Power transformation primary service calculation method and system

Abstract

The application belongs to the technical field of electric power engineering design, and is a power transformation primary service calculation method, comprising the following steps: S1, constructing a space physical model containing three-dimensional entities and material attributes, and performing adaptive grid division; S2, establishing a control logic, soil layering, and circuit and electromagnetic field coupling model; S3, performing time domain, frequency domain and sequential operation mixed simulation on the coupling model; S4, performing safety evaluation based on three-dimensional physical field, and performing multi-objective optimization design on the grounding system; and S5, performing four-dimensional visualization on the simulation and optimization results. A calculation system comprises a data fusion modeling unit, an integrated coupling solving unit, a mixed simulation scheduling unit, a safety evaluation optimization unit and a visualization decision support unit. The application overcomes the defects of excessive simplification of the traditional method model, neglect of soil layering and skin effect, and can accurately depict the spatial electromagnetic field distribution under complex geometric arrangement.

Description

Technical Field

[0001] This invention belongs to the field of power engineering design technology, specifically the calculation method and system for primary business operations of power substations. Background Technology

[0002] As high-voltage transmission technology rapidly develops towards multi-circuit and compact designs on single towers, the spatial structure between lines is becoming increasingly dense, significantly enhancing electromagnetic coupling effects. This results in a marked increase in the amplitude of induced voltage and current on lines undergoing maintenance or shutdown. This phenomenon not only increases the complexity of operation and maintenance work but also poses a more severe challenge to the safety of on-site personnel. Meanwhile, in substations—critical nodes in the power system—the current dissipation capacity of the grounding system and its potential distribution characteristics directly affect the level of ground potential rise under fault conditions, thus determining the specific values ​​of step voltage and contact voltage. These factors directly relate to the safe and stable operation of the power grid and the effective protection of personnel and equipment safety, and therefore have become core aspects that must be given high priority in power system design and operation.

[0003] Currently, the industry commonly uses manual or semi-automatic calculation methods based on simplified empirical formulas and coefficients. For example, patent document CN111222208A discloses a calculation method and system for primary operations in power substations. This type of prior art has the following significant drawbacks: 1. Oversimplification of the model: The distribution coefficient method of lumped parameters cannot accurately describe the true distribution of the spatial electromagnetic field under complex geometric layouts (such as multiple circuits and irregular grounding grids), and ignores key physical factors such as soil stratification and conductor skin effect; 2. Limited computational scope: It only performs steady-state calculations at power frequency and cannot simulate rapid changes in induced voltage and ground potential during dynamic transient processes such as switching operations, lightning strikes, and short-circuit faults; 3. Safety assessment relies on empirical coefficients: The calculation of contact potential and step potential heavily relies on empirical formulas and coefficients, which are based on idealized assumptions and have large errors under complex grounding grids or non-uniform soil conditions. 4. Disconnect between analysis and design: The coupling between calculation modules is weak, and each module operates relatively independently. There is a lack of a unified model from electromagnetic field to circuit parameters to safety indicators. At the same time, there is a lack of automatic optimization capabilities for grounding grid layout and equipment configuration. The design process relies on manual trial and error. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies and solve at least one technical problem mentioned in the background, the present invention aims to provide an economical and practical method and system for calculating primary operations in power substations. This method overcomes the shortcomings of traditional methods, such as oversimplification of models and neglect of soil stratification and skin effect. By constructing an integrated coupled model of "control logic-soil stratification-circuit-electromagnetic field," and employing adaptive mesh generation and full-wave Maxwell's equations, it can accurately characterize the spatial electromagnetic field distribution under complex geometric arrangements. Through hybrid simulation of time domain, frequency domain, and sequential operation, it can simulate dynamic processes under all operating conditions, including power frequency steady state, switching operation, and lightning strike faults. This results in more accurate and reliable calculations of induced voltage, ground potential rise, step voltage, and contact potential, providing a solid physical foundation for safety assessment.

[0005] The technical solution adopted by this invention to solve its technical problem is: the power substation primary business calculation method of this invention includes the following steps: S1. Construct a spatial physical model containing three-dimensional entities and material properties based on multi-source data, and perform adaptive mesh generation; S2. Establish a coupled model of control logic, soil stratification, circuit and electromagnetic field and solve it simultaneously to obtain accurate line electrical quantities and spatial field quantities. S3. Perform time-domain, frequency-domain, and sequential operation hybrid simulations on the coupled model to simulate the system response under different operating and maintenance conditions; S4. Conduct a safety assessment based on a three-dimensional physical field and perform multi-objective optimization design for the grounding system; S5. Visualize the simulation and optimization results in four dimensions to generate a risk heat map, safe operation zone delineation, and comprehensive analysis report.

[0006] Preferably, in step S1, the three-dimensional entity includes transmission lines, towers, grounding grids, buildings, and soil layering structures; the material properties include electrical conductivity, magnetic permeability, and dielectric constant.

[0007] Preferably, the specific implementation process of step S2 includes: S21. Define the control vector S to describe the opening and closing state of the grounding switch on the maintenance line, and define the system operation topology matrix. Describe the power grid operation mode; S22. Model the earth as a horizontally layered medium, with each layer i having independent electromagnetic property parameters, including conductivity. Dielectric constant magnetic permeability and layer thickness ; S23. Establish the frequency domain telegraph equations for a multi-conductor transmission line, including its distributed parameter impedance matrix. and admittance matrix It is a dynamic matrix, updated in real time by the electromagnetic field solution through coupling relationships: ; ; ; in, and This represents the phasor distribution of voltage and current along the length of the conductor; The internal impedance of the conductor; External induced impedance; For ground conductivity; Angular frequency; It is a dynamic capacitance matrix; S24. Establish the full-wave Maxwell equations within the computational domain Ω, which includes all conductors and layered soil: ; ; Where E and H are the electric and magnetic field strengths, respectively; j: represents the imaginary unit; and For external magnetic flux density source and current density source; S25. Strongly couple the control logic, circuit equations, and electromagnetic field equations to form a unified algebraic system for simultaneous solution: ; in, The matrix of the finite element system in the field; For the circuit system matrix; and This is the coupling matrix; and These are the unknown vectors for the electromagnetic field and the circuit, respectively; and The source vector; This is the excitation voltage source vector.

[0008] Preferably, in step S24, an impedance boundary condition is applied to the conductor surface: ;in, is the unit normal vector of the conductor surface; The surface impedance of the conductor.

[0009] Preferably, the specific implementation process of step S3 includes: S31. Perform frequency domain sweep in the target frequency band and generate a reduced-order model based on the calculation results; S32. Use a reduced-order model or the finite-difference time-domain method to perform time-domain simulations of transient processes such as switching operations and lightning strikes. S33. Based on the preset maintenance operation sequence, drive the coupled model to perform sequential simulation to simulate the risk evolution throughout the entire process.

[0010] Preferably, in step S31, the method for generating the reduced-order model is as follows: By using vector matching or Krylov subspace projection, the high-dimensional system matrix K is projected onto a low-dimensional subspace, generating a high-precision rational function reduced-order model. ;in, ; It is the extreme point; Residue; , is a constant term; i: summation subscript, with a value range of 1, 2, ..., q; where q is the order of the rational function of the reduced-order model, which is a positive integer.

[0011] Preferably, the specific implementation process of step S4 includes: S41. Directly extracting the surface potential distribution from the field solution. The true maximum step potential is calculated through a global search. and maximum contact potential No experience coefficient is required; S42. Establish a system with the grounding grid design parameter p as the variable and the grounding resistance as the variable. Maximum contact potential Maximum step potential and cost A multi-objective optimization problem with a target. S43. Using an optimization process based on the Kriging proxy model and the expected improvement point addition criterion, the Pareto optimal solution set is automatically searched to obtain an optimized grounding system design scheme.

[0012] Preferably, in step S41, the maximum step potential The following was obtained by searching and calculating all possible step paths: ;in, Let be the coordinate vector of any point on the Earth's surface; This is the unit direction vector on the Earth's surface.

[0013] Preferably, in step S41, the maximum contact potential The following was obtained through a search and calculation of all possible contact points: ;in, For device potential; The direction in which a person stands.

[0014] The power substation primary service calculation system of the present invention is applied to the above-mentioned power substation primary service calculation method and includes a data fusion modeling unit, an integrated coupled solution unit, a hybrid simulation scheduling unit, a security assessment and optimization unit, and a visualization decision support unit.

[0015] The beneficial effects of this invention are as follows: 1. The power substation primary business calculation method and system described in this invention, by constructing an integrated coupled model of "control logic-soil stratification-circuit-electromagnetic field", and by adopting adaptive mesh generation and full-wave Maxwell's equations solution, overcomes the defects of traditional methods such as oversimplification of models and neglect of soil stratification and skin effect. It can accurately characterize the spatial electromagnetic field distribution under complex geometric layout. Through time domain, frequency domain and sequential operation hybrid simulation, it realizes the simulation of dynamic processes under all working conditions such as power frequency steady state, switching operation, lightning strike fault, etc., making the calculation results of induced voltage, ground potential rise, step and contact potential more accurate and reliable, and providing a solid physical basis for safety assessment.

[0016] 2. The power substation primary business calculation method and system described in this invention directly extracts safety indicators based on a three-dimensional physical field and establishes an optimization model with grounding resistance, safety potential, and cost as objectives. Combined with the Kriging proxy model and the expected improvement criterion, it can automatically search the Pareto optimal solution set and output an economical and safe grounding system design scheme. This not only greatly improves design efficiency but also reduces safety risks and cost waste caused by conservative or insufficient design.

[0017] 3. The power substation primary business calculation method and system described in this invention integrates multi-source data to construct a three-dimensional high-fidelity model and uses four-dimensional visualization technology to dynamically render the simulation and optimization results, generating risk heat maps, safe operation zones, and interactive analysis reports. This achieves a deep integration of the calculation process and result expression, providing an intuitive and efficient digital platform for power grid planning, maintenance operations, and safety training, and strongly supporting the development direction of intelligent operation and maintenance and refined management of power systems. Attached Figure Description

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0020] Figure 2 This is a schematic diagram of the computing system composition of the present invention. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0022] Example 1: like Figure 1 As shown, the power substation primary service calculation method of the present invention includes the following steps: S1. Construction of a high-fidelity space physics model based on multi-source data; The goal of this step is to establish a computational geometry and property model that strictly corresponds to the real physical world, providing accurate input for numerical calculations, as follows: S11. Mapping of 3D Solid Model and Material Properties: Geometric modeling: Based on design drawings or point cloud data, a parametric 3D model of the substation is constructed, including: transmission lines, towers, grounding grid, and buildings; the model is represented by non-uniform rational B-spline (NURBS) surfaces to ensure geometric accuracy; Attribute association: Define electromagnetic material properties for each geometric entity; For metallic conductors (wires, grounding bodies), their electrical conductivity is defined; for soil and air, their complex permittivity is defined; for the layered soil model, the earth is regarded as a horizontally layered medium, each layer having its thickness, electrical conductivity, magnetic permeability and permittivity. This design is a fundamental improvement on the homogeneous soil assumption in the prior art.

[0023] S12, Adaptive computational grid generation ensures efficient allocation of computing resources: The Delaunay triangulation algorithm is used to generate a three-dimensional tetrahedral computational mesh; A grid-adaptive strategy based on curvature and field gradient estimation is introduced to automatically refine the grid size at the conductor surface, near the grounding electrode, and at the soil layer interface to meet numerical accuracy requirements.

[0024] S2. Establishment and discretization of an integrated coupled mathematical model of “control domain-soil stratification domain-circuit domain-electromagnetic field domain”; The goal of this step is to establish a unified mathematical model that describes control logic, soil stratification, circuits, and electromagnetic fields, as detailed below: S21. Control Domain Modeling (Behavioral Logic): Define the switch state vector ,in, 1 indicates a closed circuit (grounded), and 0 indicates an open circuit; for example, This indicates the status of the grounding switch at the beginning of the line under maintenance. Define the system operation topology matrix It is a node-branch correlation matrix whose elements change dynamically depending on which lines are in operation and which are out of operation. This matrix directly affects the construction of subsequent circuit equations.

[0025] S22, Soil Stratification Domain Modeling (Physical Environment): This is a fundamental improvement over traditional homogeneous soil models, modeling the earth as a horizontally layered medium, with each layer i having independent electromagnetic property parameters: conductivity. Dielectric constant magnetic permeability and layer thickness .

[0026] S23, Circuit Domain Modeling (Multi-Conductor Systems): Treating N parallel wires as a multi-conductor transmission line system, its telegraph equations in the frequency domain are completely described by a distributed parameter matrix per unit length: ; In traditional methods, the impedance matrix and admittance matrix These are fixed values; in this method, they are dynamic matrices decoupled from the field domain. ; ; in, and This represents the phasor distribution of voltage and current along the length of the conductor; The internal impedance of the conductor includes the skin effect. The external induced impedance needs to be obtained by solving the relationship between the vector magnetic potential A of the conductor cross section and the current in the field. Its conductivity to ground is usually negligible; Angular frequency; The dynamic capacitance matrix is ​​obtained by coupling with the field domain. The potential coefficient matrix is ​​calculated by solving the electrostatic field distribution of the cross section under unit voltage, and then the potential coefficient matrix is ​​inverted.

[0027] S24. Electromagnetic Field Modeling (Full-Wave Maxwell's Equations): Within the computational domain Ω, the governing equations are the full-wave Maxwell equations: ; ; Where E and H are the electric field and magnetic field strengths, respectively; and For external magnetic flux density source and current density source; In this invention and in most electromagnetic calculations for power systems, an external magnetic current source is typically absent. Therefore, in this embodiment, an external magnetic current source can be set. Then the Maxwell equation above can be simplified to: ; ; Boundary conditions: On the surface of the conductor Above, the impedance boundary condition is satisfied: ,in, is the unit normal vector of the conductor surface; The surface impedance of the conductor is used to accurately simulate the skin effect; At the outer boundary of the computational domain Above, a perfectly matched layer (PML) is applied to absorb outgoing waves to simulate an open-domain problem; At the soil stratification interface Above, the boundary condition of continuous tangential component of electromagnetic field is satisfied.

[0028] S25. Coupling Mechanisms and Unified Solution Systems: The contribution of the electromagnetic field domain to the circuit domain: The electromagnetic field solution provides the necessary parameters for updating the circuit. and ; Excitation of the electromagnetic field by the circuit domain: The conductor current calculated by the circuit is mapped to the excitation source in the field. ; Constraints of the control domain on the circuit domain: switching state S and operating topology Define the boundary conditions of the circuit equations directly; Definition of electromagnetic field domain in soil stratification domain: Soil stratification structure through electrical conductivity Dielectric constant magnetic permeability It directly affects the distribution of the electromagnetic field throughout the entire domain; Finally, the field equations are discretized using the finite element method (FEM), the circuit equations are processed using the frequency domain transmission line matrix method or the finite difference method, and the entire coupled algebraic system is solved using Newton-Raphson iteration or block Gaussian elimination. ; in, The matrix of the finite element system in the field; For the circuit system matrix; and This is the coupling matrix; and These are the unknown vectors for the electromagnetic field and the circuit, respectively; and The source vector; This is the excitation voltage source vector.

[0029] S3, Time-Frequency-Sequential Hybrid Simulation Strategy: The goal of this step is to comprehensively assess steady-state, transient, and operational risks using hybrid simulation, as detailed below: S31. Frequency domain sweep and reduced-order model (ROM) generation: In the frequency bands of interest Within a range from a power frequency of 50Hz to a lightning wave frequency of 1MHz, the above coupled system is solved with a certain step size to obtain the system's response in the frequency domain. (e.g., transfer impedance, induced voltage ratio); By using vector matching or Krylov subspace projection, the high-dimensional system matrix K is projected onto a low-dimensional subspace, generating a high-precision rational function reduced-order model: ; in, ; The extreme point; Residue; , This is a constant term; the generation of ROM improves the efficiency of subsequent time-domain and parameter scan simulations by several orders of magnitude.

[0030] S32, Time-Domain Transient Simulation: For fast-rising transients such as switching operations and lightning strikes, the time-domain response can be efficiently calculated using the frequency domain response represented by ROM or rational functions through numerical inverse Laplace transform (such as Fourier transform or recursive convolution). ; For scenarios involving nonlinear components (such as surge arresters), the time-domain finite element method (FDTD) is used to directly solve the time-domain Maxwell equations, and co-simulation is performed with a circuit simulator (such as SPICE). The two exchange data at each time step through node voltage and branch current to achieve strict synchronization.

[0031] S33. Sequential Operation Simulation: Define a sequence of operation events arranged in chronological order: ; The simulation engine switches the control vector S and the topology matrix at corresponding moments based on the event sequence. This can trigger a new time-domain or frequency-domain simulation; this can simulate the dynamic evolution of induced voltage and ground potential as the operation progresses throughout the maintenance process.

[0032] S4. Safety assessment and adaptive optimization based on three-dimensional physical fields; The goal of this step is to directly extract and optimize security indicators from the physical field, as follows: S41. High-precision safety parameter extraction: Surface potential distribution: Direct extraction of surface nodal potentials from the field solution ; Step potential: Search for the maximum potential difference across all possible step paths (1m long, arbitrary direction): ; in, Let be the coordinate vector of any point on the Earth's surface; This is the unit direction vector on the Earth's surface, representing the step direction; Contact potential: at all possible contact points on the equipment casing or frame. Calculation at point: ; in, The device potential is obtained from field solutions or circuit solutions; The direction in which the human body stands is considered; this method eliminates the errors caused by empirical coefficients in existing technologies. Human body electrical pathway assessment: establishing a path that includes human body impedance and shoe and sock resistance The equivalent circuit model is coupled with the surface potential distribution to directly calculate the current that may flow through the human body. And compare it with safety thresholds (such as ventricular fibrillation threshold).

[0033] S42. Multi-objective parameterization optimization of grounding systems: Design variable parameterization: Define a set of parameters to control the geometry of the grounding grid. Such as grid spacing, length and location of vertical grounding electrodes, conductor radius, etc.; Establish a multi-objective optimization problem: in, The objective function vector; Grounding resistance; This represents the maximum contact potential. This represents the maximum step potential. For cost.

[0034] S43. Efficient optimization based on the proxy model: Experimental design: Within the design space, N sample points are generated using Latin hypercube sampling. ; High-fidelity simulation: for each sample point Perform the aforementioned coupled calculations to obtain the objective function value. ; Agent model construction: for each target Construct Kriging proxy models respectively The Kriging model not only provides predicted values, but also the predicted variance. ; Point addition criteria and iterative optimization: Using a multi-criteria point addition strategy such as expected improvement (EI), new points with high uncertainty are found to improve the objective function value and are used for high-fidelity simulation to update the surrogate model; this process is repeated until convergence, and Pareto digital twin-driven panoramic visualization and decision support are obtained.

[0035] S5, digital twin-driven panoramic visualization and decision support; The goal of this step is to integrate the calculation results into an interactive 3D visualization platform to form a decision-making dashboard, as detailed below: Four-dimensional physics rendering: Using scientific visualization techniques, such as volume rendering, isosurfaces, and streamlines, to render the spatial distribution of electromagnetic field strength, surface potential, current density, etc., and their animation over time (or frequency) in real time. Risk heat map and safety zoning: based on , , The calculation results are overlaid on the surface model with a color-coded risk heat map, which intuitively displays the zoning of hazardous areas and safe work areas, as well as a comprehensive analysis report. Virtual work simulation: In the digital twin, a virtual worker moves according to a predetermined step. The system calculates and displays the safety parameters of the worker's location in real time, such as foot-to-foot voltage and touch voltage, and provides early warning of impending risks of exceeding the standard. Optimization Scheme Comparison and Report Generation: The system displays the grounding grid design, safety indicators, and costs of different optimization schemes (different solutions on the Pareto front) side by side, supports interactive user trade-offs, and automatically generates a comprehensive analysis report containing detailed simulation conditions, results, risk diagrams, and optimization suggestions.

[0036] Example 2: like Figure 2 As shown, the power substation primary business calculation system of the present invention is applied to the above-mentioned power substation primary business calculation method, and includes a data fusion modeling unit, an integrated coupled solution unit, a hybrid simulation scheduling unit, a security assessment and optimization unit, and a visualization decision support unit. The data fusion modeling unit is used to import and integrate geographic information, design drawings, equipment parameters and soil data, construct a three-dimensional parametric model and generate a computational grid; The integrated coupled solution unit is used to embed a coupled mathematical model containing control logic, soil stratification, circuit and electromagnetic field, and calls the finite element method and circuit solver to perform simultaneous calculations; The hybrid simulation scheduling unit is used to manage the execution flow of frequency domain sweep, time domain transient simulation, and sequential operation simulation. The security assessment and optimization unit is used to extract security indicators from the three-dimensional physical field, drive the agent model optimization process, and output an optimized design scheme. The visualization decision support unit is used to render a four-dimensional physical field, draw a risk heat map, simulate virtual operations, and generate reports.

[0037] The terms "front," "back," "left," "right," "top," and "bottom" all refer to the figures in the accompanying drawings. Figure 1 Based on the perspective of the observer, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0038] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for calculating primary business operations in power substations, characterized in that: Includes the following steps: S1. Construct a spatial physical model containing three-dimensional entities and material properties based on multi-source data, and perform adaptive mesh generation; S2. Establish a coupled model of control logic, soil stratification, circuit and electromagnetic field and solve it simultaneously to obtain accurate line electrical quantities and spatial field quantities. S3. Perform time-domain, frequency-domain, and sequential operation hybrid simulations on the coupled model to simulate the system response under different operating and maintenance conditions; S4. Conduct a safety assessment based on a three-dimensional physical field and perform multi-objective optimization design for the grounding system; S5. Visualize the simulation and optimization results in four dimensions to generate a risk heat map, safe operation zone delineation, and comprehensive analysis report.

2. The method for calculating primary business operations of power substations according to claim 1, characterized in that: In step S1, the three-dimensional entity includes transmission lines, towers, grounding grids, buildings, and soil layering structures; the material properties include electrical conductivity, magnetic permeability, and dielectric constant.

3. The method for calculating primary business operations of power substations according to claim 1, characterized in that: The specific implementation process of step S2 includes: S21. Define the control vector S to describe the opening and closing state of the grounding switch on the maintenance line, and define the system operation topology matrix. Describe the power grid operation mode; S22. Model the earth as a horizontally layered medium, with each layer i having independent electromagnetic property parameters, including conductivity. Dielectric constant magnetic permeability and layer thickness ; S23. Establish the frequency domain telegraph equations for a multi-conductor transmission line, including its distributed parameter impedance matrix. and admittance matrix It is a dynamic matrix, updated in real time by the electromagnetic field solution through coupling relationships: ； ； ； in, and This represents the phasor distribution of voltage and current along the length of the conductor; The internal impedance of the conductor; External induced impedance; For ground conductivity; Angular frequency; It is a dynamic capacitance matrix; S24. Establish the full-wave Maxwell equations within the computational domain Ω, which includes all conductors and layered soil: ； ； Where E and H are the electric and magnetic field strengths, respectively; j: represents the imaginary unit; and For external magnetic flux density source and current density source; S25. Strongly couple the control logic, circuit equations, and electromagnetic field equations to form a unified algebraic system for simultaneous solution: ； in, The matrix of the finite element system in the field; For the circuit system matrix; and This is the coupling matrix; and These are the unknown vectors for the electromagnetic field and the circuit, respectively; and The source vector; This is the excitation voltage source vector.

4. The method for calculating primary business operations of power substations according to claim 3, characterized in that: In step S24, impedance boundary conditions are applied to the conductor surface: ； in, is the unit normal vector of the conductor surface; The surface impedance of the conductor.

5. The method for calculating primary business operations in power substations according to claim 1, characterized in that: The specific implementation process of step S3 includes: S31. Perform frequency domain sweep in the target frequency band and generate a reduced-order model based on the calculation results; S32. Use a reduced-order model or the finite-difference time-domain method to perform time-domain simulation of the transient process of switching operation and lightning strike fault; S33. Based on the preset maintenance operation sequence, drive the coupled model to perform sequential simulation to simulate the risk evolution throughout the entire process.

6. The method for calculating primary business operations of power substations according to claim 5, characterized in that: In step S31, the method for generating the reduced-order model is as follows: By using vector matching or Krylov subspace projection, the high-dimensional system matrix K is projected onto a low-dimensional subspace, generating a high-precision rational function reduced-order model. ； in, ; The extreme point; Residue; , is a constant term; i: summation subscript, with a value range of 1, 2, ..., q; where q is the order of the rational function of the reduced-order model, which is a positive integer.

7. The method for calculating primary business operations of power substations according to claim 1, characterized in that: The specific implementation process of step S4 includes: S41. Directly extracting the surface potential distribution from the field solution. The true maximum step potential is calculated through a global search. and maximum contact potential ; S42. Establish a system with the grounding grid design parameter p as the variable and the grounding resistance as the variable. Maximum contact potential Maximum step potential and cost A multi-objective optimization problem with a target. S43. Using an optimization process based on the Kriging proxy model and the expected improvement point addition criterion, the Pareto optimal solution set is automatically searched to obtain an optimized grounding system design scheme.

8. The method for calculating primary business operations in power substations according to claim 7, characterized in that: In step S41, the maximum step potential The following was obtained by searching and calculating all possible step paths: ； in, Let be the coordinate vector of any point on the Earth's surface; This is the unit direction vector on the Earth's surface.

9. The method for calculating primary business operations of power substations according to claim 7, characterized in that: In step S41, the maximum contact potential The following was obtained through a search and calculation of all possible contact points: ； in, For device potential; The direction in which a person stands.

10. A power substation primary service calculation system, wherein the system is applied to the power substation primary service calculation method according to any one of claims 1-9, characterized in that: It includes a data fusion modeling unit, an integrated coupled solution unit, a hybrid simulation scheduling unit, a security assessment and optimization unit, and a visualization decision support unit; The data fusion modeling unit is used to import and integrate geographic information, design drawings, equipment parameters and soil data, construct a three-dimensional parametric model and generate a computational grid; The integrated coupled solution unit is used to embed a coupled mathematical model containing control logic, soil stratification, circuit and electromagnetic field, and calls the finite element method and circuit solver to perform simultaneous calculations; The hybrid simulation scheduling unit is used to manage the execution flow of frequency domain sweep, time domain transient simulation, and sequential operation simulation. The security assessment and optimization unit is used to extract security indicators from the three-dimensional physical field, drive the agent model optimization process, and output an optimized design scheme. The visualization decision support unit is used to render a four-dimensional physical field, draw a risk heat map, simulate virtual operations, and generate reports.

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