to ensure comprehensive diagnosis coverage, improve the accuracy of grounding grid diagnosis, and reduce unnecessary measurement point redundancy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flow chart of the method for optimizing the arrangement of grounding grid measuring points based on the observable network topology of the present invention; Figure 2 A schematic diagram of the network topology of the substation grounding grid of the present invention; Figure 3 It is a schematic diagram of the network topology structure after the substation grounding network of the present invention is numbered; DETAILED DESCRIPTION

[0015] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0016] like Figures 1 to 3 As shown, the method for optimizing the arrangement of grounding grid measuring points based on the observable network topology of the present invention includes the following steps.

[0017] Step 1: Number the nodes of the grounding grid and sort the nodes in ascending order to form a node set X. According to the substation grounding grid design drawing, number all nodes of the substation grounding grid from left to right and from top to bottom, and sort all nodes in ascending order to form a node set X={x1,x2,x3,...,x n}, n represents the number of all nodes in the grounding grid. The network topology of the grounding grid is as follows Figure 2 As shown, the circles represent the nodes of the grounding grid, and the straight lines represent the branches of the grounding grid. The grounding grid in the figure contains 16 nodes.

[0018] Step 2: Establish the accessible node matrix B of the grounding grid n×1 , where nodes connected to the substation grounding network with down conductors are accessible nodes. Determine the accessible node numbers and establish the accessible node matrix B n×1 =[b1,b2,...,b j ,...,b n ] T , , b j Represents the value of the jth row and first column in the reachable node matrix.

[0019] In this embodiment, the grounding grid has 16 nodes. The network topology structure after the nodes of the grounding grid are numbered is as follows: Figure 3 As shown in Figure 2, when all nodes of the grounding grid are accessible nodes, the corresponding accessible node matrix is ​​B n×1 =[1,1,...,1,...,1] T When only one of the 16 nodes in the grounding grid is an inaccessible node, the accessible node matrix has In this case, the matrix of all reachable nodes is shown in Table 1.

[0020]

[0021] When only two of the 16 nodes in the grounding grid are inaccessible, the accessible node matrix has In this case, the matrix of all reachable nodes is shown in Table 2.

[0022]

[0023] Similarly, when three nodes cannot be kind of accessible node matrix, ..., when fifteen nodes are not available, there is Finally, all the situations are summarized to get the total number of accessible nodes in the grounding grid. A matrix of reachable nodes.

[0024] Step 3: Establish the node adjacency matrix A of the grounding grid n×1 , where the node adjacency matrix in the grounding grid is a matrix that describes the adjacency relationship between nodes. The node adjacency matrix can clearly reflect the adjacency of all nodes in the grounding grid. , , element a ij represents the value of the i-th row and j-th column in the node adjacency matrix. In this embodiment, A n×n = .

[0025] Step 4: According to the network topology, the observable inequality constraint of the grounding grid is established, where the observable inequality constraint C of the grounding grid is: , I n×1 =[1,1,...,1] T . A node whose voltage can be directly measured or calculated through other voltages and currents is an observable node, and a node adjacent to an accessible node is an observable node. When all nodes in the grounding grid are observable nodes, the grounding grid is an observable network topology. In this embodiment, the following inequality constraints can be obtained according to the node adjacency matrix of the grounding grid: x1+x2+x5≥1, x1+x2+ x3+x6≥1, x2+x3+x4+x7≥1, x3+x4+x8≥1, x1+x5+x6+x9≥1, x2+x5+x6+x7+x 10 ≥1, x3+x6+x7+x8+x 11 ≥1, x4+x7+x8+x 12 ≥1, x5+x9+x 10 +x 13 ≥1, x6+x9+x 10 +x 11 +x 14 ≥1, x7+x 10 +x 11 +x 12 +x 13 ≥1, x8+x 11 +x 12 +x 16 ≥1, x9+x 13 +x 14 ≥1,x 10 +x13 +x 14 +x 15 ≥1,x 11 +x 14 +x 15 +x 16 ≥1,x 12 +x 15 +x 16 ≥1. The above formula can be written in matrix form to obtain the observable inequality constraint C: A 16× 16 B 16×1 =I 16×1 , A 16×16 is the node adjacency matrix of the grounding grid in this embodiment, B 16×1 is the accessible node matrix of the grounding grid in this embodiment.

[0026] Step 5: Generate an accessible node matrix set D according to the observable inequality constraint C, where the node matrix set D is all accessible node matrices that satisfy the observable inequality constraint C. The node matrix set D is all accessible node matrices that satisfy the observable inequality constraint C, D={D (n×1)1 ,D (n×1)2 ,...,D (n×1)m ,...,D (n×1)M}, D (n×1)m is the mth accessible node matrix in the accessible node matrix set, D (n×1)m ={d 1m ,d 2m ,...,d nm}, M is the number of accessible node matrices in the accessible node matrix set. In this embodiment, the accessible node matrix set D is calculated by integer programming.

[0027] Step 6: Obtain the measurement point optimization configuration model based on the observable inequality constraints, and solve the measurement point optimization configuration model to obtain the target measurement point set. Calculate the elements and z of the accessible node matrix in the accessible node matrix set m , establish the measurement point optimization configuration model , the target accessible node matrix is ​​obtained according to the measurement point optimization configuration model, Z is the element of the accessible node matrix in the accessible node matrix set and z m The target accessible node matrix is ​​the target measuring point set. In this embodiment, the element sum of all accessible node matrices in the accessible node matrix set D is calculated, and the minimum value is obtained. According to the measuring point optimization configuration model, Z=4 is obtained, that is, the minimum number of accessible nodes that can make the grounding grid observable is 4. In this embodiment, the accessible node matrices that satisfy Z=4 are D (16×1)1 =[0,0,1,0,1,0,0,0,0,0,0,1,0,1,0,0], D (16×1)2=[0,1,0,0,0,0,0,0,1,1,0,0,0,0,0,1,0], from the accessible node matrix D (16×1)1 The corresponding target measurement point set Y1={x2,x5,x 12 ,x 14}, from the accessible node matrix D (16×1)2 The target measurement point set Y1={x2,x8,x9,x 15}.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for optimizing the arrangement of grounding grid measuring points based on an observable network topology, characterized in that: The following steps are involved: Step 1: Number the nodes of the grounding grid and sort the nodes in ascending order to form a node set X; Step 2: Establish the accessible node matrix B of the grounding grid n×1 , where the nodes on the substation grounding network connected to the down conductor are accessible nodes; Step 3: Establish the node adjacency matrix A of the grounding grid n×1 , where the node adjacency matrix in the grounding grid is a matrix that describes the adjacency relationship between nodes; Step 4: According to the network topology, the observable inequality constraint C of the grounding grid is established, where the observable inequality constraint C of the grounding grid is: , I n×1 =[1,1,...,1] T ; Step 5: Generate an accessible node matrix set D according to the observable inequality constraint C, where the node matrix set D is all accessible node matrices that satisfy the observable inequality constraint C; Step 6: Obtain a measurement point optimization configuration model based on observable inequality constraints, and solve the measurement point optimization configuration model to obtain a target measurement point set.

2. The method for optimizing the arrangement of grounding grid measuring points based on observable network topology according to claim 1 is characterized in that: In step 1, according to the substation grounding grid design drawing, all nodes of the substation grounding grid are numbered from left to right and from top to bottom. The node set X = {x1, x2, x3, ..., x n }, n represents the number of all nodes in the grounding grid.

3. The method for optimizing the arrangement of grounding grid measuring points based on observable network topology according to claim 1 is characterized in that: In step 2, determine the accessible node numbers and establish the accessible node matrix B n×1 =[b1,b2,...,b j ,...,b n ] T , , b j Represents the value of the jth row and first column in the reachable node matrix.

4. The method for optimizing the arrangement of grounding grid measuring points based on observable network topology according to claim 1 is characterized in that: In step 3, the node adjacency matrix can clearly reflect the adjacency of all nodes in the grounding grid. , , element a ij Represents the value of the i-th row and j-th column in the node adjacency matrix.

5. The method for optimizing the arrangement of grounding grid measuring points based on observable network topology according to claim 1 is characterized in that: In step 4, nodes whose voltage can be directly measured or calculated through other voltages and currents are observable nodes, and nodes adjacent to accessible nodes are observable nodes. When all nodes in the grounding grid are observable nodes, the grounding grid is topologically observable.

6. The method for optimizing the arrangement of grounding grid measuring points based on observable network topology according to claim 1 is characterized in that: In step 5, D = {D (n×1)1 ,D (n×1)2 ,...,D (n×1)m ,...,D (n×1)M }, D (n×1)m is the mth accessible node matrix in the accessible node matrix set, D (n×1)m ={d 1m ,d 2m ,...,d nm }, M is the number of accessible node matrices in the reachable node matrix set.

7. The method for optimizing the arrangement of grounding grid measuring points based on observable network topology according to claim 6 is characterized in that: In step 6, the sum of the elements of the reachable node matrix in the reachable node matrix set is calculated. m , establish the measurement point optimization configuration model , the target accessible node matrix is ​​obtained according to the measurement point optimization configuration model, Z is the element of the accessible node matrix in the accessible node matrix set and z m The target accessible node matrix is ​​the target measurement point set.

Images