Extreme geomagnetic induction current evaluation method and device based on regional power grid, terminal equipment and storage medium

Abstract

The invention discloses an extreme geomagnetic induction current evaluation method and device based on a regional power grid, terminal equipment and a storage medium, and belongs to the field of power systems. The method comprises the following steps: acquiring geomagnetic disturbance data of each geomagnetic station of a regional power grid to be evaluated, geomagnetic conductivity data of a geomagnetic induction current region, power grid topological structure data and power grid equipment configuration parameters; constructing a ground conductivity model according to the ground conductivity data; according to the geologic structure corresponding to the regional power grid to be evaluated, the geomagnetic disturbance data and the earth conductivity model, an induction earth electric field under geomagnetic disturbance is obtained through calculation; constructing a regional power grid node simulation model according to the power grid topological structure data and the power grid equipment configuration parameters; and according to the regional power grid node simulation model and the induced geoelectric field, calculating to obtain geomagnetic induced current distribution of each node of the to-be-evaluated regional power grid. According to the invention, the problem of lack of geomagnetic induction current evaluation in the prior art can be solved.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a method, apparatus, terminal equipment, and storage medium for assessing extreme geomagnetic induced current based on a regional power grid. Background Technology

[0002] Solar activity, such as coronal mass ejections or high-speed solar winds, ejects a large number of charged particles toward Earth. These particles interact with Earth's magnetic field, causing rapid changes in the strength and direction of the magnetic field and resulting in strong geomagnetic disturbances. Due to the Earth's electrical conductivity, the changing geomagnetic field induces an electric field on the Earth's surface. This induced electric field generates low-frequency geomagnetic induced currents in closed loops formed by transmission lines, transformer grounding neutral points, and the Earth's conductors, adversely affecting the power grid. Because of the low frequency of these geomagnetic induced currents, they can be considered quasi-DC. When these currents flow through transformers, they generate DC bias magnetism in the transformer core, leading to an increase in magnetic flux. This forces the core to operate in the saturation region of its magnetization curve, distorting the excitation current. This results in increased reactive power losses, increased harmonics, and vibration noise. Simultaneously, the geomagnetic induced current also adversely affects secondary equipment, and in severe cases, threatens the normal operation of the power system.

[0003] Due to latitudinal differences in the Earth's magnetic field, high-latitude regions experience strong geomagnetic disturbances and are severely affected by geomagnetic induced currents. Although my country is mainly located in the mid-to-low latitudes, its large-scale and complex power grid is susceptible to the effects of geomagnetic storms. Furthermore, the lack of assessment of extreme geomagnetic induced currents in regional power grids makes it difficult to guarantee the safe and stable operation of large-scale high-voltage power grids under geomagnetic disturbances. Summary of the Invention

[0004] This invention provides a method, apparatus, terminal equipment, and storage medium for assessing extreme geomagnetic induced currents based on regional power grids, which can effectively solve the problem that existing technologies lack the ability to assess extreme geomagnetic induced currents in regional power grids.

[0005] One embodiment of the present invention provides a method for assessing extreme geomagnetic induced current based on a regional power grid, comprising:

[0006] Obtain geomagnetic disturbance data, geodetic conductivity data of geomagnetic induced current areas, power grid topology data, and power grid equipment configuration parameters from various geomagnetic stations in the power grid to be evaluated area.

[0007] Based on the aforementioned earth conductivity data, an earth conductivity model is constructed.

[0008] Based on the geological structure of the power grid in the area to be evaluated, the geomagnetic disturbance data, and the earth conductivity model, the induced geoelectric field under geomagnetic disturbance is calculated.

[0009] Based on the power grid topology data and the power grid equipment configuration parameters, a regional power grid node simulation model is constructed.

[0010] Based on the regional power grid node simulation model and the induced geoelectric field, the geomagnetic induced current distribution of each node in the regional power grid to be evaluated under a geomagnetic storm event is calculated.

[0011] Furthermore, the geomagnetic disturbance data includes a magnetic field component; the earth conductivity data includes: a one-dimensional earth conductivity parameter for characterizing the vertical stratification of conductivity, and a three-dimensional earth conductivity parameter for characterizing the non-uniform variation of conductivity in three dimensions.

[0012] Based on the aforementioned earth conductivity data, an earth conductivity model is constructed, including:

[0013] Based on the one-dimensional earth conductivity parameters, a one-dimensional conductivity model is constructed to characterize the vertical stratification structure.

[0014] Based on the three-dimensional earth conductivity parameters, a three-dimensional conductivity model is constructed to characterize three-dimensional non-uniform structures.

[0015] One-dimensional or three-dimensional conductivity models are used as models of earth conductivity.

[0016] Furthermore, the geomagnetic disturbance data includes magnetic field components;

[0017] Based on the geological structure of the power grid area to be evaluated, the geomagnetic disturbance data, and the earth conductivity model, the induced geoelectric field under geomagnetic disturbance is calculated, including:

[0018] Wavelet analysis was performed on the magnetic field components in the geomagnetic disturbance data to obtain the first north-south component and the first east-west component used to characterize the magnetic field of the geomagnetic disturbance.

[0019] Fourier transforms are performed on the first north-south component and the first east-west component to obtain the second north-south component and the second east-west component, which are used to characterize the geomagnetic disturbance data in the frequency domain.

[0020] Based on the geological structure of the power grid in the area to be evaluated, determine the corresponding geoelectric conductivity model;

[0021] In the case of a horizontally layered geological structure, the depth and conductivity of each geological layer are determined based on a one-dimensional conductivity model.

[0022] The surface wave impedance is recursively calculated based on the preset vacuum permeability, preset angular frequency, depth of each geological layer, and conductivity.

[0023] The induced geoelectric field under geomagnetic disturbance is calculated based on the surface wave impedance, the preset angular frequency, and the preset magnetic field strength.

[0024] In the case of a non-horizontal layered geological structure, the conductivity distribution matrix of the grid cells and the geological structure boundary coordinates are extracted from the three-dimensional conductivity model.

[0025] Using the second north-south component and the second east-west component as boundary conditions, and based on the conductivity distribution matrix and the geological structure boundary coordinates, the finite element method is used to obtain the frequency domain induced geoelectric field spectrum data.

[0026] The induced geoelectric field under geomagnetic disturbance is obtained by performing discrete inverse Fourier transform on the frequency domain induced geoelectric field spectrum data.

[0027] Furthermore, the power grid equipment configuration parameters include voltage level, transformer winding connection method, and transformer combination method;

[0028] Based on the power grid topology data and the power grid equipment configuration parameters, a regional power grid node simulation model is constructed, including:

[0029] The power grid in the area to be evaluated is divided into different voltage levels according to the voltage level; the busbars and transformers in each voltage level are regarded as nodes.

[0030] Based on the power grid topology data, the relationships between nodes and lines in different voltage levels are established, and a topology correlation matrix is ​​obtained.

[0031] Construct the equivalent circuit of the transformer based on the transformer winding connection method and the transformer combination method;

[0032] Based on the topological correlation matrix, the equivalent circuit of the transformer is embedded in the initial node admittance matrix to obtain the simulation model of the regional power grid nodes; where the initial node admittance matrix represents the line admittance between different nodes.

[0033] Furthermore, based on the regional power grid node simulation model and the induced geoelectric field, the geomagnetic induced current distribution of each node in the power grid to be evaluated under a geomagnetic storm event is calculated, including:

[0034] The time-domain signal of the electric field is obtained by performing an inverse discrete Fourier transform operation on the induced ground electric field.

[0035] The electric field time-domain signal is mapped to both ends of the line in the simulation model of the regional power grid nodes, and the equivalent electromotive force between the nodes is calculated.

[0036] The total current source flowing into each node is calculated based on the equivalent electromotive force between nodes and the line admittance in the simulation model of the regional power grid nodes.

[0037] The voltage of each node is calculated based on the total current source flowing into each node and the node admittance matrix corresponding to the simulation model of the regional power grid nodes.

[0038] The geomagnetic induced current between each node is calculated based on the voltage of each node, the total current source flowing into each node, and the line admittance.

[0039] Based on the geomagnetic induced current between nodes, the distribution of geomagnetic induced current at each node of the power grid in the area to be evaluated under a geomagnetic storm event is obtained.

[0040] Furthermore, it also includes: conducting a system sensitivity analysis of the power grid in the area to be evaluated for a specific geomagnetic storm time based on the distribution of geomagnetic induced current at each node of the power grid in the area to be evaluated;

[0041] Based on the number of adjacent nodes of each node in the power grid topology data, the geomagnetic induced current of each node, and the preset node weight, the sensitivity of each node to the geomagnetic induced current is calculated.

[0042] Based on the sensitivity of each node to geomagnetic induced current and the preset sensitivity threshold, the risk levels of each node in the power grid of the area to be evaluated are classified.

[0043] Furthermore, it also includes: generating a node geomagnetic induced current heat map to characterize the distribution of geomagnetic induced current at each node of the regional power grid based on the geomagnetic induced current between each node;

[0044] The geographic coordinates corresponding to the geomagnetic induced current heat map of the node are matched with the electrical node coordinates corresponding to the regional power grid node simulation model to determine the mapping relationship between geographic and electrical coordinates.

[0045] Based on the mapping relationship between geographic and electrical coordinates, the geomagnetic induced current heat map of the nodes and the simulation model of the regional power grid nodes are superimposed, and each node is marked according to its risk level to obtain a visualized image of the regional power grid's response to geomagnetic storm events.

[0046] As an improvement to the above solution, another embodiment of the present invention provides an extreme geomagnetic induced current assessment device based on a regional power grid, comprising:

[0047] The power grid data acquisition module is used to acquire geomagnetic disturbance data, geodetic conductivity data of the geomagnetic induced current area, power grid topology data, and power grid equipment configuration parameters of the power grid in the area to be evaluated.

[0048] The conductivity model construction module is used to construct a ground conductivity model based on the ground conductivity data.

[0049] The induced geoelectric field calculation module is used to calculate the induced geoelectric field under geomagnetic disturbance based on the geological structure corresponding to the power grid in the area to be evaluated, the geomagnetic disturbance data, and the earth conductivity model.

[0050] The node simulation model construction module is used to construct a regional power grid node simulation model based on the power grid topology data and the power grid equipment configuration parameters.

[0051] The geomagnetic induced current assessment module is used to calculate the geomagnetic induced current distribution of each node of the power grid in the area to be assessed under a geomagnetic storm event, based on the simulation model of the regional power grid nodes and the induced geoelectric field.

[0052] Another embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements an extreme geomagnetic induced current assessment method based on a regional power grid as described in the above embodiments.

[0053] Another embodiment of the present invention provides a computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to perform the extreme geomagnetic induced current assessment method based on a regional power grid as described in the above embodiment.

[0054] By implementing this invention, at least the following beneficial effects are achieved:

[0055] This invention provides a method, device, terminal equipment, and storage medium for assessing extreme geomagnetic induced currents based on regional power grids. The method enables multi-dimensional data assessment using geomagnetic disturbance data, earth conductivity data, power grid topology data, and power grid equipment configuration parameters. Simultaneously, the earth conductivity data is adapted to different geological structures, resolving calculation errors in the induced geoelectric field caused by geological differences, and providing a data foundation for scenarios where geological conditions and power grid structures interact in large-scale power grids. An earth conductivity model is constructed based on the earth conductivity data, and the induced geoelectric field is calculated in conjunction with the geological structure of the power grid to be assessed. Simultaneously, a regional power grid node simulation model is constructed based on the power grid topology and equipment configuration parameters, fully considering the complexity of geological structures and the diversity of power grid topologies. This overcomes the distortion of actual conditions caused by model simplification in traditional assessments, enabling a more realistic simulation of the physical processes of the power grid under geomagnetic disturbances. Through the collaborative calculation of the regional power grid node simulation model and the induced geoelectric field, the distribution of geomagnetic induced currents at each node of the regional power grid under geomagnetic storm events can be accurately obtained. This multi-model coupled calculation method effectively overcomes the shortcomings of traditional assessment methods in adapting to complex power grids, enabling assessment results to penetrate all nodes of the power grid and cover the entire region, achieving a refined assessment of the impact of extreme geomagnetic induced currents, thereby ensuring the safe and stable operation of large-scale high-voltage power grids under geomagnetic disturbances. Attached Figure Description

[0056] Figure 1 This is a flowchart illustrating an extreme geomagnetic induced current assessment method based on a regional power grid, provided by an embodiment of the present invention.

[0057] Figure 2 This is another flowchart of the geomagnetic induced current evaluation method provided in one embodiment of the present invention;

[0058] Figure 3 This is a schematic diagram of a one-dimensional conductivity model provided in an embodiment of the present invention;

[0059] Figure 4 This is a schematic diagram of a three-dimensional conductivity model provided in an embodiment of the present invention;

[0060] Figure 5 This is a schematic diagram of a circuit for constructing a node admittance matrix according to an embodiment of the present invention;

[0061] Figure 6 This is a schematic diagram of the structure of an extreme geomagnetic induced current assessment device based on a regional power grid, provided in an embodiment of the present invention. Detailed Implementation

[0062] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] See Figure 1 To address the lack of assessment of extreme geomagnetic induced current in existing technologies, an embodiment of the present invention provides a flowchart illustrating a method for assessing extreme geomagnetic induced current based on a regional power grid, comprising:

[0064] S1. Obtain geomagnetic disturbance data, geomagnetic conductivity data of the geomagnetic induced current area, power grid topology data, and power grid equipment configuration parameters from various geomagnetic stations in the power grid to be evaluated area.

[0065] Specifically, geomagnetic disturbance data represents the time-varying intensity and direction of the Earth's magnetic field monitored by geomagnetic observatories. It is used to simulate the intensity and frequency characteristics of geomagnetic storms, including magnetic field components (in nT) and the date and time (in seconds) of the geomagnetic storm. Geomagnetic observatories are monitoring stations deployed on the Earth's surface that collect geomagnetic disturbance data using equipment such as fluxgate magnetometers. Power grid topology data describes parameters describing the connection relationships between power grid nodes (substations, buses) and branches (transmission lines, transformers), including node coordinates, line lengths, and models. Power grid equipment configuration parameters reflect the electrical characteristics of the equipment, such as voltage levels, transformer winding connection methods (Yyn0, Yd11, etc.), and combination methods (parallel, series).

[0066] In a preferred embodiment of the present invention, such as Figure 2 As shown, geomagnetic disturbance data, earth conductivity data, power grid topology data, and power grid equipment configuration parameters were collected to provide a foundation for subsequent modeling. By integrating multi-source data, the study covers geomagnetic storm excitation sources, earth conduction characteristics, and power grid response characteristics. This addresses the problems of single data sets and simplistic models in traditional methods, providing theoretical support for large-scale power grids to cope with geomagnetic storms and enhancing the power grid's security and defense capabilities.

[0067] S2. Construct a geoelectric conductivity model based on the aforementioned geoelectric conductivity data;

[0068] Preferably, the geomagnetic disturbance data includes a magnetic field component; the earth conductivity data includes: a one-dimensional earth conductivity parameter for characterizing the vertical stratification of conductivity, and a three-dimensional earth conductivity parameter for characterizing the non-uniform variation of conductivity in three dimensions.

[0069] Based on the aforementioned earth conductivity data, an earth conductivity model is constructed, including:

[0070] Based on the one-dimensional earth conductivity parameters, a one-dimensional conductivity model is constructed to characterize the vertical stratification structure.

[0071] Based on the three-dimensional earth conductivity parameters, a three-dimensional conductivity model is constructed to characterize three-dimensional non-uniform structures.

[0072] One-dimensional or three-dimensional conductivity models are used as models of earth conductivity.

[0073] Specifically, geodetic conductivity data is a set of parameters used to describe the electrical conductivity of the Earth's surface and shallow subsurface media. One-dimensional geodetic conductivity parameters represent the Earth as composed of multiple horizontally layered structures, each layer with its own uniform conductivity value. These parameters characterize the vertical variation of conductivity across these layers. In areas with relatively simple geological structures and approximately horizontally layered distributions, geodetic conductivity parameters can effectively reflect the Earth's electrical conductivity. Considering the complexity of actual geological structures, geodetic conductivity is not uniformly distributed in three-dimensional space, exhibiting faults, overlapping of different rock layers, etc. Three-dimensional geodetic conductivity parameters are used to accurately describe the non-uniform variation of conductivity in three dimensions, better reflecting the actual conditions in complex geological environments. One-dimensional conductivity models are constructed based on one-dimensional geodetic conductivity parameters and are mathematical models used to characterize the electrical conductivity of the Earth with vertically layered structures. For example... Figure 3 As shown, the one-dimensional conductivity model simplifies the earth into multiple horizontal layers, assuming that the conductivity of each layer is uniform and varies only in the vertical direction, σ0, σ1, σ2...σ n Let h1, h2, ... h be the electrical conductivity of the surface layer, the first layer, the second layer... the nth layer of the earth, respectively; h1, h2... h n Z represents the height of the first floor, the second floor, ..., the nth floor; n This represents the wave impedance of the nth layer. For example... Figure 4 As shown, the three-dimensional conductivity model is established based on the three-dimensional earth conductivity parameters and is used to accurately describe the non-uniform variation of conductivity in three-dimensional space. Figure 4 γ in n This represents the earth's electrical conductivity. The division of different regions in the three-dimensional earth conductivity model in this figure is only for reference. As shown below... Figure 4 The shown figures represent the earth's electrical conductivity γ1, γ2, γ3, γ4, γ5, and γ6 for different regions. Actual regional division requires consideration of the local geological structure. By dividing the three-dimensional space into grids and assigning each grid cell a corresponding conductivity value, the electrical conductivity characteristics of the earth under complex geological structures can be simulated more realistically. The earth's electrical conductivity model is the final model formed by integrating one-dimensional or three-dimensional conductivity models. It is used to comprehensively describe the electrical conductivity characteristics of the earth in the area to be evaluated, providing key parameter support for subsequent calculations of the induced geoelectric field under geomagnetic disturbances.

[0074] In regions with relatively simple geological structures and approximately horizontal layered distributions, one-dimensional geodetic conductivity parameters can effectively describe the Earth's electrical conductivity. By incorporating these parameters, the Earth's electrical conductivity response at different frequency components can be considered. Based on these parameters, a conductivity model applicable to vertically layered Earth structures under specific frequency perturbations can be constructed, thus more accurately simulating the Earth's response to geomagnetic disturbances of different frequencies. For example, in plains areas with relatively homogeneous geological structures, a one-dimensional conductivity model can calculate the distribution of the induced electric field on the Earth's surface based on the conductivity and thickness of different geological layers and the frequency characteristics of geomagnetic disturbances, providing fundamental data for subsequent assessment of geomagnetic induced currents. However, in regions with complex geological structures, such as mountainous areas, areas with faults, or areas with mineral deposits, the Earth's conductivity exhibits non-uniform variations in three-dimensional space, and a one-dimensional conductivity model cannot accurately describe its electrical conductivity. At this point, by utilizing three-dimensional geoelectric conductivity parameters, the differences in conductivity in three-dimensional space and the influence of geomagnetic disturbances of different frequencies can be taken into account, thus constructing a three-dimensional conductivity model that better reflects actual geological conditions. This model can more accurately simulate the Earth's response to geomagnetic disturbances of different frequencies under complex geological structures, thereby improving the accuracy of induced geoelectric field calculations.

[0075] In a preferred embodiment of the present invention, based on the requirement of optimizing computational efficiency, a one-dimensional electrical structure model is constructed using the layered medium approximation theory by acquiring geodetic conductivity data at different depths in the region, thereby rapidly achieving parameterized characterization. The acquired one-dimensional geodetic conductivity model is then used to calculate wave impedance, and combined with the north-south and east-west components of the magnetic field, the north-south and east-west components of the induced ground electric field are calculated.

[0076] Traditional methods for constructing geodetic conductivity models often neglect the complexity of geological structures and the frequency characteristics of geomagnetic disturbances, leading to significant deviations between the models and actual conditions. This invention utilizes wavelet analysis and Fourier transform to deeply explore the time-frequency characteristics of geomagnetic disturbance data and combines one-dimensional and three-dimensional geodetic conductivity parameters to construct corresponding models for different geological structures. A one-dimensional model is used for simple geological structures, while a three-dimensional model is used for complex geological structures. Finally, the two models are combined to form a complete geodetic conductivity model, which can more accurately reflect the conductivity characteristics of the earth under geomagnetic disturbances at different frequencies. This significantly improves the model's fit with actual geological conditions and geomagnetic disturbance phenomena, thus providing a more reliable basis for subsequent calculations of induced geoelectric fields and geomagnetic induced currents, and significantly improving the accuracy of the evaluation results.

[0077] S3. Based on the geological structure of the power grid in the area to be evaluated, the geomagnetic disturbance data, and the earth conductivity model, calculate the induced geoelectric field under geomagnetic disturbance.

[0078] Preferably, the induced geoelectric field under geomagnetic disturbance is calculated based on the geological structure corresponding to the power grid in the area to be evaluated, the geomagnetic disturbance data, and the geoelectric conductivity model, including:

[0079] Wavelet analysis was performed on the magnetic field components in the geomagnetic disturbance data to obtain the first north-south component and the first east-west component used to characterize the magnetic field of the geomagnetic disturbance.

[0080] Fourier transforms are performed on the first north-south component and the first east-west component to obtain the second north-south component and the second east-west component, which are used to characterize the geomagnetic disturbance data in the frequency domain.

[0081] Based on the geological structure of the power grid in the area to be evaluated, determine the corresponding geoelectric conductivity model;

[0082] In the case of a horizontally layered geological structure, the depth and conductivity of each geological layer are determined based on a one-dimensional conductivity model.

[0083] The surface wave impedance is recursively calculated based on the preset vacuum permeability, preset angular frequency, depth of each geological layer, and conductivity.

[0084] The induced geoelectric field under geomagnetic disturbance is calculated based on the surface wave impedance, the preset angular frequency, and the preset magnetic field strength.

[0085] In the case of a non-horizontal layered geological structure, the conductivity distribution matrix of the grid cells and the geological structure boundary coordinates are extracted from the three-dimensional conductivity model.

[0086] Using the second north-south component and the second east-west component as boundary conditions, and based on the conductivity distribution matrix and the geological structure boundary coordinates, the finite element method is used to obtain the frequency domain induced geoelectric field spectrum data.

[0087] The induced geoelectric field under geomagnetic disturbance is obtained by performing discrete inverse Fourier transform on the frequency domain induced geoelectric field spectrum data.

[0088] Specifically, the geomagnetic disturbance data includes magnetic field components, which mainly contain data on the changes in magnetic field strength in the north-south and east-west directions. These data are key information reflecting the characteristics of geomagnetic disturbances, and their changes are closely related to the generation of geomagnetic induced currents. Wavelet analysis is performed on the magnetic field components in the geomagnetic disturbance data to obtain the first north-south component and the first east-west component, which characterize the geomagnetic disturbance magnetic field. Fourier transforms are then performed on the first north-south component and the first east-west component to obtain the second north-south component and the second east-west component, which characterize the geomagnetic disturbance data in the frequency domain. Wavelet analysis is a time-frequency analysis method that can decompose the magnetic field components in the geomagnetic disturbance data in both time and frequency dimensions.

[0089] Wavelet analysis can extract the characteristics of magnetic field variations across different time scales and frequency ranges, thus obtaining the first north-south component and the first east-west component to characterize the geomagnetic disturbance magnetic field, providing a foundation for subsequent frequency domain analysis. Fourier transform is a mathematical transformation method that converts a time-domain signal into a frequency-domain signal. Performing Fourier transforms on the first north-south component and the first east-west component obtained through wavelet analysis yields the second north-south component and the second east-west component of the geomagnetic disturbance data in the frequency domain, visually demonstrating the energy distribution of different frequency components within the entire geomagnetic disturbance signal.

[0090] In a preferred embodiment of the present invention, the magnetic field components in geomagnetic disturbance data often contain the superposition of multiple frequency components in the time domain, exhibiting complex variation characteristics. Wavelet analysis can analyze signals at different time scales, effectively extracting magnetic field variation information in different frequency bands, and decomposing the original magnetic field components into more characteristic first north-south components and first east-west components. This lays the foundation for a clearer analysis of the frequency characteristics of geomagnetic disturbances in the frequency domain and for constructing an accurate geodetic conductivity model. Wavelet analysis can highlight local variation characteristics in geomagnetic disturbance signals, such as rapidly changing geomagnetic pulse signals, which helps to capture the instantaneous characteristics of geomagnetic disturbances. Although the time-domain components obtained by wavelet analysis contain certain characteristic information, it is difficult to intuitively analyze the frequency components and energy distribution of the signal in the time domain. Fourier transform can convert the time-domain signal to the frequency domain, decomposing the geomagnetic disturbance signal into the superposition of sine and cosine waves of different frequencies, thereby obtaining the second north-south component and the second east-west component.

[0091] In a preferred embodiment of the present invention, wavelet analysis is used to decompose and analyze the obtained geomagnetic disturbance data. The wavelet analysis is shown in the formula: In the formula X DWT [i,j] represents the first north-south component and the first east-west component used to characterize the magnetic field of the geomagnetic disturbance, x[t] represents the input discrete signal, i.e., the magnetic field component in the geomagnetic disturbance data, and ψ i,j [t] represents the discrete wavelet function, where i is the scaling parameter, j is the translation parameter, and t represents the discrete-time index. Discrete wavelet functions are typically obtained from continuous wavelet functions through sampling and quantization.

[0092] In a preferred embodiment of the present invention, considering the accuracy and speed of calculating the induced geomagnetic field, the first north-south component and the first east-west component in the time domain are converted into frequency domain data using a Fast Fourier Transform (FFT), i.e., converted into the second north-south component and the second east-west component in the frequency domain to characterize the geomagnetic disturbance data, so that calculations can be performed in the frequency domain. By discretizing the time-domain data and applying a Fast Fourier Transform based on the Cooley-Tukey algorithm, the time-series signal is converted from the time domain to the frequency domain. The Cooley-Tukey algorithm decomposes a large Discrete Fourier Transform into multiple smaller Discrete Fourier Transforms and then recursively calculates these smaller Fourier Transforms. Its basic operational unit is the butterfly operation. For two complex numbers a and b, and a complex number W, the butterfly operation is defined by the formulas: a′=a+bW, b′=a-bW, where W represents the rotation factor. N represents the total number of sampling points of the signal. The mathematical expression for the Cooley-Tukey algorithm is shown in the formula: In the formula, N = n1·n2, where n1 and n2 are factors of N. x[l·n2+m] is a rearrangement of the input signal x[n], representing the decomposition of x[n] into n1 subsequences of length n2. The rotation factor represents the discrete Fourier transform of length n1. This represents the discrete Fourier twitch factor of length N. k represents the frequency index of the output, m is the index of the subsequence, and l represents the index within each subsequence.

[0093] Specifically, geological structure refers to the composition, distribution, and structural morphology of the underground rock, soil, and other media in the power grid area to be evaluated. It can be divided into horizontally layered structures (such as the regularly layered geological structures in plains) and non-horizontally layered structures (such as complex structures like faults and folds in mountainous areas). Its characteristics directly affect the Earth's response to magnetic field disturbances. Vacuum permeability describes the ability of a vacuum to conduct magnetic fields and is a fundamental parameter in computational electromagnetics. Angular frequency describes the rate of change; geomagnetic disturbances have different frequency components, and angular frequency is used to quantify these frequency characteristics to analyze the Earth's response to magnetic fields of different frequencies. Surface wave impedance is a physical quantity characterizing the Earth's resistance to electromagnetic wave propagation, reflecting the surface medium's ability to absorb and reflect electromagnetic field energy. It is related to the conductivity and thickness of the geological layer and the angular frequency of the magnetic field, and its magnitude affects the intensity and distribution of the induced ground electric field. Frequency-domain induced ground electric field spectrum data, obtained through finite element analysis, shows the intensity and phase information of the induced ground electric field at different frequency components, and is key data for analyzing the frequency characteristics of the induced ground electric field.

[0094] In a preferred embodiment of the present invention, the electrical conductivity of the earth varies significantly under different geological structures, and different models are needed to describe horizontal and non-horizontal layered structures. A one-dimensional conductivity model treats the earth as multiple horizontal layers, each with uniform conductivity and a specific thickness. Knowing the depth and conductivity of each layer is crucial for calculating the earth's response to magnetic field disturbances using electromagnetic theory. For example, a plain area may be divided into three layers; knowing the depth and conductivity of each layer allows for accurate calculation of the region's electromagnetic response. The surface wave impedance is recursively calculated based on a preset vacuum permeability, a preset angular frequency, the depth of each geological layer, and its conductivity. Surface wave impedance is a key intermediate parameter for calculating the induced electric field of the earth; its value depends on the earth's medium characteristics (conductivity, thickness) and the characteristics of magnetic field disturbances (angular frequency). Through recursive calculation, the combined effects of multiple media layers can be considered, yielding an accurate surface wave impedance value. The calculation is performed recursively from the bottom layer upwards, ultimately obtaining the surface wave impedance. Based on the skin effect and wave propagation theory in electromagnetism, there is a quantitative relationship between the Earth's surface wave impedance, angular frequency, and magnetic field strength and the induced ground electric field. Using known surface wave impedance and magnetic field strength, combined with the angular frequency, the induced ground electric field strength can be calculated. Transforming the Earth's electrical conductivity and magnetic field disturbance characteristics into the induced ground electric field results provides a driving force for subsequent calculations of geomagnetic induced current.

[0095] Non-horizontally layered geological structures present complex geological conditions with non-uniform electrical conductivity distribution in three-dimensional space. Finite element method (FEM) solutions require discretization of the geological structure. The conductivity distribution matrix and boundary coordinates are the fundamental inputs for constructing the FEM model, defining the medium properties and boundary conditions of the computational domain. The conductivity distribution matrix clarifies the conductivity characteristics of each grid cell, while the boundary coordinates determine the extent and shape of the computational domain. Together, they constitute the physical model for the FEM solution, ensuring that the calculation accurately reflects the actual geological structure. The north-south and east-west magnetic field components of geomagnetic disturbances are the excitation sources for the induced geoelectric field. By substituting the second north-south and second east-west components as boundary conditions into the FEM model, and combining the conductivity distribution and boundary coordinates, the induced geoelectric field distribution under complex geological structures can be numerically calculated. Since FEM solutions are typically performed in the frequency domain, frequency-domain induced geoelectric field spectrum data is obtained. For example, using FEM software, the magnetic field components are applied to the model boundaries, the conductivity distribution and boundary conditions are set, and Maxwell's equations are solved iteratively to obtain the induced geoelectric field intensity and phase data at each frequency, i.e., the frequency-domain induced geoelectric field spectrum data. Frequency-domain induced ground electric field spectrum data reflects the frequency characteristics of the induced ground electric field, but in practical applications, time-domain induced ground electric field data is needed to calculate geomagnetic induced current and assess its impact on the power grid. The inverse discrete Fourier transform (InFT) can convert frequency-domain data into a time-domain signal, obtaining the time-varying induced ground electric field. Through InFT, abstract frequency-domain data is transformed into an intuitive time-domain induced ground electric field curve, providing direct input for subsequent calculations of geomagnetic induced current using a power grid model, thus realizing a complete computational chain from geomagnetic disturbance to power grid response.

[0096] In a preferred embodiment of the present invention, the recursive method for solving the ground impedance at the ground surface includes the following: Based on the one-dimensional conductivity model, assuming the thickness of the nth layer is infinite, the wave impedance calculation formula for the nth layer is shown in the formula: In the formula k n σ represents the propagation constant. n Let μn represent the conductivity of the nth layer, μ0 represent the free magnetic permeability, and ω represent the angular frequency. Note that n is the layer number calculated from the bottom layer. The wave impedance relationship between the upper edges of the nth and (n+1)th layers in the one-dimensional conductivity model is given by the formula: In the formula h n k represents the height of the nth floor. n This represents the propagation constant of layer n. Combining the wave impedance relationship between the upper edges of layers n and n+1 in the one-dimensional conductivity model, recursive calculations can be performed to obtain the wave impedance of the top surface of each layer in the one-dimensional conductivity model. Furthermore, the wave impedance of the Earth's surface can be calculated. The calculation of the surface impedance provides data for the calculation of the induced ground electric field, as shown in the formula: Z0=f(w,σ1,σ2,…,σ n ,h1,h2,…,h n According to the formula: The data E(w) of the induced geoelectric field in the region under geomagnetic disturbance during the observation period can be obtained. Specifically, B(w) represents the magnetic field strength in the time domain, w represents the angular frequency, and Z(w) represents the wave impedance corresponding to different angular frequencies. Thus, when Z(w) is Z0, that is, when the wave impedance Z0 of the earth's surface is calculated, the data E(w) of the induced geoelectric field at the earth's surface can be calculated by substituting into the formula.

[0097] In a preferred embodiment of the present invention, because the frequency of changes in the induced geoelectric field during geomagnetic disturbances is low, the conduction current density on Earth is much greater than the displacement current density. Therefore, the magnetic field generated by the changes in the electric field can be neglected when calculating the Earth's electric field distribution. This can be achieved by introducing a vector magnetopotential. and scalar potential The field equations for solving eddy current field problems based on Maxwell's equations can be obtained, as shown in the formula: Based on this equation, the geoelectric field value at each location in the entire geodetic model can be calculated.

[0098] In the formula, This represents a vector differential operator used to describe field quantities (such as scalar potential). The spatial variation characteristics of ); μ represents magnetic permeability, approximated by its vacuum value, σ represents the electrical conductivity of the Earth, J s The equivalent current density within the solution domain is represented by J, which is set to 0 since there is no current source within the solution domain. Based on a three-dimensional non-uniform earth conductivity structure model, a high-order finite element discretization method combined with unstructured mesh generation technology is used. Under the quasi-static electromagnetic field approximation condition, a high-precision numerical simulation of the spatial distribution of the induced ground electric field at the regional scale is achieved by solving the coupled Maxwell-Ohm partial differential equations and applying boundary conditions. Since the obtained induced ground electric field is frequency domain data, an inverse Fourier transform is required to convert the frequency domain induced ground electric field data into time domain data. The calculated induced ground electric field data is processed and output to provide data support for the calculation of geomagnetic induced current. By performing a discrete inverse Fourier transform operation on the frequency domain induced ground electric field spectrum data, the electric field quantity is reconstructed from the frequency domain to the time domain, as shown in the formula: In the formula E(t) n E(w) represents the electric field time-domain signal. k ) represents the electric field frequency domain signal, N represents the total number of signal sampling points, and k represents the frequency index. IDFT represents the inverse discrete Fourier transform.

[0099] For horizontally layered structures, the recursive calculation based on a one-dimensional model strictly follows electromagnetic theory, considering the combined effects of multiple media. For non-horizontally layered structures, the finite element method, through discretization and numerical calculation, accurately handles non-uniform conductivity distribution and complex boundary conditions. Combining these two methods ensures accurate induced geoelectric field results under different geological conditions, providing reliable data support for subsequent geomagnetic induced current assessments and enhancing the credibility and practicality of the entire assessment method.

[0100] S4. Based on the power grid topology data and the power grid equipment configuration parameters, construct a regional power grid node simulation model;

[0101] Preferably, the power grid equipment configuration parameters include voltage level, transformer winding connection method, and transformer combination method;

[0102] Based on the power grid topology data and the power grid equipment configuration parameters, a regional power grid node simulation model is constructed, including:

[0103] The power grid in the area to be evaluated is divided into different voltage levels according to the voltage level; the busbars and transformers in each voltage level are regarded as nodes.

[0104] Based on the power grid topology data, the relationships between nodes and lines in different voltage levels are established, and a topology correlation matrix is ​​obtained.

[0105] Construct the equivalent circuit of the transformer based on the transformer winding connection method and the transformer combination method;

[0106] Based on the topological correlation matrix, the equivalent circuit of the transformer is embedded in the initial node admittance matrix to obtain the simulation model of the regional power grid nodes; where the initial node admittance matrix represents the line admittance between different nodes.

[0107] Specifically, the transformer winding connection method represents the wiring configuration of the primary and secondary windings of the transformer. Common types include: Yyn0 (star-star, neutral grounded); Yd11 (star-delta, 30° phase angle offset); Dyn11 (delta-star), etc. Different connection methods directly affect the zero-sequence current path and phase angle relationship. The transformer combination method represents the connection and operation mode of multiple transformers, including parallel (capacity superposition), series (voltage level conversion), or mixed combination, affecting the equivalent impedance and power distribution of the power grid. The topology correlation matrix is ​​a mathematical matrix describing the connection relationship between power grid nodes and lines. The initial node admittance matrix contains only the admittance parameters of transmission lines and is used to describe the electrical connection characteristics of lines between nodes, forming the basic framework for constructing a complete power grid model.

[0108] In a preferred embodiment of the present invention, large-scale power grids have diverse voltage levels. Layered processing reduces modeling complexity and facilitates matching equipment parameters (such as insulation level and short-circuit capacity) according to voltage levels. The power grid is abstracted into a multi-level structure, with nodes (buses, transformers) within each voltage level having the same voltage reference, simplifying electromagnetic coupling calculations across voltage levels. The topology correlation matrix quantifies the physical connections of the power grid through mathematical matrices, providing a topological foundation for subsequent admittance matrix construction. The correlation matrix can be directly mapped to the node-branch connection relationships in circuit equations and is the core topology data structure for power grid simulation. The transformer winding connection method and combination method directly affect its electromagnetic characteristics (such as phase angle offset and zero-sequence impedance), requiring accurate characterization through the construction of an equivalent transformer circuit. For the Yyn0 connected transformer, a T-type equivalent circuit with neutral point grounding impedance is constructed; for the Yd11 connected transformer, a 30° phase angle offset matrix is ​​included, and the zero-sequence impedance is set to infinity. Figure 5 As shown, the initial admittance matrix only contains the line admittance, and the transformer equivalent admittance needs to be superimposed to fully characterize the electrical characteristics of the power grid. The locations of the nodes at both ends of the transformer are determined by the topological correlation matrix, and the equivalent admittance matrix is ​​embedded into the corresponding sub-blocks of the initial admittance matrix to form a complete regional power grid node simulation model. Figure 5 It includes nodes m, n, p, q, i and k, y mi y represents the admittance of the line between node m and node i; pi y represents the admittance of the line between node p and node i; ik y represents the admittance of the line between node i and node k; kn This represents the admittance of the line between node k and node n; y kq y represents the admittance of the line between node k and node q; i Represents the ground admittance of node i; y k Represents the ground admittance of node k; j mi This represents the equivalent current source between node m and node i; j ik This represents the equivalent current source between node i and node k; j kn This represents the equivalent current source between node k and node n.

[0109] In a preferred embodiment of the present invention, under strong geomagnetic disturbance conditions, the quasi-electrostatic field induced by the time-varying magnetic field on the Earth's surface serves as the primary excitation source, inducing current in a closed loop formed by the power grid conductors, transformer grounding devices, and underground conductive layers. This electromagnetic coupling process can be represented in the transmission network model as a system of parallel distributed equivalent potential sources using equivalent circuit theory. Its strength depends on the interaction between the spatial distribution of the regional geoelectric field and the transmission line alignment. Based on geomagnetic station observation data, by solving the quasi-static electromagnetic field equations and combining them with a three-dimensional geoelectric structure model for numerical calculation, the spatiotemporal distribution characteristics of the induced electric field in the target area can be accurately inverted. Then, the equivalent excitation source parameters for each transmission line segment can be determined using the line path integration method. For the power grid area requiring extreme geomagnetic induced current calculations, relevant structural parameters of the regional power grid are obtained, including voltage levels, the topology of the regional power grid circuits, transformer winding connection methods, and transformer combination methods. A full-node model, i.e., a regional power grid node simulation model, is then used to calculate the geomagnetic induced current.

[0110] The construction of the full-node model (regional power grid node simulation model) is based on the following principles. Corresponding computational nodes are set for the regional power grid, with all busbars and neutral points of each substation in the power grid network designated as nodes. Neutral nodes without DC blocking devices are designated as grounded nodes. In the full-node model built according to this principle, transmission lines are branches of busbar nodes at the same voltage level, and transformer windings are branches of busbar nodes at different voltage levels and branches between busbar nodes and neutral nodes. The connection methods of the three-phase windings of the transformer are usually star connection and delta connection. For star-connected transformers, provided the neutral node is grounded, the busbar node and neutral node can be set as independent nodes. For delta-connected transformers, the quasi-DC geomagnetic induced current does not have flow characteristics, and the busbar node connected to it can be ignored. The existence of the transformer makes it possible for the geomagnetic induced current to flow in the power grid; the flow path of the geomagnetic induced current in the transformer is related to the transformer's connection group. When ordinary transformers are connected in parallel, they form three branches: the high-voltage busbar and neutral point branch, the low-voltage busbar and neutral point branch, and the neutral point and ground branch. When autotransformers are connected in parallel, they form three branches: the high-voltage busbar and low-voltage busbar branch, the low-voltage busbar and neutral point branch, and the neutral point and ground branch. When ordinary transformers and autotransformers are connected in a mixed manner, they form four branches: the high-voltage busbar and low-voltage busbar branch, the high-voltage busbar and neutral point branch, the low-voltage busbar and neutral point branch, and the neutral point and ground branch.

[0111] S5. Based on the simulation model of the regional power grid nodes and the induced geoelectric field, calculate the geomagnetic induced current distribution of each node of the power grid in the region to be evaluated under the geomagnetic storm event.

[0112] Preferably, based on the regional power grid node simulation model and the induced geoelectric field, the geomagnetic induced current distribution of each node in the power grid to be evaluated under a geomagnetic storm event is calculated, including:

[0113] The time-domain signal of the electric field is obtained by performing an inverse discrete Fourier transform operation on the induced ground electric field.

[0114] The electric field time-domain signal is mapped to both ends of the line in the simulation model of the regional power grid nodes, and the equivalent electromotive force between the nodes is calculated.

[0115] The total current source flowing into each node is calculated based on the equivalent electromotive force between nodes and the line admittance in the simulation model of the regional power grid nodes.

[0116] The voltage of each node is calculated based on the total current source flowing into each node and the node admittance matrix corresponding to the simulation model of the regional power grid nodes.

[0117] The geomagnetic induced current between each node is calculated based on the voltage of each node, the total current source flowing into each node, and the line admittance.

[0118] Based on the geomagnetic induced current between nodes, the distribution of geomagnetic induced current at each node of the power grid in the area to be evaluated under a geomagnetic storm event is obtained.

[0119] Specifically, the Inverse Discrete Fourier Transform (IDFT) is a mathematical operation that converts a frequency-domain signal into a time-domain signal. In this invention, it is used to convert the frequency-domain induced ground electric field calculated through the earth conductivity model into a time-varying signal to match the time-domain characteristics of the power grid node model. The equivalent electromotive force (EMF) represents the voltage difference generated by the induced ground electric field at both ends of the transmission line as an equivalent EMF source in the circuit model, and is a key physical quantity coupling the ground electric field and the power grid model. The total current source flowing into a node is the total current excitation flowing into that node after considering the equivalent EMF and admittance of all lines connected to the node, measured in amperes (A), and is used to drive the solution of the node voltage equation. The node admittance matrix describes the electrical connection relationships between power grid nodes; the element values ​​represent the admittance parameters between nodes, and it is the core mathematical model for power system simulation. The geomagnetically induced current (GIC) represents the DC or low-frequency current generated in the power grid during geomagnetic storms, mainly flowing through the transformer neutral point, which may lead to equipment magnetic saturation and protection malfunctions.

[0120] In a preferred embodiment of the present invention, the induced ground electric field is typically in the frequency domain (e.g., obtained by solving the frequency domain spectrum data using the finite element method), while the power grid node model requires time-domain excitation for dynamic simulation. Therefore, IDFT transformation is necessary to convert the frequency-domain electric field signal into a time-domain signal, i.e., the electric field time-domain signal. The induced electromotive force generated by the ground electric field in the transmission line is the driving source of the geomagnetic induced current (GIC). The spatially distributed electric field needs to be converted into an electromotive force source in the circuit model. By integrating along the line path, the electric field strength is converted into the voltage difference between the two ends of the line. According to circuit theory, the electromotive force needs to be converted into a node-injected current source before it can be incorporated into the node admittance matrix equation. The node admittance matrix equation is the basis for the steady-state analysis of the power grid. Solving this equation yields the voltage of each node. When the node voltage and line admittance are known, the line current, i.e., the GIC distribution, can be calculated using Ohm's law. The currents of each line are aggregated to the nodes, forming the GIC distribution of the entire network, providing complete data for risk assessment. By traversing all line currents and statistically analyzing the inflow / outflow current of each node, the GIC intensity of each node in the power grid, i.e., the geomagnetic induced current distribution of each node, can be obtained.

[0121] Indicatively, it also includes: conducting a system sensitivity analysis of the power grid in the area to be evaluated for a specific geomagnetic storm time based on the distribution of geomagnetic induced currents at each node of the power grid in the area to be evaluated;

[0122] Based on the number of adjacent nodes of each node in the power grid topology data, the geomagnetic induced current of each node, and the preset node weight, the sensitivity of each node to the geomagnetic induced current is calculated.

[0123] Based on the sensitivity of each node to geomagnetic induced current and the preset sensitivity threshold, the risk levels of each node in the power grid of the area to be evaluated are classified.

[0124] In a preferred embodiment of the present invention, the number of adjacent nodes represents the number of lines directly connected to a node in the power grid topology, reflecting the topological importance of the node in the power grid (e.g., hub nodes usually have a large number of adjacent nodes). The preset node weight represents a weighting coefficient set according to factors such as node voltage level and equipment importance. Sensitivity is used to quantify the comprehensive index of a node's response to geomagnetic induced current (GIC), integrating GIC amplitude, topological importance, and equipment weight. A municipal power grid contains 35 220kV nodes and 89 110kV nodes. GIC assessment is performed after a Kp=5 geomagnetic storm. Node A (220kV, number of adjacent nodes = 4, weight = 0.6) has a GIC of 5.5A and a sensitivity SA of 0.5*5.5 + 0.3*4 + 0.2*0.6 = 3.97. Node B (110kV, adjacency count = 2, weight = 0.3) has a GIC of 2.1A and a sensitivity SB of 0.5*2.1 + 0.3*2 + 0.2*0.3 = 1.53. With a threshold of 0.7 / 0.3, Node A is considered high-risk, and Node B is considered medium-risk.

[0125] Schematably, it also includes: generating a node geomagnetic induced current heat map to characterize the distribution of geomagnetic induced currents at each node of the regional power grid based on the geomagnetic induced currents between each node.

[0126] The geographic coordinates corresponding to the geomagnetic induced current heat map of the node are matched with the electrical node coordinates corresponding to the regional power grid node simulation model to determine the mapping relationship between geographic and electrical coordinates.

[0127] Based on the mapping relationship between geographic and electrical coordinates, the geomagnetic induced current heat map of the nodes and the simulation model of the regional power grid nodes are superimposed, and each node is marked according to its risk level to obtain a visualized image of the regional power grid's response to geomagnetic storm events.

[0128] In a preferred embodiment of the present invention, the nodal geomagnetic induced current heatmap visually displays a two-dimensional image of the amplitude of the nodal geomagnetic induced current using color gradients (such as red and blue), with color depth representing current intensity. Geographic coordinates represent the latitude and longitude of the node on the Earth's surface. Electrical node coordinates represent the abstract coordinates of the node in the power grid model (such as (x,y) coordinates in a two-dimensional plane), used to describe topological relationships. The regional power grid response visualization image under geomagnetic storm events integrates the comprehensive visualization results of geographical background, power grid topology, and GIC risk, supporting interactive queries. Traditional data reports are difficult to present risk distribution intuitively; the response visualization image makes high-risk areas immediately apparent. For example, a concentration of red nodes in a region's heatmap indicates the coupling risk between geological structures and power grid topology. During geomagnetic storms, dispatchers can quickly locate fault sources (such as a red node tripping) through the visualization image, shortening fault handling time. In power grid expansion planning, the heatmap can be analyzed to avoid areas with high geomagnetic induced current risk. For example, when selecting a site for a new substation, visualization can reveal that the candidate site is located in a red area of ​​the heatmap, thus adjusting the site selection. A visual assessment of a provincial power grid's response to a super geomagnetic storm (Kp=9) in a specific month and year: Of the 432 nodes in the entire network, 87 nodes had a GIC ≥ 7A (red), and 156 nodes had a GIC ≥ 7A (yellow). The node numbers in the electrical model were matched with the GPS coordinates of substations. Heatmaps and the power grid topology were overlaid on a WebGIS platform. High-risk nodes were labeled "red triangle + geomagnetic induced current = 8.5A + high risk." Maintenance personnel prioritized handling red nodes through the visual image to avoid transformer saturation accidents. Multi-dimensional visualization technology was used to graphically represent the calculation results. A spatial topology mapping was constructed using a geographic information system platform, overlaying the geomagnetic induction intensity of regional power grid nodes as a heatmap onto the power grid architecture. Simultaneously, time series analysis was used to display the dynamic evolution characteristics of the geomagnetic induced current at key nodes, and 3D rendering technology was introduced to visualize the spatial distribution of the transformer neutral point current vector.

[0129] By implementing this embodiment, multi-dimensional data evaluation is achieved through geomagnetic disturbance data, earth conductivity data, power grid topology data, and power grid equipment configuration parameters. Simultaneously, the earth conductivity data is adapted to different geological structures, resolving the calculation deviation of the induced geoelectric field caused by geological differences. This provides a data foundation for scenarios where geological conditions and power grid structure interact in large-scale power grids. An earth conductivity model is constructed based on geomagnetic disturbance data and earth conductivity data. The induced geoelectric field is calculated in conjunction with the geological structure of the power grid in the area to be evaluated. Simultaneously, a regional power grid node simulation model is constructed based on the power grid topology and equipment configuration parameters. This fully considers the complexity of geological structures and the diversity of power grid topologies, changing the situation in traditional evaluations where model simplification leads to distortion of the actual situation. It can more realistically simulate the physical processes of the power grid under geomagnetic disturbances. Through the collaborative calculation of the regional power grid node simulation model and the induced geoelectric field, the distribution of geomagnetic induced current at each node of the regional power grid under geomagnetic storm events can be accurately obtained. This multi-model coupled calculation method effectively overcomes the shortcomings of traditional assessment methods in adapting to complex power grids, enabling assessment results to penetrate all nodes of the power grid and cover the entire region, achieving a refined assessment of the impact of extreme geomagnetic induced currents, thereby ensuring the safe and stable operation of large-scale high-voltage power grids under geomagnetic disturbances.

[0130] See Figure 6 This is a schematic diagram of the structure of an extreme geomagnetic induced current assessment device based on a regional power grid, provided in an embodiment of the present invention, comprising:

[0131] The power grid data acquisition module is used to acquire geomagnetic disturbance data, geodetic conductivity data of the geomagnetic induced current area, power grid topology data, and power grid equipment configuration parameters of the power grid in the area to be evaluated.

[0132] The conductivity model construction module is used to construct a ground conductivity model based on the ground conductivity data.

[0133] The induced geoelectric field calculation module is used to calculate the induced geoelectric field under geomagnetic disturbance based on the geological structure corresponding to the power grid in the area to be evaluated, the geomagnetic disturbance data, and the earth conductivity model.

[0134] The node simulation model construction module is used to construct a regional power grid node simulation model based on the power grid topology data and the power grid equipment configuration parameters.

[0135] The geomagnetic induced current assessment module is used to calculate the geomagnetic induced current distribution of each node of the power grid in the area to be assessed under a geomagnetic storm event, based on the simulation model of the regional power grid nodes and the induced geoelectric field.

[0136] This invention provides an extreme geomagnetic induced current assessment device based on a regional power grid. The device acquires geomagnetic disturbance data from various geomagnetic observatories in the region to be assessed, geodetic conductivity data of the geomagnetic induced current region, power grid topology data, and power grid equipment configuration parameters using a power grid data acquisition module. In a conductivity model construction module, a geodetic conductivity model is constructed based on the geodetic conductivity data. In an induced geoelectric field calculation module, the induced geoelectric field under geomagnetic disturbance is calculated based on the geological structure corresponding to the power grid in the region to be assessed, the geomagnetic disturbance data, and the geodetic conductivity model. In a node simulation model construction module, a regional power grid node simulation model is constructed based on the power grid topology data and the power grid equipment configuration parameters. Finally, in a geomagnetic induced current assessment module, the geomagnetic induced current distribution of each node in the regional power grid under a geomagnetic storm event is calculated based on the regional power grid node simulation model and the induced geoelectric field.

[0137] By utilizing geomagnetic disturbance data, earth conductivity data, power grid topology data, and power grid equipment configuration parameters, multi-dimensional data evaluation is achieved. Furthermore, the earth conductivity data is adapted to different geological structures, resolving calculation errors in the induced geoelectric field caused by geological differences. This provides a data foundation for scenarios where geological conditions and power grid structure interact in large-scale power grids. An earth conductivity model is constructed based on the earth conductivity data, and the induced geoelectric field is calculated in conjunction with the geological structure of the power grid in the area to be evaluated. Simultaneously, a regional power grid node simulation model is built based on the power grid topology and equipment configuration parameters, fully considering the complexity of geological structures and the diversity of power grid topologies. This overcomes the distortion of actual conditions caused by model simplification in traditional evaluations, enabling a more realistic simulation of the physical processes of the power grid under geomagnetic disturbances. Through the collaborative calculation of the regional power grid node simulation model and the induced geoelectric field, the distribution of geomagnetically induced currents at each node of the regional power grid under geomagnetic storm events can be accurately obtained. This multi-model coupled calculation method effectively overcomes the shortcomings of traditional assessment methods in adapting to complex power grids, enabling assessment results to penetrate all nodes of the power grid and cover the entire region, achieving a refined assessment of the impact of extreme geomagnetic induced currents, thereby ensuring the safe and stable operation of large-scale high-voltage power grids under geomagnetic disturbances.

[0138] It should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0139] Those skilled in the art will understand that, for convenience and brevity, the specific working process of the device described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0140] Another embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements a method for assessing extreme geomagnetic induced current based on a regional power grid as described in the above embodiments. The terminal device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0141] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting various parts of the terminal device via various interfaces and lines.

[0142] The memory can be used to store the computer program. The processor implements various functions of the terminal device by running or executing the computer program stored in the memory and calling data stored in the memory. The memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function, etc.; the data storage area may store data created based on the use of the mobile phone, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0143] Another embodiment of the present invention provides a computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to perform the extreme geomagnetic induced current assessment method based on a regional power grid as described in the above embodiment.

[0144] The storage medium is a computer-readable storage medium, and the computer program is stored in the computer-readable storage medium. When executed by a processor, the computer program can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0145] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for assessing extreme geomagnetic induced current based on a regional power grid, characterized in that, include: Obtain geomagnetic disturbance data, geodetic conductivity data of geomagnetic induced current areas, power grid topology data, and power grid equipment configuration parameters from various geomagnetic stations in the power grid to be evaluated area. Based on the aforementioned earth conductivity data, an earth conductivity model is constructed. Based on the geological structure of the power grid in the area to be evaluated, the geomagnetic disturbance data, and the earth conductivity model, the induced geoelectric field under geomagnetic disturbance is calculated. Based on the power grid topology data and the power grid equipment configuration parameters, a regional power grid node simulation model is constructed. Based on the regional power grid node simulation model and the induced geoelectric field, the geomagnetic induced current distribution of each node in the regional power grid to be evaluated under a geomagnetic storm event is calculated.

2. The method for assessing extreme geomagnetic induced current based on a regional power grid as described in claim 1, characterized in that, The earth conductivity data includes: a one-dimensional earth conductivity parameter used to characterize the vertical stratification of conductivity, and a three-dimensional earth conductivity parameter used to characterize the non-uniform variation of conductivity in three dimensions. Based on the aforementioned earth conductivity data, an earth conductivity model is constructed, including: Based on the one-dimensional earth conductivity parameters, a one-dimensional conductivity model is constructed to characterize the vertical stratification structure. Based on the three-dimensional earth conductivity parameters, a three-dimensional conductivity model is constructed to characterize three-dimensional non-uniform structures. One-dimensional or three-dimensional conductivity models are used as models of earth conductivity.

3. The method for assessing extreme geomagnetic induced current based on a regional power grid as described in claim 2, characterized in that, The geomagnetic disturbance data includes magnetic field components; Based on the geological structure of the power grid area to be evaluated, the geomagnetic disturbance data, and the earth conductivity model, the induced geoelectric field under geomagnetic disturbance is calculated, including: Wavelet analysis was performed on the magnetic field components in the geomagnetic disturbance data to obtain the first north-south component and the first east-west component used to characterize the magnetic field of the geomagnetic disturbance. Fourier transforms are performed on the first north-south component and the first east-west component to obtain the second north-south component and the second east-west component, which are used to characterize the geomagnetic disturbance data in the frequency domain. Based on the geological structure of the power grid in the area to be evaluated, determine the corresponding geoelectric conductivity model; In the case of a horizontally layered geological structure, the depth and conductivity of each geological layer are determined based on a one-dimensional conductivity model. The surface wave impedance is recursively calculated based on the preset vacuum permeability, preset angular frequency, depth of each geological layer, and conductivity. The induced geoelectric field under geomagnetic disturbance is calculated based on the surface wave impedance, the preset angular frequency, and the preset magnetic field strength. In the case of a non-horizontal layered geological structure, the conductivity distribution matrix of the grid cells and the geological structure boundary coordinates are extracted from the three-dimensional conductivity model. Using the second north-south component and the second east-west component as boundary conditions, and based on the conductivity distribution matrix and the geological structure boundary coordinates, the finite element method is used to obtain the frequency domain induced geoelectric field spectrum data. The induced geoelectric field under geomagnetic disturbance is obtained by performing discrete inverse Fourier transform on the frequency domain induced geoelectric field spectrum data.

4. The method for assessing extreme geomagnetic induced current based on a regional power grid as described in claim 1, characterized in that, The power grid equipment configuration parameters include voltage level, transformer winding connection method, and transformer combination method; Based on the power grid topology data and the power grid equipment configuration parameters, a regional power grid node simulation model is constructed, including: The power grid in the area to be evaluated is divided into different voltage levels according to the voltage level; the busbars and transformers in each voltage level are regarded as nodes. Based on the power grid topology data, the relationships between nodes and lines in different voltage levels are established, and a topology correlation matrix is ​​obtained. Construct the equivalent circuit of the transformer based on the transformer winding connection method and the transformer combination method; Based on the topological correlation matrix, the equivalent circuit of the transformer is embedded in the initial node admittance matrix to obtain the simulation model of the regional power grid nodes; where the initial node admittance matrix represents the line admittance between different nodes.

5. The method for assessing extreme geomagnetic induced current based on a regional power grid as described in claim 1, characterized in that, Based on the regional power grid node simulation model and the induced geoelectric field, the geomagnetic induced current distribution of each node in the power grid to be evaluated under a geomagnetic storm event is calculated, including: The time-domain signal of the electric field is obtained by performing an inverse discrete Fourier transform operation on the induced ground electric field. The electric field time-domain signal is mapped to both ends of the line in the simulation model of the regional power grid nodes, and the equivalent electromotive force between the nodes is calculated. The total current source flowing into each node is calculated based on the equivalent electromotive force between nodes and the line admittance in the simulation model of the regional power grid nodes. The voltage of each node is calculated based on the total current source flowing into each node and the node admittance matrix corresponding to the simulation model of the regional power grid nodes. The geomagnetic induced current between each node is calculated based on the voltage of each node, the total current source flowing into each node, and the line admittance. Based on the geomagnetic induced current between nodes, the distribution of geomagnetic induced current at each node of the power grid in the area to be evaluated under a geomagnetic storm event is obtained.

6. The method for assessing extreme geomagnetic induced current based on a regional power grid as described in claim 5, characterized in that, Also includes: Based on the distribution of geomagnetic induced current at each node of the power grid in the area to be evaluated, a system sensitivity analysis of the power grid in the area to be evaluated is conducted for a specific geomagnetic storm time. Based on the number of adjacent nodes of each node in the power grid topology data, the geomagnetic induced current of each node, and the preset node weight, the sensitivity of each node to the geomagnetic induced current is calculated. Based on the sensitivity of each node to geomagnetic induced current and the preset sensitivity threshold, the risk levels of each node in the power grid of the area to be evaluated are classified.

7. The method for assessing extreme geomagnetic induced current based on a regional power grid as described in claim 6, characterized in that, Also includes: Based on the geomagnetic induced current between each node, a node geomagnetic induced current heat map is generated to characterize the distribution of geomagnetic induced current at each node of the regional power grid. The geographic coordinates corresponding to the geomagnetic induced current heat map of the node are matched with the electrical node coordinates corresponding to the regional power grid node simulation model to determine the mapping relationship between geographic and electrical coordinates. Based on the mapping relationship between geographic and electrical coordinates, the geomagnetic induced current heat map of the nodes and the simulation model of the regional power grid nodes are superimposed, and each node is marked according to its risk level to obtain a visualized image of the regional power grid's response to geomagnetic storm events.

8. An extreme geomagnetic induced current assessment device based on a regional power grid, characterized in that, include: The power grid data acquisition module is used to acquire geomagnetic disturbance data, geodetic conductivity data of the geomagnetic induced current area, power grid topology data, and power grid equipment configuration parameters of the power grid in the area to be evaluated. The conductivity model construction module is used to construct a ground conductivity model based on the ground conductivity data. The induced geoelectric field calculation module is used to calculate the induced geoelectric field under geomagnetic disturbance based on the geological structure corresponding to the power grid in the area to be evaluated, the geomagnetic disturbance data, and the earth conductivity model. The node simulation model construction module is used to construct a regional power grid node simulation model based on the power grid topology data and the power grid equipment configuration parameters. The geomagnetic induced current assessment module is used to calculate the geomagnetic induced current distribution of each node of the power grid in the area to be assessed under a geomagnetic storm event, based on the simulation model of the regional power grid nodes and the induced geoelectric field.

9. A terminal device, characterized in that, The system includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements a method for assessing extreme geomagnetic induced current based on a regional power grid as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored computer program, wherein, when the computer program is executed, it controls the device containing the computer-readable storage medium to perform an extreme geomagnetic induced current assessment method based on a regional power grid as described in any one of claims 1 to 7.

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