A method for optimizing the layout of grounding grid measuring points in substations

Abstract

This invention discloses an optimized layout method for measuring points in substation grounding grids, belonging to the field of power system technology. Before diagnosing the substation grounding grid, this invention outputs the optimal number and location of measuring points. By concentrating on key areas and sensitive locations, it not only saves testing workload but also improves diagnostic accuracy. Different optimized measuring point layout schemes are proposed for different substations, enhancing the early warning capability for grounding grid corrosion faults. Maintenance personnel can quickly locate problems, reduce troubleshooting time, improve maintenance efficiency, and lower maintenance costs.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a method for optimizing the layout of grounding grid measuring points in substations. Background Technology

[0002] As a crucial component of the power system, the substation grounding grid's primary function is to provide safe electrical grounding for electrical equipment, ensuring personal safety and the normal operation of the equipment. By diverting current into the ground, the grounding grid quickly eliminates fault currents in the power system, thus preventing harm to personnel and equipment. Corrosion of the grounding grid is one of the main causes of defects, leading to numerous accidents. Therefore, the detection and diagnosis of grounding grid corrosion is of paramount importance for accurately understanding its operational status, promptly identifying potential problems, and taking appropriate measures.

[0003] Currently, there are three main methods for diagnosing grounding grid corrosion: electromagnetic field method, electrochemical measurement method, and electrical network theory method. Among them, the electrical network theory method is a commonly used method due to its simple principle, convenient implementation, immunity to electromagnetic interference, and lack of soil excavation requirement. The electrical network method involves injecting a direct current between grounding grid nodes, measuring the voltage between the two injected nodes, calculating the corresponding grounding grid port resistance using voltage and current, and then using electrical network theory and Tellegen's theorem to solve for the branch resistance of the grounding grid based on the port resistance. The actual resistance of the branch is compared with the theoretical resistance to determine the degree of corrosion in the branch. However, in practice, substations have a limited number of existing equipment grounding down conductors, limiting the number of measurement points that can be obtained by injecting direct current into the existing down conductors as observation points, and restricting the branches that can be solved to the area where the down conductors are located. Furthermore, since the grounding grid is buried underground, adding a lead-out terminal to each node for measurement would be cumbersome, labor-intensive, and costly. Therefore, this invention proposes a method for optimizing the arrangement of grounding grid measurement nodes. This method determines the observation nodes of the grounding grid and achieves accurate diagnosis of corrosion of grounding grid branches with as few measurement nodes as possible. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes an optimized arrangement method for measuring points in substation grounding grids. Before testing the substation grounding grid, this method outputs the optimal number and location of measuring points, saving workload and improving accuracy.

[0005] The technical solution of this invention is implemented as follows:

[0006] A method for optimizing the layout of grounding grid measuring points in substations, comprising the following steps:

[0007] Step 1: Based on the grounding grid structure, establish the grounding grid correlation matrix and grounding grid parameter vector:

[0008] (1) Based on the substation grounding grid design drawings, analyze the topology between its branches and nodes, and generate the grounding grid correlation matrix A.

[0009] (2) Based on the grounding grid branch in the substation grounding grid design drawings, calculate the nominal resistance value of the grounding grid branch, and calculate the branch conductance matrix Y by calculating the nominal resistance value vector of the grounding grid branch. b b represents the number of branches.

[0010] (3) Calculate the admittance matrix Y of the grounding grid node n =AY b A T ;

[0011] Step 2: Select all nodes of the grounding grid as measurement points to obtain the measurement point set;

[0012] Step 3: Generate a measurement matrix based on the measurement point set, and calculate the column correlation coefficients of the measurement matrix. ,in, Let r be the measurement matrix, and r be the number of measurement nodes in the selected set of measurement points.

[0013] Step 4: Analyze the observability of the measurement matrix and determine whether the correlation coefficients of the measurement matrix columns satisfy the following: Z represents the number of corroded branches in the grounding grid. If the condition is met, output the current set of measurement points and proceed to step 6. If the condition is not met, proceed to step 5.

[0014] Step 5: Remove one measurement point from the measurement point set and find the one with the smallest increase in the column correlation coefficient. Return to step 3 with the set of measurement points;

[0015] Step 6: Determine the optimal set of measurement nodes and deploy them on-site according to their locations, i.e., output the set of optimal node numbers { }

[0016] In this invention, in step 1, , ,in, This represents the value in the i-th row and j-th column of the grounding grid correlation matrix, where i represents the node number, j represents the branch number, and n represents the number of nodes.

[0017] In this invention, in step 1, the nominal resistance value of grounding grid branch j is... j = 1,2,3,...,b The resistivity of the grounding grid branch, Let j be the length of the grounding grid branch. Let be the cross-sectional area of ​​grounding grid branch j, and be the vector of nominal resistance values ​​of the grounding grid branch. Branch conductance matrix , It is a diagonal matrix, with diagonal elements as follows: The reciprocal of the first element, with all other elements being 0.

[0018] In this invention, in step 2, the measurement point set is {1,2,L,…,n}.

[0019] In this invention, step 3 includes:

[0020] (1) Based on the measurement point set, arbitrarily select a reference node and generate the current vector. ;

[0021] (2) Calculate the voltage matrix of the grounding grid nodes ,in, The inverse of the nodal admittance matrix is... For the injected current matrix;

[0022] (3) Calculate the sensitivity between each node and each branch to obtain the measurement matrix of the grounding grid. ;

[0023] (4) Calculate the measurement matrix Column correlation coefficient .

[0024] In this invention, in step 3, , Where r is the number of measurement nodes in the selected set of measurement points, and n is the number of nodes. This represents the element in the i-th row and j-th column of the current vector. The specified injection DC current.

[0025] In this invention, in step 3, the sensitivity ,in, .

[0026] In this invention, in step 3, the measurement matrix .

[0027] In this invention, in step 3, the correlation coefficients are listed. , express The kth column, This represents the inner product of the k-th and j-th columns. Represents the magnitude of a vector.

[0028] In this invention, step 5 includes:

[0029] (1) Remove one measurement point from the measurement point set in sequence to obtain a new measurement point set;

[0030] (2) Calculate the column correlation coefficients of the new measurement matrix sequentially according to the method in step 3;

[0031] (3) Find the column with the smallest increase in correlation coefficient. That is, the set of measurement points, return to step 3.

[0032] The substation grounding grid measurement point optimization layout method of this invention has the following beneficial effects: It outputs the optimal number and location of measurement points before diagnosing the substation grounding grid. Concentrating on key areas and sensitive locations not only saves testing workload but also improves diagnostic accuracy. Different measurement point optimization layout schemes are proposed for different substations, enhancing the early warning capability for grounding grid corrosion faults. Maintenance personnel can quickly locate problems, reducing troubleshooting time, improving maintenance efficiency, and lowering maintenance costs. Attached Figure Description

[0033] Figure 1 This is a flowchart of the substation grounding grid measurement point optimization layout method of the present invention;

[0034] Figure 2 This is a schematic diagram of the grounding grid of the present invention. Detailed Implementation

[0035] To better understand the purpose, technical solution, and advantages of this application, the application is described and illustrated below in conjunction with the accompanying drawings and embodiments. Example 1

[0036] like Figure 1 As shown in the figure, this embodiment discloses a method for optimizing the layout of grounding grid measuring points in a substation. The specific steps are as follows:

[0037] Step 1: Based on the grounding grid structure, establish the grounding grid correlation matrix and grounding grid parameter vector.

[0038] (1) Based on the substation grounding grid design drawings, analyze the topology between its branches and nodes, and generate the grounding grid correlation matrix. , ,in, This represents the value in the i-th row and j-th column of the grounding grid correlation matrix, where i represents the node number, j represents the branch number, n represents the number of nodes, and b represents the number of branches.

[0039] (2) Calculate the nominal resistance value of the grounding grid branch based on the material, length and other parameters of the grounding grid branch in the substation grounding grid design drawings. j = 1,2,3,...,b The resistivity of the grounding grid branch, Let j be the length of the grounding grid branch. Let be the cross-sectional area of ​​grounding grid branch j, and be the vector of nominal resistance values ​​of the grounding grid branch. Branch conductance matrix , It is a diagonal matrix, with diagonal elements as follows: The reciprocal of the first element, with all other elements being 0.

[0040] (3) Calculate the admittance matrix Y of the grounding grid node n =AY b A T .

[0041] Step 2: Select all nodes of the grounding grid as measurement points to obtain the measurement point set {1,2,L,…,n}.

[0042] Step 3: Generate the measurement matrix and calculate the column correlation coefficients of the measurement matrix.

[0043] (1) Based on the measurement point set, arbitrarily select a reference node and generate the current vector according to the following rules. : , Where r is the number of measurement nodes in the selected set of measurement points, and n is the number of nodes. This represents the element in the i-th row and j-th column of the current vector. The specified injection DC current.

[0044] (2) Calculate the voltage matrix of the grounding grid nodes ,in, The inverse of the nodal admittance matrix is... This is the injected current matrix.

[0045] (3) Calculate the sensitivity between each node and each branch. ,in, Measurement matrix of grounding grid : .

[0046] (4) Calculate the measurement matrix Column correlation coefficient Column correlation coefficient , express The kth column, This represents the inner product of the k-th and j-th columns. Represents the magnitude of a vector.

[0047] Step 4: Analyze the observability of the measurement matrix.

[0048] (1) Determine whether the correlation coefficients of the measurement matrix columns satisfy the following formula: Z represents the number of corroded branches in the grounding grid.

[0049] (2) If the condition is met, output the current set of measurement points and proceed to step 6; if the condition is not met, proceed to step 5.

[0050] Step 5: Remove one measurement point from the measurement point set and find the one with the smallest increase in the column correlation coefficient. The set of measurement points.

[0051] (1) Remove one measurement point from the measurement point set in sequence to obtain a new measurement point set.

[0052] (2) Calculate the column correlation coefficients of the new measurement matrix in sequence according to the method in step 3.

[0053] (3) Find the column with the smallest increase in correlation coefficient. Given the set of measurement points, return to step 3.

[0054] Step 6: Determine the optimal set of measurement nodes and deploy them on-site according to their locations.

[0055] (1) Output the set of optimal node numbers { }

[0056] (2) Make donations on site according to the location. Example 2

[0057] like Figure 2 As shown, this embodiment applies the technical solution of the present invention to a specific substation. The node and branch numbers of this substation grounding grid are as follows: Figure 1 As shown, circles represent grounding grid nodes, and rectangles represent grounding grid branches. In this embodiment, it is assumed that branches 1 and 10 are corroded, and their branch resistance is set to 15 ohms, while the other branches are in good condition and their branch resistance is 1 ohm.

[0058] (1) Based on the substation grounding grid design drawings, analyze the topology between its branches and nodes, and generate the grounding grid correlation matrix A. Taking the 3*3 node grounding grid network data as an example, calculate the correlation matrix A of the grounding grid. The grounding grid has an association matrix size of 9×12, meaning that the grounding grid has 9 nodes and 12 branches.

[0059] (2) Based on the material and length of the grounding grid branches, obtain the nominal resistance vector of the grounding grid branches. .

[0060] (3) The branch conductance matrix is ​​calculated based on the obtained nominal branch resistance vector. , .

[0061] (4) Select all nodes of the grounding grid as measurement points to obtain the measurement point set { }

[0062] (5) Inject current into all nodes except the reference node. =20A, with node 9 set as the reference node and the remaining nodes used as measurement points, a current vector is generated. , Then Y n =AY b A T Obtain the nodal conductance matrix Therefore, it can be determined according to the formula. The voltage at each node is obtained. , Then substitute into the formula The measurement matrix can be obtained from it. , .

[0063] (6) According to the formula Calculate the measurement matrix Column correlation coefficient , .

[0064] (7) Set the initial value Z=2.

[0065] (8) Judgment Whether it holds true or not can be determined by substituting the values. If this is not valid, proceed to the next step.

[0066] (9) Remove one measurement point from the grounding grid and recalculate the column correlation coefficient of the new measurement matrix according to the method in step (6) to find the set of measurement points with the smallest increase in column correlation coefficient.

[0067] (10) Recalculate the measurement matrix and column correlation coefficients for the new measurement point set. Determine if the following conditions are met. If the condition is met, output the current set of measurement points; otherwise, return to (8).

[0068] (11) Repeat step (10) for several iterations to finally obtain the set of nodes to be removed. The correlation coefficient of the column after ,at this time Established.

[0069] (12) Output the set of node numbers for the optimal measurement points as follows: .

[0070] 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 principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for optimizing the layout of measuring points in a substation grounding grid, characterized in that, The specific steps are as follows: Step 1: Based on the grounding grid structure, establish the grounding grid correlation matrix and grounding grid parameter vector: (1) Based on the substation grounding grid design drawings, analyze the topology between its branches and nodes, and generate the grounding grid correlation matrix A. (2) Based on the grounding grid branch in the substation grounding grid design drawings, calculate the nominal resistance value of the grounding grid branch, and calculate the branch conductance matrix Y by calculating the nominal resistance value vector of the grounding grid branch. b b represents the number of branches. (3) Calculate the admittance matrix Y of the grounding grid node n =AY b A T ; Step 2: Select all nodes of the grounding grid as measurement points to obtain the measurement point set; Step 3: Generate a measurement matrix based on the measurement point set, and calculate the column correlation coefficients of the measurement matrix. ,in, Let r be the measurement matrix, and r be the number of measurement nodes in the selected set of measurement points. Step 4: Analyze the observability of the measurement matrix and determine whether the correlation coefficients of the measurement matrix columns satisfy the following: Z represents the number of corroded branches in the grounding grid. If the condition is met, output the current set of measurement points and proceed to step 6. If the condition is not met, proceed to step 5. Step 5: Remove one measurement point from the measurement point set and find the one with the smallest increase in the column correlation coefficient. Return to step 3 with the set of measurement points; Step 6: Determine the optimal set of measurement nodes and deploy them on-site according to their locations, i.e., output the set of optimal node numbers { } 2. The method for optimizing the layout of measuring points in a substation grounding grid according to claim 1, characterized in that, In step 1, , ,in, This represents the value in the i-th row and j-th column of the grounding grid correlation matrix, where i represents the node number, j represents the branch number, and n represents the number of nodes.

3. The method for optimizing the layout of measuring points in a substation grounding grid according to claim 1, characterized in that, In step 1, the nominal resistance value of grounding grid branch j j = 1,2,3,...,b The resistivity of the grounding grid branch, Let j be the length of the grounding grid branch. Let be the cross-sectional area of ​​grounding grid branch j, and be the vector of nominal resistance values ​​of the grounding grid branch. Branch conductance matrix , It is a diagonal matrix, with diagonal elements as follows: The reciprocal of the first element, with all other elements being 0.

4. The method for optimizing the layout of measuring points in a substation grounding grid according to claim 1, characterized in that, In step 2, the measurement point set is {1,2,L,…,n}.

5. The method for optimizing the layout of measuring points in a substation grounding grid according to claim 1, characterized in that, In step 3, step 3 includes: (1) Based on the measurement point set, arbitrarily select a reference node and generate the current vector. ; (2) Calculate the voltage matrix of the grounding grid nodes ,in, The inverse of the nodal admittance matrix is... For the injected current matrix; (3) Calculate the sensitivity between each node and each branch to obtain the measurement matrix of the grounding grid. ; (4) Calculate the measurement matrix Column correlation coefficient .

6. The method for optimizing the layout of measuring points in a substation grounding grid according to claim 5, characterized in that, In step 3, , Where r is the number of measurement nodes in the selected set of measurement points, and n is the number of nodes. This represents the element in the i-th row and j-th column of the current vector. The specified injection DC current.

7. The method for optimizing the layout of measuring points in a substation grounding grid according to claim 5, characterized in that, In step 3, sensitivity ,in, .

8. The method for optimizing the layout of measuring points in a substation grounding grid according to claim 5, characterized in that, In step 3, the measurement matrix .

9. The method for optimizing the layout of measuring points in a substation grounding grid according to claim 5, characterized in that, In step 3, the correlation coefficients are listed. , express The kth column, This represents the inner product of the k-th and j-th columns. Represents the magnitude of a vector.

10. The method for optimizing the layout of measuring points in a substation grounding grid according to claim 1, characterized in that, In step 5, step 5 includes: (1) Remove one measurement point from the measurement point set in sequence to obtain a new measurement point set; (2) Calculate the column correlation coefficients of the new measurement matrix sequentially according to the method in step 3; (3) Find the column with the smallest increase in correlation coefficient. That is, the set of measurement points, return to step 3.

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