A method and system for fast reconfiguration of grounding grid topology

Abstract

The application discloses a grounding net topology structure quick reconstruction method and system. In view of problems of large area of a transformer substation, complex grounding net structure and the like, the application adopts a grounding net topology structure quick reconstruction method and system based on a combination of a "circumferential method" and a "paving method" of a magnetic field differential method; wherein, the "circumferential method" is used for detecting a trend of a grounding net branch near a down lead, so that a main net conductor of the grounding net is positioned under the condition that no other known branch exists; the "paving method" uses a "node searching" method to replace a "branch searching" method in related research, and uses a pair of nodes to determine an existing grounding net branch. The whole process of the application is simple in measurement operation and small in measurement data amount.

Description

Technical Field

[0001] This invention belongs to the field of substation grounding grid technology, and relates to a method and system for rapid reconstruction of grounding grid topology, particularly a method and system for reconstructing grounding grid topology based on magnetic field differential method combined with "circular method + paving method". Background Technology

[0002] As a crucial guarantee for the safe, reliable, and stable operation of a power system, the grounding grid is essential. When its performance deteriorates and it fails to quickly conduct lightning strikes or large short-circuit currents to the ground, voltage backflash can occur, severely endangering the electrical equipment and personnel safety of the substation. Therefore, regularly monitoring the grounding performance of the substation's grounding grid is a vital task in substation safety inspections.

[0003] In my country, galvanized flat steel with specifications of 5mm×50mm and 6mm×60mm is the primary choice for conductor materials in large grounding grids of substations; for transmission lines, round steel with a diameter of 10-20mm is commonly used. Grounding grids laid using flat or round steel are generally rectangular meshes, laid at a depth of 0.6m-2m underground, and the area of ​​the grounding grid is generally the same as the construction area of ​​the substation or power plant. Due to the complex soil environment, after the grounding grid conductors have been buried underground for a long time, the metal will corrode in the soil, generally through electrochemical corrosion.

[0004] When the conductors of a grounding grid corrode, their cross-sectional area decreases, leading to increased grounding resistance and reduced grounding performance. In extreme cases, this can cause conductor breakage, rendering the grounding grid ineffective in protecting electrical equipment and personnel, posing a serious accident threat. Furthermore, since the grounding grid is laid underground using welded galvanized flat steel, negligence during construction can result in incomplete or missed welds, causing corrosion and failure at the weld points, leading to poor electrical connections and affecting the grounding grid's performance. Substation power outages due to substandard grounding grid performance are also frequent occurrences.

[0005] To more clearly understand the performance of the grounding grid, a hidden project, relevant regulations have relatively detailed provisions on the inspection of the grounding grid status of the power system. According to the requirements of DL / T 596-2005 "Regulations for Preventive Tests of Electric Equipment" for grounding equipment of various types of substations: 1) The detection interval of the grounding resistance of various electric equipment shall not exceed 6 years. Considering that seasonal changes will affect the soil resistivity, the grounding resistance below 0.5Ω is qualified; 2) The test period of the conduction resistance between the down-lead of the electric equipment and the grounding grid shall not exceed 3 years; 3) When the substation has been operating for more than 10 years and above, it is necessary to conduct sampling excavation of the grounding grid. Randomly select 5-8 points of the grounding grid for excavation inspection according to the on-site situation, and observe the corrosion of the conductor to judge whether it is necessary to increase the number of excavation points or expand the excavation area. However, according to the current maintenance methods, there are the following problems in actual projects: 1) According to relevant statistical data, there are approximately 10,000 substations in the country that have been operating for more than ten years and need to conduct excavation inspection of the grounding grid, which will bring heavy work pressure to the power maintenance department and high economic costs. 2) The typical sampling excavation process needs to select excavation points according to the design drawings of the grounding grid. However, for some substations, especially the old substations built more than 15 years ago, there are problems with the loss of grounding grid drawings. In addition, for the modified grounding grid, there is a common phenomenon that the drawings are not updated or the modification plan is not recorded. There are also situations where the actual buried positions of some main grounding grid conductors are inconsistent with the design plan or have large errors. The problem of unknown conductor positions and burial depths caused by the above situations brings the problem of "not being able to dig" to the sampling excavation project. 3) Relevant scientific research institutions have carried out a lot of research on the corrosion diagnosis of the grounding grid and achieved some results. Among them, new technologies related to accurate corrosion diagnosis, especially the local corrosion point positioning technology that the operation and maintenance department is more concerned about, generally need to be carried out under the condition of known accurate buried positions or topological structures of the grounding grid conductors. Therefore, problems such as the long-term loss of drawings or the inconsistency between the drawings and the actual situation also hinder the application and promotion of the non-excavation diagnosis technology of the grounding grid; 4) For the grounding grid with serious corrosion, it is necessary to carry out the grounding grid transformation work. According to relevant research, the formulation of the transformation plan needs to be calculated and verified to achieve optimized design, and this process also depends on the topological structure and attribute parameters of the existing grounding grid.

[0006] Therefore, researching the conductor positioning and topological structure reconstruction technology of the grounding grid is a necessary means to achieve lean management of the grounding grid. This technology can provide point selection guidance for traditional excavation-type detection methods and also provide strong support for non-excavation local corrosion positioning technology. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a method for rapid reconstruction of the grounding grid topology for the grounding grid topology to be tested in actual engineering, so as to quickly and efficiently determine the grounding grid topology.

[0008] To achieve the above objectives, the present invention provides a technical solution as follows: a method for rapid reconfiguration of grounding grid topology, comprising:

[0009] Step 101, use the circular method and differential method to detect the initial conductor: In the absence of any unknown grounding conductor location, first determine the measurement starting point, select a grounding down conductor near the corner or edge of the substation, and use the grounding down conductor as the center to measure the magnetic field distribution along the circle with a radius of 1 meter and 2 meters respectively. The conductor location is detected by the differential method, and the conductor direction is detected by the circular method.

[0010] Step 102: Measure the magnetic field distribution using a grounding grid topology detection device;

[0011] Step 103: Perform higher-order differentiation on the magnetic field distribution curve measured by the grounding grid topology detection device. The peak point corresponding to the differential curve is the conductor position. At the same time, use the side peak characteristics of the higher-order differential function to determine the conductor burial depth.

[0012] Step 104: When using the circular method to detect the conductor's direction, select the two peak points that are closest to each other measured by the double circles and connect them into a line. Select a straight line with an angle of approximately 90° between the two lines as the two initial conductors. These two straight lines are the x-axis and y-axis, respectively. Establish a rectangular coordinate system with the intersection of the two lines as the origin.

[0013] Step 105: Establish an observation line along the x-axis in the established rectangular coordinate system, use a grounding grid topology detection device to measure the magnetic field components along the line, and determine the longitudinal conductor distribution based on the peak position after differentiation of the x-axis observation line according to the magnetic field differential method position detection principle described in step 103. Arrange 1-3 sets of magnetic field observation lines parallel to the x-axis and 3-5m away from the x-axis for verification measurement.

[0014] Step 106: After determining the part of the grounding grid topology that is parallel to the y-axis of the rectangular coordinate system established in step 104, repeat step 105 in the y-axis direction of the rectangular coordinate system to obtain the part of the grounding grid topology that is parallel to the x-axis, i.e., the distribution of transverse conductors, thereby drawing the rough topology of the entire grounding grid.

[0015] Step 107: Further refine the rough topology of the grounding grid;

[0016] Step 108: Determine the grounding grid topology diagram based on the paired node positions.

[0017] Furthermore, in step 103, the higher-order differential step is as follows: According to Ampere's circuital law, the magnetic induction intensity B generated by the current-carrying conductor at point P, parallel to the ground, is... y (y) is:

[0018]

[0019] in, h represents the burial depth of the grounding grid branch, y represents the offset, L1 represents the length of one conductor, L2 represents the length of another conductor, μ represents the permeability, and I represents the conductor injection current.

[0020] Find B y The second and fourth derivatives of (y) are given, while ignoring o.

[0021]

[0022]

[0023] Higher-order differential function |B y (y)|、 and The conductor exhibits a main peak characteristic, and its coordinates are used to determine the conductor's location.

[0024] Furthermore, in step 103, the burial depth of the conductor is determined using the side-peak characteristics of the higher-order differential function:

[0025] Let the shape function The peak distance between the main peak and the side peak is L y2 L y4 Find B y The third and fifth derivatives of (y), while neglecting o. get:

[0026]

[0027]

[0028] make and We can obtain: L y2 ≈h,

[0029] The above formula represents the shape function The peak distance between the main peak and the side peak is L y2 L y4 The relationship between the grounding grid branch burial depth h and the grounding grid branch burial depth is determined by solving the shape function. or The peak distance L between the main peak and the side peaks y2 or Ly4 The burial depth h of the grounding grid branch is obtained directly.

[0030] Furthermore, the specific details of the rough topology of the grounding grid are as follows:

[0031] For the conductors inside the coarse topology of the grounding grid obtained in step 106, a grounding grid topology detection device is used to perform refined measurements. The standard order is to measure the conductors parallel to the y-axis first, and then measure the conductors parallel to the x-axis. Based on the position of the peak value of the magnetic field differential image obtained in each measurement, the coarse topology of the grounding grid determined in step 106 is refined to obtain a refined schematic diagram of the grounding grid topology.

[0032] Furthermore, the specific details of determining the topology based on the positions of paired nodes are as follows:

[0033] For any grounding electrode branch, its nodes must appear in pairs on the adjacent vertical branches. After the node location is completed based on the initial judgment branch, it is necessary to determine whether each branch exists according to the principle of paired nodes to avoid misjudging the "T" structure caused by the initial judgment branch. At the same time, the conductor position is corrected by using the average value of the node position, and finally an accurate schematic diagram of the grounding grid topology is obtained.

[0034] Another technical solution adopted in this invention is: a rapid reconfiguration system for grounding grid topology, comprising:

[0035] The initial conductor detection unit uses the circular method and the differential method to detect the initial conductor: In the case that the location of any grounded conductor is unknown, the starting point of the measurement is first determined, and a grounding down conductor near the corner or edge of the substation is selected. With the grounding down conductor as the center, the magnetic field distribution along the circle with a radius of 1 meter and 2 meters is measured respectively. The conductor position is detected by the differential method, and the conductor direction is detected by the circular method.

[0036] The magnetic field distribution measurement unit uses a grounding grid topology detection device to measure the magnetic field distribution.

[0037] The higher-order differential unit performs higher-order differentiation on the magnetic field distribution curve measured by the grounding grid topology detection device. The peak point corresponding to the differential curve is the conductor position. At the same time, the side peak characteristics of the higher-order differential function are used to determine the conductor burial depth.

[0038] In the unit for establishing a rectangular coordinate system, when using the circular method to detect the direction of a conductor, the two peak points that are closest to each other measured by the double circles are selected and connected to form a line. The two lines with an angle of approximately 90° are selected as the two initial conductors. These two lines are the x-axis and y-axis, respectively, and the intersection of the two lines is taken as the origin to establish a rectangular coordinate system.

[0039] The conductor distribution determination unit establishes observation lines along the x-axis in the established rectangular coordinate system, uses a grounding grid topology detection device to measure the magnetic field components along the line, and determines the longitudinal conductor distribution based on the peak position after differentiation of the x-axis observation line according to the magnetic field differential method position detection principle described by the higher-order differential unit. 1-3 sets of magnetic field observation lines parallel to the x-axis and 3-5m away from the x-axis are arranged for verification measurement.

[0040] The grounding grid rough topology acquisition unit, after determining the part of the grounding grid topology parallel to the y-axis of the rectangular coordinate system established by the rectangular coordinate system establishment unit, repeats the method used by the conductor distribution determination unit in the y-axis direction of the rectangular coordinate system to obtain the part of the grounding grid topology parallel to the x-axis, i.e., the transverse conductor distribution, thereby drawing the entire grounding grid rough topology.

[0041] Grounding grid topology refinement unit, refines the coarse topology of the grounding grid;

[0042] The grounding grid topology diagram determination unit determines the grounding grid topology diagram based on the positions of paired nodes.

[0043] The beneficial technical effects of this invention are as follows:

[0044] This invention combines the "circular method" and the "paving method" based on the magnetic field differential method. Based on electromagnetic field theory, it adopts the detection principle of the magnetic field differential method, which is simple to operate and can directly draw the topology diagram of the grounding grid. Furthermore, it can be applied to the diagnosis of problems such as corrosion and fracture of the grounding grid. The results show that the missed detection rate of this invention is low and the measurement efficiency is nearly twice that of ordinary methods. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the grounding grid model in a specific embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram illustrating how a circle is approximated as a regular octagon in a specific embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram illustrating the principle of the circumferential detection method in a specific embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram showing the results of calculating the initial coordinate system using the circumferential method in a specific embodiment of the present invention;

[0049] Figure 5 This is a graph showing the magnetic field differential curves along the x-axis at the locations of some conductor nodes in a specific embodiment of the present invention;

[0050] Figure 6 This is a graph showing the magnetic field differential curves along the y-axis at the locations of some conductor nodes in a specific embodiment of the present invention;

[0051] Figure 7 This is a rough topology diagram of the grounding grid as initially determined in a specific embodiment of the present invention;

[0052] Figure 8 This is a schematic diagram of a detailed measurement position in a specific embodiment of the present invention;

[0053] Figure 9 This is a diagram showing the differential calculation results along line L3 in a specific embodiment of the present invention;

[0054] Figure 10 This is a diagram of the grounding grid topology obtained after refining the topology along line L4 in a specific embodiment of the present invention.

[0055] Figure 11 This is a diagram showing the differential calculation results along line L4 in a specific embodiment of the present invention;

[0056] Figure 12 This is a diagram showing the differential calculation results along line L5 in a specific embodiment of the present invention;

[0057] Figure 13 This is a grounding grid topology diagram obtained by refining the paving method along L4 and L5 in a specific embodiment of the present invention;

[0058] Figure 14 This is a diagram showing the results of the differential calculation along the longitudinal direction at 0m in a specific embodiment of the present invention;

[0059] Figure 15 This is a diagram showing the differential calculation results along the longitudinal direction at 5m in a specific embodiment of the present invention;

[0060] Figure 16 This is a diagram showing the results of the differential calculation along the longitudinal direction at 10m in a specific embodiment of the present invention.

[0061] Figure 17 This is a diagram showing the results of the differential calculation along the longitudinal direction at 15m in a specific embodiment of the present invention.

[0062] Figure 18 This is a diagram showing the results of the differential calculation along the longitudinal direction at 20m in a specific embodiment of the present invention;

[0063] Figure 19 The final grounding grid topology diagram is drawn for a specific embodiment of the present invention;

[0064] Figure 20 This is a flowchart of the method for rapid reconfiguration of the grounding grid topology according to the present invention;

[0065] Figure 21 This is a structural block diagram of the grounding grid topology rapid reconfiguration system of the present invention. Detailed Implementation

[0066] The technical solution of the present invention will now be clearly and thoroughly described in conjunction with the accompanying drawings.

[0067] Example 1

[0068] This embodiment provides a method for rapid reconfiguration of grounding grid topology, such as... Figure 20 As shown, it includes the following steps:

[0069] See Figure 1 The circular differential method for detecting the initial conductor: When the location of any grounding body is unknown, the starting point of the measurement must first be determined. To do this, a grounding down conductor located near a corner or edge of the substation is selected. Using this down conductor as the center, the magnetic field distribution along the circumference with radii of 1 meter and 2 meters is measured respectively. The conductor location is detected using the differential method, and the conductor's direction is detected using the circular method.

[0070] The measurement of the circular magnetic field was performed using a 0.8m long grounding grid topology detection device. This device consisted of a measuring array of eight magnetic field coils spaced 0.1m apart. The circle was approximated as a regular octagon, and the device was moved counter-clockwise for measurement. (See [link to documentation]). Figure 2 .

[0071] See Figure 3 The conductor orientation is detected using the circular method. The two peak points that are closest to each other measured by the double circle are selected and connected to form a line. The two lines with an angle of approximately 90° are selected as the two initial conductors. These two lines are the x-axis and y-axis, respectively. A rectangular coordinate system is established with the intersection of the two lines as the center.

[0072] See Figure 4 Differential position detection uses differential formulas

[0073]

[0074] The peak point corresponding to the differential curve is the conductor's position. The specific steps are as follows: Perform a higher-order differential on the magnetic field distribution curve measured by the differential position detection device. The peak point corresponding to the differential curve is the conductor's position. According to Ampere's circuital law, the magnetic induction intensity B generated by the current-carrying conductor at point P, parallel to the ground, is... y (y) is:

[0075]

[0076] in

[0077] Find the second and fourth derivatives of formula (2), while neglecting o.

[0078]

[0079]

[0080] Higher-order differential function |B y (y)|、 and It exhibits both primary peak and secondary peak characteristics. Let the shape function... The peak distance between the main peak and the side peak is L y2 L y4 .

[0081] Find the third and fifth derivatives of formula (2), while neglecting o.

[0082]

[0083]

[0084] make and We can obtain:

[0085] L y2 ≈h (7)

[0086]

[0087] The above formula concisely describes the shape function. The peak distance between the main peak and the side peak is L y2 L y4 The relationship between the grounding grid branch burial depth h and the grounding grid branch burial depth is determined by solving the shape function. or The peak distance L between the main peak and the side peaks y2 or L y4 The burial depth h of the grounding grid branch can be obtained directly.

[0088] In the established rectangular coordinate system, the magnetic field components along the x-axis were measured using a grounding grid topology detection device. The position was determined using the magnetic field differential method. The measurement results are shown in [reference needed]. Figure 5 Magnetic field survey lines parallel to the y-axis are arranged according to the peak point position of the magnetic field differential curve.

[0089] After determining the portion of the grounding grid topology parallel to the y-axis of the established rectangular coordinate system, the magnetic field differential method for position detection is repeatedly applied along the y-axis direction of the rectangular coordinate system. The measurement results are shown in [reference needed]. Figure 6 This yields the portion of the grounding grid topology parallel to the x-axis, allowing for a preliminary rough estimate of the entire grounding grid's topology. (See [link to relevant documentation]). Figure 7 .

[0090] The coarse grounding grid topology was further refined. Conductors within the initially drawn coarse grounding grid structure were measured using a grounding grid topology detection device. The standard sequence was to measure conductors parallel to the y-axis first, followed by conductors parallel to the x-axis. Based on the peak positions of the magnetic field differential images obtained from each measurement, the determined coarse network topology was refined to obtain a more accurate schematic diagram of the grounding grid topology. (See attached diagram). Figure 19 .

[0091] The methods for further refining the grounding grid topology are described in detail below:

[0092] See Figure 8 along Figure 7 Magnetic field measurements can be continued on other branches of the grounding grid to further refine and verify the distribution of each branch. For example, first determine the other nodes on the branch parallel to the x-axis at node (0, 5), i.e., measure... Figure 7 The magnetic field distribution along the straight line L3 is shown in the figure. The black line in the figure represents the current grounding grid conductor structure. L3 is on the ground surface and directly opposite the conductor below.

[0093] Differentiate the measured magnetic field and see the results. Figure 9 Therefore, it can be determined that there are five nodes on this branch, four of which are connected to... Figure 7 The initial model was consistent with the previous one, but a new branch was found at x = 5m. Therefore, in Figure 7 Add a path to the existing grounding grid topology model. See the modified model below. Figure 10 .

[0094] Similarly, measurement Figure 10 The magnetic field distributions on L4 and L5 are shown in the differential results below. Figure 11 and Figure 12 .

[0095] See Figure 11 It can be seen that there are five peaks, i.e., five branch nodes, along L4, and they correspond one-to-one with the nodes of L3. See [link / reference]. Figure 12 It can be seen that there are only three nodes along L5, so there is no conductor for the missing peak between L4 and L5, meaning there is no grounding conductor at 5m and 15m. Based on these two sets of data, the grounding network topology should be modified (see [reference needed]). Figure 13 .

[0096] contrast Figure 1 Constructing model structure and Figure 13 The model structure is currently available, and it can be seen that only one branch remains undetected. This is achieved through transverse magnetic field measurements. Figure 13The topological structure model is given, but the remaining topological structure still needs to be drawn by measuring the longitudinal magnetic field distribution. Longitudinal magnetic field measurements and differential analysis are performed at 0m, 5m, 10m, 15m, and 20m.

[0097] The differential calculation results after measuring the magnetic field distribution at 0m are shown below. Figure 14 There are four peaks, i.e. four branch nodes, along the longitudinal direction. Only the peak point at 10m is missing. Therefore, there are four conductors at 0m, 5m, 15m, and 20m, but no conductor at 10m.

[0098] The differential calculation results after measuring the magnetic field distribution at 5m are shown below. Figure 15 There are three peaks, i.e. three branch nodes, along the longitudinal direction. The peaks at 0m and 20m are missing. Therefore, there are three conductors at 5m, 10m and 15m, but no conductors at 0m and 20m.

[0099] The differential calculation results after measuring the magnetic field distribution at 10m are shown below. Figure 16 There are five peaks, i.e. five branch nodes, along the longitudinal direction. There are no missing peaks, so there are conductors at 0m, 5m, 10m, 15m, and 20m.

[0100] The differential calculation results after measuring the magnetic field distribution at 15m are shown below. Figure 17 There are four peaks, i.e. four branch nodes, along the longitudinal direction. The peak point at 0m is missing. Therefore, there are four conductors at 5m, 10m, 15m, and 20m, but no conductor at 0m.

[0101] The differential calculation results after measuring the magnetic field distribution at 20m are shown below. Figure 18 There are five peaks, i.e. five branch nodes, along the longitudinal direction. There are no missing peaks, so there are conductors at 0m, 5m, 10m, 15m, and 20m.

[0102] Example 2

[0103] This embodiment provides a system for rapid reconfiguration of grounding grid topology, such as... Figure 21 As shown, it consists of an initial conductor detection unit, a magnetic field distribution measurement unit, a higher-order differential unit, a rectangular coordinate system establishment unit, a conductor distribution determination unit, a grounding grid rough topology acquisition unit, a grounding grid topology refinement unit, and a grounding grid topology diagram determination unit.

[0104] The initial conductor detection unit uses the circular method and the differential method to detect the initial conductor: In the case that the location of any grounded conductor is unknown, the starting point of the measurement is first determined, and a grounding down conductor near the corner or edge of the substation is selected. With the grounding down conductor as the center, the magnetic field distribution along the circle with a radius of 1 meter and 2 meters is measured respectively. The conductor position is detected by the differential method, and the conductor direction is detected by the circular method.

[0105] The magnetic field distribution measurement unit uses a grounding grid topology detection device to measure the magnetic field distribution.

[0106] The higher-order differential unit performs higher-order differentiation on the magnetic field distribution curve measured by the grounding grid topology detection device. The peak point corresponding to the differential curve is the conductor position. At the same time, the side peak characteristics of the higher-order differential function are used to determine the conductor burial depth.

[0107] In the unit for establishing a rectangular coordinate system, when using the circular method to detect the direction of a conductor, the two peak points that are closest to each other measured by the double circles are selected and connected to form a line. The two lines with an angle of approximately 90° are selected as the two initial conductors. These two lines are the x-axis and y-axis, respectively, and the intersection of the two lines is taken as the origin to establish a rectangular coordinate system.

[0108] The conductor distribution determination unit establishes observation lines along the x-axis in the established rectangular coordinate system, uses a grounding grid topology detection device to measure the magnetic field components along the line, and determines the longitudinal conductor distribution based on the peak position after differentiation of the x-axis observation line according to the magnetic field differential method position detection principle described by the higher-order differential unit. 1-3 sets of magnetic field observation lines parallel to the x-axis and 3-5m away from the x-axis are arranged for verification measurement.

[0109] The grounding grid rough topology acquisition unit, after determining the part of the grounding grid topology parallel to the y-axis of the rectangular coordinate system established by the rectangular coordinate system establishment unit, repeats the method used by the conductor distribution determination unit in the y-axis direction of the rectangular coordinate system to obtain the part of the grounding grid topology parallel to the x-axis, i.e., the transverse conductor distribution, thereby drawing the entire grounding grid rough topology.

[0110] Grounding grid topology refinement unit, refines the coarse topology of the grounding grid;

[0111] The grounding grid topology diagram determination unit determines the grounding grid topology diagram based on the positions of paired nodes.

[0112] In the aforementioned higher-order differential unit, the steps of higher-order differentiation are as follows: According to Ampere's circuital law, the magnetic induction intensity B generated by the current-carrying conductor at point P, parallel to the ground, is... y (y) is:

[0113]

[0114] in, h represents the burial depth of the grounding grid branch, y represents the offset, L1 represents the length of one conductor, L2 represents the length of another conductor, μ represents the permeability, and I represents the conductor injection current.

[0115] Find B y The second and fourth derivatives of (y) are given, while ignoring o.

[0116]

[0117]

[0118] Higher-order differential function |B y (y)|、 and The conductor exhibits a main peak characteristic; its coordinates are used to determine the conductor's location. The burial depth is determined using the side peak characteristics of higher-order differential functions.

[0119] Let the shape function The peak distance between the main peak and the side peak is L y2 L y4 Find B y The third and fifth derivatives of (y), while neglecting o. get:

[0120]

[0121]

[0122] make and We can obtain: L y2 ≈h,

[0123] The above formula represents the shape function The peak distance between the main peak and the side peak is L y2 L y4 The relationship between the grounding grid branch burial depth h and the grounding grid branch burial depth is determined by solving the shape function. or The peak distance L between the main peak and the side peaks y2 or L y4 The burial depth h of the grounding grid branch is obtained directly.

[0124] The specific details of the grounding grid topology refinement unit are as follows:

[0125] For the conductors inside the coarse topology of the grounding grid obtained by the grounding grid coarse topology acquisition unit, a grounding grid topology detection device is used to perform refined measurements. The standard order is to measure the conductors parallel to the y-axis first, and then the conductors parallel to the x-axis. Based on the position of the peak value of the magnetic field differential image obtained from each measurement, the coarse topology of the grounding grid determined by the grounding grid coarse topology acquisition unit is refined to obtain a refined grounding grid topology schematic diagram.

[0126] The specific details of the unit for determining the grounding grid topology diagram are as follows:

[0127] For any grounding electrode branch, its nodes must appear in pairs on the adjacent vertical branches. After the node location is completed based on the initial judgment branch, it is necessary to determine whether each branch exists according to the principle of paired nodes to avoid misjudging the "T" structure caused by the initial judgment branch. At the same time, the conductor position is corrected by using the average value of the node position, and finally an accurate schematic diagram of the grounding grid topology is obtained.

[0128] The above embodiments should be understood as illustrative only and not as limiting the scope of protection of the present invention. After reading the description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention's method for rapid reconfiguration of grounding grid topology.

Claims

1. A method for rapid reconstructing of grounding grid topology, characterized in that, include: Step 101, use the circular method and differential method to detect the initial conductor: In the absence of any unknown grounding conductor location, first determine the measurement starting point, select a grounding down conductor near the corner or edge of the substation, and use the grounding down conductor as the center to measure the magnetic field distribution along the circle with a radius of 1 meter and 2 meters respectively. The conductor location is detected by the differential method, and the conductor direction is detected by the circular method. Step 102: Measure the magnetic field distribution using a grounding grid topology detection device; Step 103: Perform higher-order differentiation on the magnetic field distribution curve measured by the grounding grid topology detection device. The peak point corresponding to the differential curve is the conductor position. At the same time, use the side peak characteristics of the higher-order differential function to determine the conductor burial depth. Step 104: When using the circular method to detect the conductor's direction, select the two peak points that are closest to each other measured by the double circles and connect them into a line. Select a straight line with an angle of approximately 90° between the two lines as the two initial conductors. These two straight lines are the x-axis and y-axis, respectively. Establish a rectangular coordinate system with the intersection of the two lines as the origin. Step 105: Establish an observation line along the x-axis in the established rectangular coordinate system, use a grounding grid topology detection device to measure the magnetic field components along the line, and determine the longitudinal conductor distribution based on the peak position after differentiation of the x-axis observation line according to the magnetic field differential method position detection principle described in step 103. Arrange 1-3 sets of magnetic field observation lines parallel to the x-axis and 3-5m away from the x-axis for verification measurement. Step 106: After determining the part of the grounding grid topology that is parallel to the y-axis of the rectangular coordinate system established in step 104, repeat step 105 in the y-axis direction of the rectangular coordinate system to obtain the part of the grounding grid topology that is parallel to the x-axis, that is, to obtain the distribution of the transverse conductors, thereby drawing the rough topology of the entire grounding grid. Step 107: Refine the rough topology of the grounding grid; Step 108: Determine the grounding grid topology diagram based on the paired node positions; In step 103, the higher-order differential step is as follows: According to Ampere's circuital law, the magnetic induction intensity B generated by the current-carrying conductor at point P, parallel to the ground, is... y (y) is: in, h represents the burial depth of the grounding grid branch, y represents the offset, L1 represents the length of one conductor, L2 represents the length of another conductor, μ represents the permeability, and I represents the conductor injection current. Find B y The second and fourth derivatives of (y) are ignored. Higher-order differential function |B y (y)|、 and The conductor exhibits a main peak characteristic, and its location can be determined using the coordinates of the main peak. Determining conductor burial depth using the side-peak characteristics of higher-order differential functions: Let the shape function The peak distance between the main peak and the side peak is L y2 L y4 Find B y The third and fifth derivatives of (y), while neglecting the third and fifth derivatives of (y), get: make and We can obtain: L y2 ≈h, The above formula represents the shape function The peak distance L between the main peak and the side peaks y2 L y4 The relationship between the grounding grid branch burial depth h and the grounding grid branch burial depth is determined by solving the shape function. or The peak distance L between the main peak and the side peaks y2 or L y4 The burial depth h of the grounding grid branch is obtained directly.

2. The method for rapid reconfiguration of grounding grid topology according to claim 1, characterized in that, The detailed content of the rough topology of the grounding grid is as follows: For the conductors inside the coarse topology of the grounding grid obtained in step 106, a grounding grid topology detection device is used to perform refined measurements. The standard order is to measure the conductors parallel to the y-axis first, and then measure the conductors parallel to the x-axis. Based on the position of the peak value of the magnetic field differential image obtained in each measurement, the coarse topology of the grounding grid determined in step 106 is refined to obtain a refined schematic diagram of the grounding grid topology.

3. The method for rapid reconfiguration of grounding grid topology according to claim 1, characterized in that, The specific details of determining the topology based on the positions of paired nodes are as follows: For any grounding electrode branch, its nodes must appear in pairs on the adjacent vertical branches. After the node location is completed based on the initial judgment branch, it is necessary to determine whether each branch exists according to the principle of paired nodes to avoid misjudging the "T" structure caused by the initial judgment branch. At the same time, the conductor position is corrected by using the average value of the node position, and finally an accurate schematic diagram of the grounding grid topology is obtained.

4. A rapid reconfiguration system for grounding grid topology, characterized in that, include: The initial conductor detection unit uses the circular method and the differential method to detect the initial conductor: In the case that the location of any grounded conductor is unknown, the starting point of the measurement is first determined, and a grounding down conductor near the corner or edge of the substation is selected. With the grounding down conductor as the center, the magnetic field distribution along the circle with a radius of 1 meter and 2 meters is measured respectively. The conductor position is detected by the differential method, and the conductor direction is detected by the circular method. The magnetic field distribution measurement unit uses a grounding grid topology detection device to measure the magnetic field distribution. The higher-order differential unit performs higher-order differentiation on the magnetic field distribution curve measured by the grounding grid topology detection device. The peak point corresponding to the differential curve is the conductor position. At the same time, the side peak characteristics of the higher-order differential function are used to determine the conductor burial depth. In the unit for establishing a rectangular coordinate system, when using the circular method to detect the direction of a conductor, the two peak points that are closest to each other measured by the double circles are selected and connected to form a line. The two lines with an angle of approximately 90° are selected as the two initial conductors. These two lines are the x-axis and y-axis, respectively, and the intersection of the two lines is taken as the origin to establish a rectangular coordinate system. The conductor distribution determination unit establishes observation lines along the x-axis in the established rectangular coordinate system, uses a grounding grid topology detection device to measure the magnetic field components along the line, and determines the longitudinal conductor distribution based on the peak position after differentiation of the x-axis observation line according to the magnetic field differential method position detection principle described by the higher-order differential unit. 1-3 sets of magnetic field observation lines parallel to the x-axis and 3-5m away from the x-axis are arranged for verification measurement. The grounding grid rough topology acquisition unit, after determining the part of the grounding grid topology parallel to the y-axis of the rectangular coordinate system established by the rectangular coordinate system establishment unit, repeats the method used by the conductor distribution determination unit in the y-axis direction of the rectangular coordinate system to obtain the part of the grounding grid topology parallel to the x-axis, i.e., the transverse conductor distribution, thereby drawing the entire grounding grid rough topology. Grounding grid topology refinement unit, refines the coarse topology of the grounding grid; The grounding grid topology diagram determination unit determines the grounding grid topology diagram based on the positions of paired nodes. In the aforementioned higher-order differential unit, the steps of higher-order differentiation are as follows: According to Ampere's circuital law, the magnetic induction intensity B generated by the current-carrying conductor at point P, parallel to the ground, is... y (y) is: in, h represents the burial depth of the grounding grid branch, y represents the offset, L1 represents the length of one conductor, L2 represents the length of another conductor, μ represents the permeability, and I represents the conductor injection current. Find B y The second and fourth derivatives of (y) are ignored. Higher-order differential function |B y (y)|、 and The conductor exhibits a main peak characteristic, and its location can be determined using the coordinates of the main peak. In the aforementioned higher-order differential unit, the conductor burial depth is determined using the side-peak characteristics of the higher-order differential function: Let the shape function The peak distance between the main peak and the side peak is L y2 L y4 Find B y The third and fifth derivatives of (y), while neglecting the third and fifth derivatives of (y), get: make and We can obtain: L y2 ≈h, The above formula represents the shape function The peak distance L between the main peak and the side peaks y2 L y4 The relationship between the grounding grid branch burial depth h and the grounding grid branch burial depth is determined by solving the shape function. or The peak distance L between the main peak and the side peaks y2 or L y4 The burial depth h of the grounding grid branch is obtained directly.

5. A rapid reconfiguration system for grounding grid topology according to claim 4, characterized in that, The specific details of the grounding grid topology refinement unit are as follows: For the conductors inside the coarse topology of the grounding grid obtained by the grounding grid coarse topology acquisition unit, a grounding grid topology detection device is used to perform refined measurements. The standard order is to measure the conductors parallel to the y-axis first, and then the conductors parallel to the x-axis. Based on the position of the peak value of the magnetic field differential image obtained from each measurement, the coarse topology of the grounding grid determined by the grounding grid coarse topology acquisition unit is refined to obtain a refined grounding grid topology schematic diagram.

6. The grounding grid topology rapid reconfiguration system according to claim 4, characterized in that, The specific details of the unit for determining the grounding grid topology diagram are as follows: For any grounding electrode branch, its nodes must appear in pairs on the adjacent vertical branches. After the node location is completed based on the initial judgment branch, it is necessary to determine whether each branch exists according to the principle of paired nodes to avoid misjudging the "T" structure caused by the initial judgment branch. At the same time, the conductor position is corrected by using the average value of the node position, and finally an accurate schematic diagram of the grounding grid topology is obtained.

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