A method and system for dynamic assessment of a power plant grounding short circuit transfer potential

Abstract

The application relates to the technical field of substation grounding grid evaluation, and provides a power station grounding short-circuit transfer potential dynamic evaluation method and system, which comprises the following steps: adopting the Wenner four-electrode method to measure the apparent resistivity of soil, and constructing an apparent resistivity-depth change curve; adopting an inversion algorithm, combining an analytical kernel function and a Bessel function expansion, inversely deducing the resistivity and thickness of each layer of soil, and obtaining soil layering parameters of a multilayer and non-uniform structure; obtaining a short-circuit current and a grounding grid structure, and the obtained soil layering parameters; and adopting a coupling simulation analysis of a mixed method of a finite element method and a moment method to obtain the grounding short-circuit transfer potential of the grounding grid of the power station to be evaluated. The application constructs a real soil model by combining the Wenner four-electrode method measurement and the inversion algorithm, and introduces the coupling simulation of the finite element and the moment method, so that the grounding short-circuit transfer potential can be accurately evaluated, and the prediction accuracy and system safety under complex geological conditions can be significantly improved.

Description

Technical Field

[0001] This invention relates to the technical field of substation grounding grid assessment, specifically to a method and system for dynamic assessment of grounding short-circuit transfer potential in power plants. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] In power systems, when a ground fault current flows through a grounding device, a potential difference is created between the grounding device and the surrounding ground, known as a transfer potential. This potential difference can pose a serious threat to surrounding equipment and personal safety. With the continuous development of power systems, especially the widespread adoption of ultra-high voltage direct current transmission systems, short-circuit currents have increased significantly, posing greater technical challenges to grounding systems. The problems of equipment damage and electric shock risks caused by transfer potentials are becoming increasingly prominent.

[0004] Existing methods for calculating ground fault potential in power plants have certain limitations. Traditional methods are mostly based on simple formula derivations, such as Ug=IR, and assume the soil is a homogeneous medium. This can easily lead to significant errors in areas with high resistivity or complex soil structures, with calculation deviations potentially exceeding 30%. Furthermore, existing modeling methods largely rely on average resistivity parameters and use single-layer or simplified layered soil models for approximate calculations, which fails to meet the demands for high-precision simulation modeling and limits their applicability in complex engineering environments. Simultaneously, current mitigation measures, such as optimizing the grounding grid structure or applying new grounding materials, are still insufficient to completely eliminate the risks posed by potential transfer. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a dynamic assessment method and system for grounding short-circuit transfer potential in power plants. By combining the Winner four-electrode method with an inversion algorithm to construct a realistic soil model, and introducing coupled simulation of finite element method and method of moments, the method accurately assesses the grounding short-circuit transfer potential, significantly improving prediction accuracy and system safety under complex geological conditions. By calculating the potential changes caused by grounding short circuits, the method assesses and reduces the impact on equipment and facilities within the power plant, thereby achieving equipment protection within the power plant.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: One or more embodiments provide a method for dynamic assessment of ground fault transfer potential in a power plant, comprising the following steps: For the power plant to be evaluated, the apparent resistivity of the soil was measured using the Wenner quadrupole method, and the apparent resistivity-depth variation curve was constructed. For the fitted apparent resistivity-depth variation curve, an inversion algorithm is used, combined with analytical kernel function and Bessel function expansion, to inversely deduce the resistivity and thickness of each soil layer, and obtain the soil stratification parameters of multi-layered, non-uniform structure. By acquiring the short-circuit current, grounding grid structure, and soil stratification parameters, a coupled simulation analysis combining the finite element method and the method of moments is used to obtain the grounding short-circuit transfer potential of the grounding grid of the power station to be evaluated.

[0007] One or more embodiments provide a dynamic assessment system for ground fault transfer potential in a power plant, comprising: The module is configured to measure the apparent resistivity of the soil using the Wenner quadrupole method for the power plant to be evaluated, and to construct an apparent resistivity-depth variation curve. The inversion module is configured to use an inversion algorithm to deduce the resistivity and thickness of each soil layer by combining analytical kernel function and Bessel function expansion for the fitted apparent resistivity-depth variation curve, thus obtaining the soil stratification parameters of multi-layered, non-uniform structure. The coupled solution module is configured to obtain the short-circuit current, grounding grid structure, and soil stratification parameters. It uses a coupled simulation analysis combining the finite element method and the method of moments to obtain the grounding short-circuit transfer potential of the grounding grid of the power plant to be evaluated.

[0008] An electronic device includes a memory and a processor, as well as computer instructions stored in the memory and running on the processor. When the processor executes the computer instructions, it performs the steps in the above-described method for dynamic evaluation of grounding short-circuit transfer potential in a power plant.

[0009] A computer-readable storage medium for storing computer instructions, which, when executed by a processor, complete the steps in the above-described method for dynamic evaluation of ground fault transfer potential in a power plant.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs the Winner quadrupole method combined with an inversion algorithm to accurately obtain non-uniform soil structure parameters, significantly improving the realism and simulation accuracy of the soil model. The coupled simulation method of finite element method and method of moments comprehensively considers the electromagnetic response of multi-layered soils and the influence of complex grounding grid structures, effectively improving the accuracy of transfer potential prediction. The entire evaluation process possesses good versatility and scalability, applicable to power plants with different geological environments and various grounding structures. The evaluation results can provide a scientific basis for subsequent grounding system optimization design and safety protection measures, improving the safety and reliability of system operation.

[0011] The advantages of the present invention, as well as its additional advantages, will be described in detail in the following specific embodiments. Attached Figure Description

[0012] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute a limitation thereof.

[0013] Figure 1 This is a schematic diagram of the Wenner quadrupole method for measuring soil resistivity in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of the horizontally layered soil physical model of Embodiment 1 of the present invention; Figure 3 This is a resistivity ρ(a) curve of Embodiment 1 of the present invention; Figure 4 This is a flowchart of the dynamic evaluation method for ground fault transfer potential in power plants according to Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the power plant grounding grid and soil stratification model according to Embodiment 1 of the present invention; Figure 6 This is a surface potential map obtained from simulation analysis of Embodiment 1 of the present invention; Figure 7 This is the step voltage diagram obtained from the simulation analysis of Embodiment 1 of the present invention. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0016] It should be noted that the terminology used herein is for describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. It should be noted that, without conflict, the various embodiments and features within those embodiments can be combined with each other. The embodiments will now be described in detail with reference to the accompanying drawings.

[0017] Example 1 In one or more of the technical solutions disclosed in the embodiments, such as Figures 1 to 7 As shown, a method for dynamic assessment of ground fault transfer potential in power plants includes the following steps: Step 1: For the power plant to be evaluated, the apparent resistivity of the soil is measured using the Wenner quadrupole method, and the apparent resistivity-depth variation curve is constructed. Step 2: For the fitted apparent resistivity-depth variation curve, the inversion algorithm is used, combined with the analytical kernel function and Bessel function expansion, to deduce the resistivity and thickness of each soil layer, and obtain the soil stratification parameters of multi-layered, non-uniform structure. Step 3: Obtain the short-circuit current and grounding grid structure, as well as the obtained soil stratification parameters. Use a coupled simulation analysis combining the finite element method (FEM) and the method of moments (MoM) to obtain the grounding short-circuit transfer potential of the grounding grid of the power station to be evaluated. The method in this embodiment is based on soil resistivity testing theory and electromagnetic field numerical calculation technology in electrical engineering. First, the apparent resistivity at different electrode spacings is measured using the Winner quadrupole method to obtain a set of data representing the longitudinal resistivity distribution of the soil. Next, using an inversion algorithm, the measurement results are fitted into a resistivity-depth curve, and mathematical modeling is performed using analytical kernel functions and Bessel function expansions to extract the resistivity and thickness information of each soil layer, thus establishing a multi-layered, non-uniform soil model. Based on this, combined with the actual grounding grid structure parameters and the short-circuit current input conditions during a ground fault, a coupled simulation method of finite element method (FEM) and method of moments (MoM) is used. Taking into account soil stratification, grounding grid potential distribution, and electromagnetic coupling effects, the transfer potential at any location on the ground during a ground fault is calculated, enabling a dynamic assessment of the safety performance of the power station's grounding system.

[0018] Compared to traditional methods based on the assumption of uniform soil and simplified formula derivation, this embodiment uses the Winner four-pole method combined with an inversion algorithm, which can accurately obtain the structural parameters of non-uniform soil, significantly improving the realism and simulation accuracy of the soil model. The coupled simulation method of finite element method and method of moments can comprehensively consider the influence of multi-layered soil electromagnetic response and complex grounding grid structure, effectively improving the accuracy of transfer potential prediction. The entire evaluation process has good versatility and scalability, applicable to power plants with different geological environments and various grounding structures. The evaluation results can provide a scientific basis for subsequent grounding system optimization design and safety protection measures, improving the safety and reliability of system operation.

[0019] In this embodiment, the current distribution and potential transfer of the grounding system under short-circuit faults are estimated by combining the advantages of the finite element method in handling complex geometries and dielectric distributions with the strength of the method of moments in handling open area radiation problems. This allows for a more accurate simulation of the electromagnetic characteristics of the power plant grounding system under short-circuit faults, thus providing a reliable data foundation for subsequent dynamic evaluation.

[0020] To analyze the measurement data, it is necessary to first obtain the analytical relationship between the apparent resistivity and the distance between measuring electrodes for multi-layered soil conditions. In step 1, based on the Winner four-electrode method measurement data, a soil resistivity model that includes at least the surface, intermediate, and deep layers is established, i.e., the apparent resistivity-depth variation curve.

[0021] Specifically, the relationship between apparent soil resistivity and the distance between measuring electrodes was measured using the equidistant Wenner four-electrode method, as shown in the figure. Figure 1 As shown. Four electrodes are arranged at equal intervals along a straight line, and are denoted as A, C, D, and B respectively. The distance between the electrodes is 'a', that is, the distance between AC, CD, and DB is 'a'. A and B are current electrodes (I+, I-), used to inject current into the ground; C and D are voltage terminals (V+, V-), used to measure voltage difference.

[0022] When the interelectrode spacing is a, the potential difference between points C and D when measuring soil resistivity using the Wenner method is: (1); Therefore, the apparent resistivity measured by the current-voltage method at a distance of a is... The formula for measuring apparent resistivity is: (2); By changing the interpolar spacing 'a', the corresponding... The value can be obtained Curve. Different points 'a' on the curve. The resistivity value, to a certain extent, represents the overall situation of the stratum resistivity at a corresponding depth. By combining multi-point measurements and curve inversion analysis, the corresponding subsurface layer structure and parameters of the measured area can be further obtained. This method is simple to implement, and surface resistivity testing can indirectly reveal the structural changes in deep soil layers. It has good applicability and reference value, especially under the condition of a relatively homogeneous single-layer medium in the shallow soil.

[0023] The key to analyzing soil stratification parameters using apparent resistivity curves is to link apparent resistivity with soil stratification parameters. As can be seen from equation (2), apparent resistivity is related to the measured potential difference, which can be obtained by solving for the current source at the current electrode on the surface of the soil in multi-layered soil. That is, starting from the point current source on the surface, an expression for the electric field distribution along the surface is obtained by defining apparent resistivity.

[0024] In step 2, solving for the soil stratification structure parameters is actually a mathematical inversion problem; For the fitted apparent resistivity-depth variation curve, an inversion algorithm is used, combining analytical kernel function and Bessel function expansion, to deduce the resistivity and thickness of each soil layer, thus obtaining the stratification parameters of multi-layered, non-uniform soil structures. The method includes the following steps: Step 21: Assuming the ground surface is an infinitely large horizontal plane and the underground consists of multiple layers of horizontally homogeneous soil, construct a layered soil physical model, with each layer having the following parameters: Figure 2 As shown, assume the ground is an infinitely large plane, and there are n horizontally layered strata below the ground. The resistivity of each layer is ρ1, ρ2, ..., ρn, and the thickness is h1, h2, ..., hn. The distance from the bottom of each layer to the ground is H1, H2, ..., Hn-1, Hn=∞.

[0025] Step 22: Based on the constructed layered soil physical model, the Laplace equation is used to establish the governing equations for the potential V at each spatial location in the cylindrical coordinate system. A point current source is placed at point O, injecting a current I into the ground. At lower frequencies, the distribution of a constant current in space is stable, meaning it does not change with time. Like an electrostatic field, it is a potential field. Therefore, except for point O where the point source is located, the potential V at all other spatial locations should satisfy Laplace's equation: (3); Considering the infinite extensibility of a horizontal surface, such as Figure 2 As shown, with the origin at point O and the Z-axis pointing vertically downwards, due to the symmetry in the horizontal direction, the potential distribution is independent of the direction angle φ. In the cylindrical coordinate system (r, φ, z), the potential distribution satisfies the following Laplace equation: (4); Step 23: Set the boundary conditions for the governing equation of potential V, including interlayer boundary continuity conditions, surface boundary conditions, and infinite boundary conditions; 1) Interlayer boundary continuity condition, i.e., the potential is equal and the current density is continuous at the interface z=Hi: (5); 2) Boundary condition at infinity, i.e., the potential is zero as z → ∞: (6); 3) Surface boundary conditions, i.e., the normal component of the current density at any point on the Earth's surface other than the origin is 0: (7); Step 24: Using the method of separation of variables and the expansion of Bessel functions, the governing equation of potential V is decomposed to obtain the potential expressions of each soil layer, and the unknown coefficients in the potential expressions are solved based on the set boundary conditions. Using the method of separation of variables and boundary conditions, the potential expression in the first layer can be obtained as follows: (8); in, For a Bessel function of the first kind, the zeroth order. and Let λ be a function of the undetermined integration variable λ, and the two are equal.

[0026] The potential expression from the second layer down to the (n-1)th layer is: (9); The potential expression in the nth layer is: (10); and These 2(n–1) variables can be solved using the interface condition equation, which is as follows: (11); The potential expression of a point current source at any point on the Earth's surface is: (12); in, Kernel functions related to soil stratification parameters: (13); The kernel functions for different layering cases are derived as shown in Table 1; Table 1. Kernel functions under different levels of hierarchical structure;

[0027] Step 25: Based on the potential expression of a point current source at any point on the earth's surface related to soil stratification parameters, and the apparent resistivity measurement formula, obtain the relationship between the apparent soil resistivity measurement value and the soil stratification parameters. Step 26: Obtain the measured apparent resistivity data, solve the relationship between the measured apparent soil resistivity and the soil stratification parameters, and obtain the soil stratification parameters. Specifically, by substituting the surface point current source calculation formula (Formula 12) related to soil stratification parameters into Formula (2), the relationship between the apparent soil resistivity measurement value and the soil stratification parameters can be obtained. If the measurement electrode spacing a is changed and a series of apparent resistivity data are measured, a series of equations can be obtained. Solving this set of equations can yield the soil stratification parameters. Specifically, soil stratification parameters include the number of horizontal soil layers, the resistivity of each soil layer, and the thickness of each soil layer (unit: m); these data are very important for analyzing the performance of the grounding grid.

[0028] This embodiment constructs an apparent resistivity-depth variation curve based on the apparent resistivity measurement data of the Winner quadrupole method at different pole spacings, and uses a multi-layer soil inversion algorithm (combining analytical kernel function and Bessel function expansion) to deduce the resistivity and thickness of each soil layer, thus obtaining a multi-layer, non-uniform soil electrical model, providing high-precision input conditions for finite element / method of moments coupled simulation.

[0029] In step 3, a coupled and fused approach combining the finite element method (FEM) and the method of moments (MoM) is used to calculate the transfer point location; A method for obtaining the short-circuit current, grounding grid structure, and soil stratification parameters, and using a coupled simulation analysis combining the finite element method (FEM) and the method of moments (MoM) to determine the grounding short-circuit transfer potential of the power plant to be evaluated, includes the following steps: Step 31: Obtain the short-circuit current, grounding grid structure, and soil stratification parameters; Step 32: Obtain the soil structure of the power plant to be evaluated and divide the area according to soil homogeneity; When the power station was built, the geology was explored, and the soil structure of the power station can be determined by consulting data; Step 33: For areas where soil uniformity is higher than the set value, the method of moments (MoM) is used for simulation analysis to obtain the grounding short-circuit transfer potential of the corresponding area of ​​the power plant to be evaluated. Step 34: For areas where the soil uniformity is lower than the set value, use the finite element method for simulation analysis to obtain the grounding short-circuit transfer potential of the corresponding area of ​​the grounding grid of the power station to be evaluated; Step 35: Starting from the point current source, calculate the transfer potential distribution of each region sequentially from the near field to the far field; generate an equivalent boundary source at the region boundary based on the point potential distribution calculated in the previous region; when calculating the next region, solve the problem by receiving the equivalent boundary source data and extending to the far field to complete the global potential field calculation. For example, the regions from the near field to the far field are O1, O2, and O3, respectively. The distribution of the ground short-circuit transfer potential in region O1 is obtained through finite element method simulation analysis. Boundary potential distributions are set at the adjacent edges of O1 and O2 as the starting conditions for the simulation calculation of the next region O2, such as the method of moments (MoM). Thus, the point distribution in region O2 is obtained. The solution is completed when the point distribution of all regions is obtained. In this embodiment, the current distribution and potential transfer of the grounding system under short-circuit faults are estimated by combining the advantages of the finite element method in handling complex geometries and dielectric distributions with the strength of the method of moments in handling open area radiation problems. This allows for a more accurate simulation of the electromagnetic characteristics of the power plant grounding system under short-circuit faults, thus providing a reliable data foundation for subsequent dynamic evaluation.

[0030] In some embodiments, the modeling for finite element method simulation analysis is as follows: The finite element method discretizes the entire computational domain into a finite number of small elements, and approximates the potential distribution within each element using an interpolation function. The computational domain includes soil, grounding grid, and air. Small elements can be tetrahedral or hexahedral. Grounding grid modeling: Conductors are simulated using three-dimensional solid units or line units.

[0031] Boundary conditions: Set an infinite boundary, such as a spherical or cubic boundary, with a potential of 0. A current excitation source can be applied (e.g., injecting a 1kA short-circuit current into a point on the grounding grid).

[0032] The calculation process for finite element method simulation analysis is as follows: Step 341, Pre-processing: Use finite element software to establish a grounding grid and soil model; Step 342, Solution and Calculation: Based on the obtained current injection values ​​and soil stratification data, the Poisson equation is solved using the Galerkin method or the weighted residual method to obtain point parameters such as surface potential distribution, step voltage, and contact voltage; an example of the simulated surface potential distribution results is shown below. Figure 6 As shown, the step voltage diagram is as follows: Figure 7 As shown; The Poisson equation is: ; Where σ is the conductivity, Let J be the electric potential, and J be the current density.

[0033] In some embodiments, the method of moments (MoM) simulation analysis: The method of moments is based on the boundary integral equation, which only requires discretizing the conductor surface and does not require modeling the entire soil domain; Grounding grid modeling: Discretize conductor surfaces using patch elements; Soil modeling: Modeling is performed as if the soil is homogeneous. If it is stratified, the complex mirror method is used for correction. This method can be extended to horizontally stratified soil, such as the Sommerfeld integral. Excitation method: Current source excitation is used, such as short-circuit current injection into a node.

[0034] The calculation process for simulation analysis using the Method of Moments (MoM) is as follows: Preprocessing: Establish a grounding grid model, and discrete conductor surfaces are triangular or quadrilateral patches; Solution calculation: Based on the obtained current injection value and soil stratification data, the established electric field integral equation (EFIE) is solved to calculate the conductor current distribution and thus obtain the surface potential; The integral equation for the electric field is: ; Where G is the Green's function and J is the surface current.

[0035] This embodiment not only integrates the finite element method and the method of moments for coupled modeling, thus balancing modeling accuracy and computational efficiency, but also proposes a layered soil modeling method based on Wenner's four-pole method measurement data, achieving a realistic inversion of non-uniform soil structures. This multi-layered structure inversion modeling method, oriented towards simulation solutions, possesses higher physical accuracy and model expressive power, and is suitable for precise calculation of transfer potentials in complex soil environments.

[0036] Example 2 Based on Example 1, this example provides a dynamic assessment system for ground fault transfer potential in power plants, comprising: The module is configured to measure the apparent resistivity of the soil using the Wenner quadrupole method for the power plant to be evaluated, and to construct an apparent resistivity-depth variation curve. The inversion module is configured to use an inversion algorithm to deduce the resistivity and thickness of each soil layer by combining analytical kernel function and Bessel function expansion for the fitted apparent resistivity-depth variation curve, thus obtaining the soil stratification parameters of multi-layered, non-uniform structure. The coupled solution module is configured to obtain the short-circuit current, grounding grid structure, and soil stratification parameters. It uses a coupled simulation analysis combining the finite element method and the method of moments to obtain the grounding short-circuit transfer potential of the grounding grid of the power plant to be evaluated.

[0037] It should be noted that each module in this embodiment corresponds one-to-one with each step in embodiment 1, and their specific implementation process is the same, so it will not be repeated here.

[0038] Example 3 Based on Embodiment 1, this embodiment provides an electronic device, including a memory and a processor, as well as computer instructions stored in the memory and running on the processor. When the computer instructions are executed by the processor, they complete the steps in the dynamic evaluation method for grounding short-circuit transfer potential of a power plant as described in Embodiment 1.

[0039] Example 4 Based on Embodiment 1, this embodiment provides a computer-readable storage medium for storing computer instructions. When the computer instructions are executed by a processor, they complete the steps in the dynamic evaluation method for grounding short-circuit transfer potential of a power plant as described in Embodiment 1.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0041] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for dynamic evaluation of ground fault transfer potential in power plants, characterized in that, Includes the following steps: For the power plant to be evaluated, the apparent resistivity of the soil was measured using the Wenner quadrupole method, and the apparent resistivity-depth variation curve was constructed. For the fitted apparent resistivity-depth variation curve, an inversion algorithm is used, combined with analytical kernel function and Bessel function expansion, to inversely deduce the resistivity and thickness of each soil layer, and obtain the soil stratification parameters of multi-layered, non-uniform structure. The short-circuit current, grounding grid structure, and soil stratification parameters are obtained. A coupled simulation analysis combining the finite element method and the method of moments is used to obtain the grounding short-circuit transfer potential of the grounding grid of the power station to be evaluated. A method for obtaining the short-circuit current, grounding grid structure, and soil stratification parameters, and using a coupled simulation analysis combining the finite element method and the method of moments to determine the grounding short-circuit transfer potential of the power plant to be evaluated, includes the following steps: Obtain short-circuit current, grounding grid structure, and soil stratification parameters; Obtain the soil structure of the power plant to be evaluated and divide the area according to soil homogeneity; For areas where soil uniformity is higher than a set value, the method of moments is used for simulation analysis to obtain the grounding short-circuit transfer potential of the corresponding area of ​​the power plant to be evaluated. For areas where soil uniformity is lower than a set value, the finite element method is used for simulation analysis to obtain the grounding short-circuit transfer potential of the corresponding area of ​​the grounding grid of the power station to be evaluated. Starting from a point current source, the transfer potential distribution of each region is calculated sequentially from the near field to the far field. Based on the point potential distribution calculated in the previous region, an equivalent boundary source is generated at the boundary of the region. When calculating the next region, the solution is obtained by receiving the equivalent boundary source data and extending to the far field to complete the calculation of the global potential field. The finite element method discretizes the entire computational domain into a finite number of small elements and uses an interpolation function to approximate the potential distribution within each element. The computational domain includes soil, grounding grid, and air. The calculation process for finite element method simulation analysis is as follows: Use finite element software to create grounding grid and soil models; Based on the obtained current injection values ​​and soil stratification data, the Poisson equation is solved using the Galerkin method or the weighted residual method to obtain the point parameters of surface potential distribution, step voltage, and contact voltage. The calculation process for simulation analysis using the method of moments is as follows: Establish a grounding grid model, with discrete conductor surfaces represented as triangular or quadrilateral patches; Based on the obtained current injection values ​​and soil stratification data, the established electric field integral equation is solved to calculate the conductor current distribution and thus obtain the surface potential.

2. The method for dynamic evaluation of ground fault transfer potential in a power plant as described in claim 1, characterized in that: For the fitted apparent resistivity-depth variation curve, an inversion algorithm is used, combining analytical kernel function and Bessel function expansion, to deduce the resistivity and thickness of each soil layer, thus obtaining the stratification parameters of multi-layered, non-uniform soil structures. The method includes the following steps: Assuming the ground surface is an infinitely large horizontal plane and the underground consists of multiple layers of horizontally homogeneous soil, a layered soil physical model is constructed. Based on the constructed layered soil physical model, the Laplace equation is used to establish the governing equations for the potential V at each spatial location in the cylindrical coordinate system. Set the boundary conditions for the governing equation of potential V, including interlayer boundary continuity conditions, surface boundary conditions, and infinite boundary conditions. The method of separation of variables was adopted, and the governing equation of potential V was decomposed using the Bessel function expansion form to obtain the potential expression of each soil layer. The unknown coefficients in the potential expression were then solved based on the set boundary conditions. Based on the potential expression of a point current source at any point on the earth's surface related to soil stratification parameters, and the apparent resistivity measurement formula, the relationship between the apparent soil resistivity measurement value and the soil stratification parameters is obtained. Obtain the measured apparent resistivity data, solve the relationship between the measured apparent soil resistivity and the soil stratification parameters, and obtain the soil stratification parameters.

3. The method for dynamic evaluation of ground fault transfer potential in a power plant as described in claim 1, characterized in that: The relationship between apparent soil resistivity and the distance between measuring electrodes was measured using the equidistant Wenner four-electrode method.

4. The method for dynamic evaluation of ground fault transfer potential in a power plant as described in claim 1, characterized in that: The Poisson equation is: ； Where σ is the conductivity, Let J be the electric potential, and J be the current density.

5. A dynamic evaluation system for ground fault transfer potential in power plants, characterized in that, include: The module is configured to measure the apparent resistivity of the soil using the Wenner quadrupole method for the power plant to be evaluated, and to construct an apparent resistivity-depth curve. The inversion module is configured to use an inversion algorithm to deduce the resistivity and thickness of each soil layer by combining analytical kernel function and Bessel function expansion for the fitted apparent resistivity-depth variation curve, thus obtaining the soil stratification parameters of multi-layered, non-uniform structure. The coupled solution module is configured to obtain short-circuit current, grounding grid structure, and soil stratification parameters. It uses a coupled simulation analysis combining the finite element method and the method of moments to obtain the grounding short-circuit transfer potential of the grounding grid of the power station to be evaluated. A method for obtaining the short-circuit current, grounding grid structure, and soil stratification parameters, and using a coupled simulation analysis combining the finite element method and the method of moments to determine the grounding short-circuit transfer potential of the power plant to be evaluated, includes the following steps: Obtain short-circuit current, grounding grid structure, and soil stratification parameters; Obtain the soil structure of the power plant to be evaluated and divide the area according to soil homogeneity; For areas where soil uniformity is higher than a set value, the method of moments is used for simulation analysis to obtain the grounding short-circuit transfer potential of the corresponding area of ​​the power plant to be evaluated. For areas where soil uniformity is lower than a set value, the finite element method is used for simulation analysis to obtain the grounding short-circuit transfer potential of the corresponding area of ​​the grounding grid of the power station to be evaluated. Starting from a point current source, the transfer potential distribution of each region is calculated sequentially from the near field to the far field. Based on the point potential distribution calculated in the previous region, an equivalent boundary source is generated at the boundary of the region. When calculating the next region, the solution is obtained by receiving the equivalent boundary source data and extending to the far field to complete the calculation of the global potential field. The finite element method discretizes the entire computational domain into a finite number of small elements and uses an interpolation function to approximate the potential distribution within each element. The computational domain includes soil, grounding grid, and air. The calculation process for finite element method simulation analysis is as follows: Use finite element software to create grounding grid and soil models; Based on the obtained current injection values ​​and soil stratification data, the Poisson equation is solved using the Galerkin method or the weighted residual method to obtain the point parameters of surface potential distribution, step voltage, and contact voltage. The calculation process for simulation analysis using the method of moments is as follows: Establish a grounding grid model, with discrete conductor surfaces represented as triangular or quadrilateral patches; Based on the obtained current injection values ​​and soil stratification data, the established electric field integral equation is solved to calculate the conductor current distribution and thus obtain the surface potential.

6. An electronic device, characterized in that, It includes a memory and a processor, as well as computer instructions stored in the memory and running on the processor, which, when executed by the processor, complete the steps in the dynamic evaluation method for grounding short-circuit transfer potential of a power plant as described in any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, Used to store computer instructions, which, when executed by a processor, complete the steps in the dynamic evaluation method for grounding short-circuit transfer potential of a power plant as described in any one of claims 1-4.

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