Method and device for calculating impulse impedance of grounding grid and computer equipment
Patent Information
- Application Number
- CN202610936038.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-26
- Publication Date
- 2026-10-13
AI Technical Summary
[0009]借由上述技术方案，本申请实施例提供的一种接地网的冲击阻抗计算方法、装置及计算机设备，通过获取包括电磁场模型与电路模型的三维仿真模型，并结合电磁场模型与电路模型开展联合计算，将雷电流幅值分步代入求解瞬时电流、空间电位及等效电流。之后在目标时刻的雷电流瞬时值与目标时刻的目标等效电流之间的差值处于预设误差范围内的情况下，由注入节点电位最大值与雷电流瞬时峰值比值得到峰值冲击阻抗。这样，可以有效兼顾电磁场分布特性与电路传输特性，大幅提升冲击阻抗的计算精度，能够真实反映雷电流激励下接地网的暂态工作状态，可为接地网防雷设计、安全评估及运维改造提供准确可靠的数据依据。
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Abstract
Description
Technical Field
[0001] This application relates to the field of power system grounding technology, and in particular to a method, apparatus and computer equipment for calculating the impulse impedance of a grounding grid. Background Technology
[0002] Lightning is one of the major natural disasters threatening the safe and stable operation of power systems. When lightning current enters the grounding grid, it will produce significant transient electromagnetic effects. The grounding grid impulse impedance, as the core parameter characterizing its transient leakage and potential distribution characteristics, directly determines the insulation safety of electrical equipment, personal safety, and the overall level of lightning protection.
[0003] Therefore, how to accurately calculate the impulse impedance in order to improve the lightning protection level and operational reliability of the power system has become an urgent problem to be solved. Summary of the Invention
[0004] In view of this, embodiments of this application provide a method, apparatus, and computer equipment for calculating the impulse impedance of a grounding grid, which can achieve accurate calculation of impulse impedance, thereby improving the lightning protection level and operational reliability of the power system.
[0005] Firstly, this application provides a method for calculating the impulse impedance of a grounding grid, including: Obtain a three-dimensional simulation model of the grounding grid; the three-dimensional simulation model includes an electromagnetic field model and a circuit model, and the electromagnetic field model consists of a grounding grid conductor model and a soil domain model; The amplitude of the lightning current is input into the electromagnetic field model to obtain the instantaneous value of the lightning current and the global spatial potential at the target time. The instantaneous value of the lightning current and the global space potential at the target time are input into the circuit model to obtain the target equivalent current at the target time. If the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within the preset error range, the ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current is determined as the peak impulse impedance of the grounding grid; where the injected node potential refers to the ground potential corresponding to the circuit node in the circuit model where the lightning current is injected.
[0006] Secondly, this application provides a device for calculating the impulse impedance of a grounding grid, comprising: The model acquisition module is used to acquire a three-dimensional simulation model of the grounding grid; the three-dimensional simulation model includes an electromagnetic field model and a circuit model, and the electromagnetic field model consists of a grounding grid conductor model and a soil domain model. The data output module is used to input the current amplitude of the lightning current into the electromagnetic field model to obtain the instantaneous value of the lightning current and the global spatial potential at the target time. The current output module is used to input the instantaneous value of the lightning current and the global space potential at the target time into the circuit model to obtain the target equivalent current at the target time. The impedance calculation module is used to determine the ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current as the peak impulse impedance of the grounding grid, provided that the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range. Here, the injected node potential refers to the ground potential corresponding to the circuit node in the circuit model where the lightning current is injected.
[0007] Thirdly, this application provides a storage medium storing a computer program thereon, which, when executed by a processor, implements the above-mentioned method for calculating the impulse impedance of the grounding grid.
[0008] Fourthly, this application provides a computer device, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor executes the program to implement the above-mentioned method for calculating the impulse impedance of the grounding grid.
[0009] By employing the above technical solutions, the embodiments of this application provide a method, apparatus, and computer equipment for calculating the impulse impedance of a grounding grid. This method acquires a three-dimensional simulation model including an electromagnetic field model and a circuit model, and performs joint calculations by combining the electromagnetic field model and the circuit model. The lightning current amplitude is substituted step-by-step to solve for the instantaneous current, space potential, and equivalent current. Then, provided that the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range, the peak impulse impedance is obtained from the ratio of the maximum value of the injected node potential to the instantaneous peak value of the lightning current. This effectively balances the electromagnetic field distribution characteristics and circuit transmission characteristics, significantly improving the calculation accuracy of the impulse impedance. It can accurately reflect the transient operating state of the grounding grid under lightning current excitation, providing accurate and reliable data for grounding grid lightning protection design, safety assessment, and operation and maintenance upgrades.
[0010] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description
[0011] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A schematic flowchart of a method for calculating the impulse impedance of a grounding grid according to an embodiment of this application is shown. Figure 2 A flowchart illustrating another method for calculating the impulse impedance of a grounding grid provided in an embodiment of this application is shown. Figure 3 A schematic diagram of the structure of a grounding grid impulse impedance calculation device provided in an embodiment of this application is shown. Detailed Implementation
[0012] To facilitate the explanation of the embodiments of this application, some technical terms and technical means related to the embodiments of this application, as well as the application scenarios of the embodiments of this application, will be introduced first below.
[0013] As a key component for the safe operation of power systems and electrical equipment, the grounding grid's impulse impedance describes the impedance characteristics of the grounding system under transient current. Its physical nature reflects the grounding device's ability to dissipate high-frequency transient currents. The impulse impedance characteristics of the grounding grid directly determine the transient response performance during lightning strikes or short-circuit faults. It is a core parameter for characterizing the level of overvoltage suffered by electrical equipment and evaluating the effectiveness of lightning protection.
[0014] In some cases, the impulse impedance of the grounding grid at each frequency point is calculated using Fourier transform combined with the method of moments or the nodal voltage method, and then the impulse impedance of the grounding grid at each frequency point is inverted in the time domain to obtain the transient impulse impedance in the time domain. This not only leads to a sharp increase in the amount of calculation due to the bandwidth expansion, but also makes the calculation results susceptible to the influence of soil structure parameters, making the implementation in engineering more complicated.
[0015] In other cases, segmented circuits are constructed using tools such as the Electromagnetic Transient Simulation Program (ATP-EMTP) to simulate the nonlinear changes in soil spark effects in the time domain. The equivalent radius is iteratively solved by the critical breakdown field strength, effectively characterizing the resistance reduction characteristics of spark discharge. The iteratively solved equivalent radius is then input into the time-domain segmented circuit model, and the grounding grid impulse impedance is calculated by combining transient voltage and current data. This technical solution is highly dependent on measured soil parameters, and the existing fitting formula lacks universality. Under low soil resistivity conditions, the impact of spark effects is easily overestimated, leading to large errors in the calculated impulse impedance.
[0016] Therefore, to achieve accurate calculation of impulse impedance, this application provides a method for calculating the impulse impedance of a grounding grid, applicable to the impulse impedance detection scenario of a grounding grid under lightning current excitation. In this method, a three-dimensional simulation model of the grounding grid is obtained. This three-dimensional simulation model includes an electromagnetic field model and a circuit model. The electromagnetic field model consists of a grounding grid conductor model and a soil domain model. Then, the amplitude of the lightning current is input into the electromagnetic field model to obtain the instantaneous value of the lightning current at the target time and the global spatial potential. Next, the instantaneous value of the lightning current at the target time and the global spatial potential are input into the circuit model to obtain the target equivalent current at the target time. Then, provided that the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range, the ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current is determined as the peak impulse impedance of the grounding grid. Here, the injected node potential refers to the ground potential corresponding to the circuit node in the circuit model where the lightning current is injected.
[0017] In this embodiment, a three-dimensional simulation model including an electromagnetic field model and a circuit model is obtained. Joint calculations are then performed using both models, substituting the lightning current amplitude step-by-step to solve for the instantaneous current, space potential, and equivalent current. Then, provided the difference between the instantaneous lightning current at the target time and the target equivalent current at the target time is within a preset error range, the peak impulse impedance is obtained from the ratio of the maximum value of the injected node potential to the instantaneous peak value of the lightning current. This effectively balances the electromagnetic field distribution characteristics and circuit transmission characteristics, significantly improving the accuracy of the impulse impedance calculation. It accurately reflects the transient operating state of the grounding grid under lightning current excitation, providing accurate and reliable data for grounding grid lightning protection design, safety assessment, and operation and maintenance upgrades.
[0018] The present application will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present application can be combined with each other.
[0019] This embodiment provides a method for calculating the impulse impedance of a grounding grid, such as... Figure 1 As shown, the method includes: S101, Obtain the three-dimensional simulation model of the grounding grid.
[0020] The three-dimensional simulation model includes an electromagnetic field model and a circuit model. The electromagnetic field model consists of a grounding grid conductor model and a soil domain model.
[0021] In some embodiments, the aforementioned electromagnetic field model can be constructed based on substation design drawings and field survey data using target simulation software. The field survey data can be obtained through field measurement methods such as the four-pole method.
[0022] Specifically, based on the substation design drawings, the geometry and dimensions of the grounding grid conductors, as well as the boundary dimensions of the soil domain within the grounding grid, are determined. For example, the boundary dimensions of the soil domain could be 400 meters (m) × 500 meters × 80 meters, which is five times the dimensions of the grounding grid. Simultaneously, based on field survey data, the material parameters of the grounding grid conductors, the material parameters of the soil domain, and soil stratification information are determined. The material parameters of the grounding grid conductors include at least electrical conductivity and magnetic permeability. The material parameters of the soil domain include at least soil electrical conductivity, relative permittivity, and relative magnetic permeability. For example, the electrical conductivity of the grounding grid conductors could be 1 × 10⁻⁶. -3 Siemens per meter (S / m) has a permeability of 4π × 10⁻⁶. -7 Henry per meter (H / m). The soil electrical conductivity of the soil domain can be 1.25 × 10⁻⁶. - The relative permittivity can be 10, and the relative magnetic permeability can be 1. Soil stratification information should include at least the number of horizontal or vertical soil layers in the target area and the thickness of each layer.
[0023] In other embodiments, the circuit model described above can be obtained by discretizing the grounding grid conductor model. Specifically, the grounding grid conductor model is initially discretized using the intersection nodes as target discretization points to obtain multiple first discrete units. Then, the first discrete units with conductor lengths greater than a preset conductor length are further discretized to obtain at least two second discrete units. The conductor length of each second discrete unit is less than or equal to the preset conductor length. Next, the first discrete units with conductor lengths less than or equal to the preset conductor length, along with the at least two second discrete units, are combined to form a discrete unit set, which is used to construct a circuit model. The circuit model includes lumped parameter circuits and circuit nodes corresponding to each conductor discrete unit in the discrete unit set.
[0024] Accordingly, for each conductor discrete unit in the discrete unit set, the conductor discrete unit is equivalent to a lumped parameter circuit. This lumped parameter circuit can include resistance, inductance, conductance to ground, and capacitance to ground. When two conductor discrete units with the same endpoints exist in the discrete unit set, the sub-circuit models corresponding to the two conductor discrete units are spliced together until all target conductor discrete units are spliced together, resulting in the circuit model. Furthermore, the endpoints of each conductor discrete unit in the discrete unit set are used as circuit nodes in the circuit model.
[0025] In one implementation, the inductance in the lumped-parameter circuit described above can be calculated using the following expression: Expression 1; in, Let be the inductance of the i-th discrete conductor unit; The permeability of free space can take values of (4π × 10⁻⁶). - 7 H / m); Let be the cell length of the i-th discrete conductor cell; Let be the radius of the conductor.
[0026] In one implementation, the resistance in the lumped-parameter circuit described above can be calculated using the following expression: Expression 2; in, Let be the resistance of the i-th discrete conductor unit; The conductivity can take a value of 1×10⁻⁶. -3 S / m; Let be the cross-sectional area of the i-th discrete conductor unit.
[0027] In one implementation, the conductance to ground in the lumped parameter circuit described above can be calculated using the following expression: Expression 3; in, Let be the conductance to ground of the i-th discrete conductor unit; The soil resistivity can be taken as 1.25 × 10⁻⁶. - ³S / m; Let be the burial depth of the i-th conductor discrete unit; Let be the equivalent radius of the i-th discrete conductor unit.
[0028] In one implementation, the capacitance to ground in the lumped-parameter circuit described above can be calculated using the following expression: Expression 4; in, Let be the capacitance to ground of the i-th discrete conductor unit; is the relative permittivity of the soil domain, which can take the value 10.
[0029] Furthermore, the aforementioned electromagnetic field model can be connected to the circuit interface of the circuit model through the current field interface, thereby enabling data transmission.
[0030] S102 inputs the amplitude of the lightning current into the electromagnetic field model to obtain the instantaneous value of the lightning current and the global spatial potential at the target time.
[0031] Specifically, when injecting lightning current into a circuit node connected to the grounding grid down conductor within the circuit model, the amplitude of this lightning current can be input into the electromagnetic field model to obtain the instantaneous value of the lightning current and the global spatial potential at the target time. The target time can be the current time or any time between the injection of the lightning current and the current time.
[0032] In some cases, the aforementioned electromagnetic field model may include a lightning current excitation sub-model and a potential control sub-model. The lightning current excitation sub-model is used to output the instantaneous value of the lightning current at the target time. The potential control sub-model is used to output the global spatial potential at the target time. Simultaneously, the potential control sub-model is configured with target boundary conditions, including an infinity zero-potential boundary and a surface zero-normal current boundary. The infinity zero-potential boundary provides a reference zero point for the spatial potential of all soils within the soil domain model, and the surface zero-normal current boundary characterizes the absence of current outflow at the interface between the soil domain model and the air.
[0033] In one implementation, the magnitude of the lightning current is input into the lightning current excitation sub-model to obtain the instantaneous value of the lightning current at the target time. Specifically, the lightning current excitation sub-model can be characterized by the following expression five: Expression 5; in, Let be the instantaneous value of the lightning current at time t; The current amplitude of the lightning current can be 2000 amperes (A). It is a natural constant; This is the wave tail attenuation coefficient, which can be 2.2 × 10³ seconds. 1 (1 / s); This is the wavefront attenuation coefficient, which can be 8.5 × 10⁻⁶. 4 1 / s.
[0034] In another implementation, the three-dimensional coordinates of all spatial potentials at the target time and the medium material parameters within the aforementioned electromagnetic field model are input into the potential control sub-model to obtain the global spatial potential at the target time. Here, the medium material parameters refer to the material parameters of the grounding grid conductor model and the soil domain model within the electromagnetic field model; that is, the medium material parameters include the material parameters of the grounding grid conductor model and the soil domain model. The material parameters include conductivity and dielectric constant. Specifically, the potential control sub-model can be characterized by the following expression six: Expression 6; in, This is a potential control sub-model; Three-dimensional coordinates The space potential at that location; It is the dielectric constant (or absolute dielectric constant), which is determined based on the vacuum dielectric constant and the relative dielectric constant; It is the first-order partial derivative with respect to time t; This represents the second-order spatial distribution of space potential; For divergence operators; Electrical conductivity; Let be the potential gradient, and be the electric field intensity. Relevant quantity, that is, .
[0035] It should be noted that the above potential control sub-model is constructed based on the media constitutive equation and Maxwell's equations. The media constitutive equation describes the quantitative relationship between the electromagnetic field model and the macroscopic electromagnetic response within the media. Maxwell's equations are a set of partial differential equations describing the relationship between electric field, magnetic field, charge density, and current density.
[0036] In one implementation, the above Maxwell's equations can be characterized by the following expression seven: Expression 7; in, It is a vector differential operator; magnetic field strength curl; The conduction current density vector; The imaginary unit; Angular frequency; It is the electric displacement vector; electric field strength curl; Total current density curl, total current density Including conduction current density And displacement current density.
[0037] S103 inputs the instantaneous value of the lightning current and the global spatial potential at the target time into the circuit model to obtain the target equivalent current at the target time.
[0038] Specifically, after obtaining the instantaneous lightning current value and global spatial potential at the target time, these values can be input into the circuit model. The circuit model can include a node circuit sub-model and a current solving sub-model. The node circuit sub-model is used to calculate the initial injected node potential. The current solving sub-model is used to calculate the target equivalent current at the target time.
[0039] In some embodiments, the instantaneous value of the lightning current at the target time is input into the nodal circuit sub-model to obtain the nodal potential vector at the target time. Then, the injected node potential at the target time is extracted from the nodal potential vector at the target time. Here, the injected node potential refers to the ground potential corresponding to the circuit node in the circuit model where the lightning current is injected.
[0040] In one implementation, the above-mentioned node circuit sub-model can be characterized by the following expression: Expression 8; in, Here is the node conductance matrix; and It is a connection matrix, based on the branch incidence matrix A. （n×b） get; For the path relationship matrix; This represents the node potential vector of each circuit node in the grounding grid topology. The branch current vector; The vector of the node current source is equivalent to the instantaneous value of the lightning current at the target time mentioned above; This is the branch voltage source vector; The target equivalent current is 0 in the initial calculation.
[0041] It should be noted that the above branch correlation matrix A （n×b） This is derived from the grounding grid topology and the lumped parameter circuits corresponding to the discrete conductor units in the circuit model. Here, n is the number of circuit nodes in the grounding grid topology, and b is the number of branches in the grounding grid topology. For example, the branch correlation matrix A... （n×b） a in ij For example, element a in this association matrix ij When current flows out of circuit node i in branch j, it is recorded as 1; when current flows into circuit node i, it is recorded as -1; when branch j is not associated with circuit node i, it is recorded as 0.
[0042] Furthermore, after obtaining the injection node potential at the target time, it can be determined whether the injection node potential at the target time is the same as the global spatial potential at the target time. If the injection node potential at the target time is the same as the global spatial potential at the target time, the global spatial potential at the target time, the material parameters of the soil domain model, and the contact area between the grounding grid conductor model and the soil domain model are input into the current solving sub-model to obtain the target equivalent current at the target time. In other words, the boundary condition of the current solving sub-model is that the injection node potential at the target time is the same as the global spatial potential at the target time.
[0043] In one implementation, the above current-solving sub-model can be characterized by the following expression nine: Expression Nine; in, The target equivalent current at the target time; This represents the contact area between the grounding grid conductor model and the soil domain model. The electrical conductivity of the soil domain model; is the dielectric constant of the soil domain model; It is the first-order partial derivative with respect to the target time t; The global spatial potential at the target time; For potential gradient; electric field strength ; It is the area vector of the conductor surface pointing outwards.
[0044] S104, when the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within the preset error range, the ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current is determined as the peak impulse impedance of the grounding grid.
[0045] Specifically, after obtaining the target equivalent current at the target time, it can be determined whether the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range. The preset error range can be pre-set according to actual needs, and the specific value is not limited.
[0046] In some embodiments, if the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range, the ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current can be directly used as the peak impulse impedance of the grounding grid. The maximum value of the injected node potential and the instantaneous peak value of the lightning current are obtained after determining that the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range.
[0047] In one implementation, the peak impulse impedance of the aforementioned grounding grid can be obtained by the following expression: Expression 10; in, This represents the peak impulse impedance of the grounding grid. Let be the injection node potential at time t; This represents the maximum value of the injected node potential; Let be the instantaneous value of the lightning current at time t; This represents the instantaneous peak value of the lightning current.
[0048] In other embodiments, if the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is not within a preset error range, the injection node potential at the target time needs to be updated, and the updated injection node potential is used again as the injection node potential at the target time. Then, when the global spatial potential at the target time is the same as the injection node potential at the target time, the global spatial potential at the target time, the material parameters of the soil domain model, and the contact area between the grounding grid conductor model and the soil domain model are input into the current solving sub-model to obtain the target equivalent current at the target time. This process continues until the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range. Only then is the ratio between the maximum value of the injection node potential and the instantaneous peak value of the lightning current determined as the peak impulse impedance of the grounding grid.
[0049] In some cases, the above-mentioned process of updating the injected node potential may specifically include: adding the injected node potential at the target time and the potential perturbation to obtain the perturbed injected node potential. The potential perturbation can be preset according to actual needs, and its specific value is not limited. Then, the perturbed injected node potential, the material parameters of the soil domain model, and the contact area between the grounding grid conductor model and the soil domain model are input into the current solving sub-model to obtain the perturbed equivalent current at the target time. Finally, the Jacobian matrix is determined based on the perturbed equivalent current at the target time, the target equivalent current at the target time, and the potential perturbation.
[0050] In one implementation, the Jacobian matrix described above can be obtained by the following expression eleven: Expression 11; in, Let be the Jacobian matrix for the k-th iteration, which characterizes the partial derivative of the perturbation equivalent current with respect to the injection point voltage. ; Take potential Equivalent current of disturbance at time; This represents the injected node potential after perturbation. Let be the injected node potential at the target time of the k-th iteration. This refers to the potential disturbance. Take potential The target equivalent current at that time.
[0051] Furthermore, after obtaining the Jacobian matrix, the injection node potential at the target time can be updated based on the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time, as well as the inverse of the Jacobian matrix.
[0052] In one implementation, the process of updating the injected node potential described above can be characterized by the following expression twelve: Expression twelve; in, This is the updated (k+1)th injected node voltage; Let be the injection node potential in the k-th iteration; Jacobian matrix The inverse matrix; The instantaneous value of the lightning current at the target time; Let be the target equivalent current at the target time of the k-th iteration.
[0053] Optionally, if the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range, the injection node potential and the instantaneous value of the lightning current at each moment within a preset time period can be determined. The preset time period can be pre-set according to actual needs, and the specific value is not limited. Then, based on the injection node potential and the instantaneous value of the lightning current at each moment within the preset time period, the average impulse impedance and / or impedance time-varying curve of the grounding grid are determined.
[0054] In some cases, the injected node potentials at all times within a preset time period are integrated to obtain the cumulative injected node potentials within that time period. Furthermore, the instantaneous lightning current values at all times within the preset time period are integrated to obtain the cumulative instantaneous lightning current values within that time period. Finally, the ratio between the cumulative injected node potentials and the cumulative instantaneous lightning current values within the preset time period is determined as the average impulse impedance of the grounding grid.
[0055] In other cases, for each moment within a preset time period, the ratio between the injected node potential and the instantaneous value of the lightning current at that moment is determined as the impulse impedance of the grounding grid at that moment. Then, based on the impulse impedances corresponding to all moments within the preset time period, a time-varying impedance curve is generated.
[0056] Accordingly, after determining the injection node potential and instantaneous lightning current value at each moment within the preset time period, the field quantity distribution cloud map at that moment can also be determined based on the injection node potential and instantaneous lightning current value at each moment within the preset time period. The field quantity distribution cloud map can include a three-dimensional potential distribution cloud map and / or a current density distribution cloud map. The three-dimensional potential distribution cloud map is used to present the gradient distribution of all spatial potentials within the electromagnetic field model under the impact of lightning current. The current density distribution cloud map is used to present the evacuation path and density distribution of lightning current within the electromagnetic field model.
[0057] Furthermore, after determining the injection node potential and instantaneous lightning current value at each moment within the preset time period, sensitive parameters such as soil resistivity, conductor burial depth, and lightning current waveform parameters can also be output to assess the degree of influence of these sensitive parameters on the impulse impedance.
[0058] Furthermore, as a refinement and extension of the specific implementation of the above embodiments, and to fully illustrate the specific implementation process of this embodiment, another method for calculating the impulse impedance of the grounding grid is provided, such as... Figure 2 As shown, the method includes: S201, Obtain the three-dimensional simulation model of the grounding grid.
[0059] S202 inputs the amplitude of the lightning current into the electromagnetic field model to obtain the instantaneous value of the lightning current and the global spatial potential at the target time.
[0060] S203 inputs the instantaneous value of the lightning current at the target time into the node circuit sub-model to obtain the node potential vector at the target time.
[0061] S204, extract the injected node potential at the target time from the node potential vector at the target time.
[0062] S205, when the injection node potential at the target time is the same as the global spatial potential at the target time, the global spatial potential at the target time, the material parameters of the soil domain model, and the contact area between the grounding grid conductor model and the soil domain model are input into the current solving sub-model to obtain the target equivalent current at the target time.
[0063] S206, determine whether the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within the preset error range.
[0064] In some embodiments, if the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range, step S208 can be executed directly to determine the peak impulse impedance of the grounding grid. If the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is not within the preset error range, step S207 needs to be executed again to redetermine the target equivalent current at the target time.
[0065] S207, update the injection node potential at the target time, and use the updated injection node potential as the injection node potential at the target time again.
[0066] S208 defines the ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current as the peak impulse impedance of the grounding grid.
[0067] Furthermore, as Figure 1In terms of specific implementation, this application provides a device for calculating the impulse impedance of a grounding grid, such as... Figure 3 As shown, the device includes: a model acquisition module 301, a data output module 302, a current output module 303, and an impedance calculation module 304.
[0068] The model acquisition module 301 is used to acquire a three-dimensional simulation model of the grounding grid; wherein, the three-dimensional simulation model includes an electromagnetic field model and a circuit model, and the electromagnetic field model is composed of a grounding grid conductor model and a soil domain model; The data output module 302 is used to input the current amplitude of the lightning current into the electromagnetic field model to obtain the instantaneous value of the lightning current and the global spatial potential at the target time. The current output module 303 is used to input the instantaneous value of the lightning current and the global space potential at the target time into the circuit model to obtain the target equivalent current at the target time. Impedance calculation module 304 is used to determine the ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current as the peak impulse impedance of the grounding grid, provided that the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range; wherein, the injected node potential refers to the ground potential corresponding to the circuit node in the circuit model where the lightning current is injected.
[0069] Furthermore, in one possible implementation of this embodiment, such as Figure 3 As shown, the data output module 302 is also used to input the current amplitude of the lightning current into the lightning current excitation sub-model to obtain the instantaneous value of the lightning current at the target time. The three-dimensional coordinates of all spatial potentials at the target time and the medium material parameters in the electromagnetic field model are input into the potential control sub-model to obtain the global spatial potential at the target time.
[0070] Furthermore, in one possible implementation of this embodiment, such as Figure 3 As shown, the current output module 303 is also used to input the instantaneous value of the lightning current at the target time into the node circuit sub-model to obtain the node potential vector at the target time. Extract the injected node potential at the target time from the node potential vector at the target time; When the global spatial potential at the target time is the same as the injection node potential at the target time, the global spatial potential at the target time, the material parameters of the soil domain model, and the contact area between the grounding grid conductor model and the soil domain model are input into the current solving sub-model to obtain the target equivalent current at the target time.
[0071] Furthermore, in one possible implementation of this embodiment, such as Figure 3As shown, the impedance calculation module 304 is also used to repeatedly update the injection node potential at the target time when the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is not within the preset error range, and to use the updated injection node potential as the injection node potential at the target time again. When the global spatial potential at the target time is the same as the injection node potential at the target time, the global spatial potential at the target time, the material parameters of the soil domain model, and the contact area between the grounding grid conductor model and the soil domain model are input into the current solving sub-model to obtain the target equivalent current at the target time, until the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within the preset error range. The ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current is determined as the peak impulse impedance of the grounding grid.
[0072] Furthermore, in one possible implementation of this embodiment, such as Figure 3 As shown, the impedance calculation module 304 is also used to add the injection node potential at the target time and the potential disturbance amount to obtain the perturbed injection node potential. The perturbed injection node potential, the material parameters of the soil domain model, and the contact area between the grounding grid conductor model and the soil domain model are input into the current solving sub-model to obtain the perturbed equivalent current at the target time. The Jacobian matrix is determined based on the perturbation equivalent current at the target time, the target equivalent current at the target time, and the potential perturbation. The injection node potential at the target time is updated based on the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time, as well as the inverse of the Jacobian matrix.
[0073] Furthermore, in one possible implementation of this embodiment, such as Figure 3 As shown, the model acquisition module 301 is also used to perform initial discretization on the grounding grid conductor model with the intersection nodes of the grounding grid conductor model as the target discretization points, and obtain multiple first discrete units. The first discrete units with conductor lengths greater than a preset conductor length are discretized twice to obtain at least two second discrete units; wherein the conductor length of the second discrete unit is less than or equal to the preset conductor length. A discrete unit set is formed by combining multiple first discrete units whose conductor length is less than or equal to a preset conductor length, and at least two second discrete units. Based on the set of discrete units, a circuit model is constructed; wherein, the circuit model includes the lumped parameter circuit and circuit nodes corresponding to each conductor discrete unit in the set of discrete units.
[0074] Furthermore, in one possible implementation of this embodiment, such as Figure 3 As shown, the model acquisition module 301 is also used to convert each conductor discrete unit in the discrete unit set into an equivalent lumped parameter circuit; wherein the lumped parameter circuit includes resistance, inductance, conductance to ground and capacitance to ground; If two conductor discrete units with the same endpoint exist in the discrete unit set, the sub-circuit models corresponding to the two conductor discrete units are spliced together until all target conductor discrete units are spliced together to obtain the circuit model. The endpoints of each conductor discrete unit in the discrete unit set are used as circuit nodes in the circuit model.
[0075] Furthermore, in one possible implementation of this embodiment, such as Figure 3 As shown, the impedance calculation module 304 is also used to determine the injection node potential and instantaneous lightning current value at each moment within a preset time period. Based on the injected node potential and instantaneous lightning current value at each moment within a preset time period, determine the average impulse impedance and / or impedance time-varying curve of the grounding grid; and / or, Based on the injection node potential and instantaneous lightning current value at each moment within a preset time period, the field quantity distribution cloud map at each moment is determined; wherein, the field quantity distribution cloud map includes a three-dimensional potential distribution cloud map and / or a current density distribution cloud map. The three-dimensional potential distribution cloud map is used to present the gradient distribution of all spatial potentials in the electromagnetic field model under the impact of lightning current, and the current density distribution cloud map is used to present the evacuation path and density distribution of lightning current in the electromagnetic field model.
[0076] It should be noted that other corresponding descriptions of the functional units involved in the grounding grid impulse impedance calculation device provided in this application embodiment can be found in the following references. Figures 1 to 2 The corresponding descriptions in the method will not be repeated here.
[0077] This application also provides a computer device, specifically a personal computer, server, network device, etc. The computer device includes a bus, processor, memory, and communication interface, and may also include input / output interfaces and a display device. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database of the computer device stores location information. The network interface of the computer device is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements the steps in the various method embodiments.
[0078] Those skilled in the art will understand that the structure of the computer device described above is only a partial structure related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. A specific computer device may include more or fewer components, or combine certain components, or have different component arrangements.
[0079] In one embodiment, a computer-readable storage medium is provided, which may be non-volatile or volatile, having stored thereon a computer program that, when executed by a processor, implements the steps in the above method embodiments.
[0080] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.
[0081] It should be noted that the user personal information involved in the embodiments of this application is all authorized (with the knowledge and consent) by the relevant parties or fully authorized by all parties, and the executing entity can obtain it through various legal and compliant means. The collection, storage, use, processing, transmission, provision, and disclosure of the information, data, and signals involved all comply with the relevant laws and regulations of the relevant countries and regions, and do not violate public order and good morals. It should be noted that if any software tools or components other than those of this company appear in the embodiments of this application, they are merely illustrative examples and do not represent actual use.
[0082] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, graphics processors, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.
[0083] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0084] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.
Claims
1. A method for calculating the impulse impedance of a grounding grid, characterized in that, include: A three-dimensional simulation model of the grounding grid is obtained; wherein, the three-dimensional simulation model includes an electromagnetic field model and a circuit model, and the electromagnetic field model is composed of a grounding grid conductor model and a soil domain model; The amplitude of the lightning current is input into the electromagnetic field model to obtain the instantaneous value of the lightning current and the global spatial potential at the target time. The instantaneous value of the lightning current and the global spatial potential at the target time are input into the circuit model to obtain the target equivalent current at the target time. If the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range, the ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current is determined as the peak impulse impedance of the grounding grid; wherein, the injected node potential refers to the ground potential corresponding to the circuit node in the circuit model where the lightning current is injected.
2. The method according to claim 1, characterized in that, The electromagnetic field model includes a lightning current excitation sub-model and a potential control sub-model. The potential control sub-model is configured with target boundary conditions, which include an infinity zero potential boundary and a surface zero normal current boundary. The infinity zero potential boundary is used to provide a reference zero point for all soil spatial potentials within the soil domain model, and the surface zero normal current boundary is used to characterize that there is no current outflow at the interface between the soil domain model and the air. The step of inputting the amplitude of the lightning current into the electromagnetic field model to obtain the instantaneous value of the lightning current and the global spatial potential at the target time includes: The current amplitude of the lightning current is input into the lightning current excitation sub-model to obtain the instantaneous value of the lightning current at the target time; The three-dimensional coordinates of all spatial potentials in the electromagnetic field model at the target time, along with the medium material parameters, are input into the potential control sub-model to obtain the global spatial potential at the target time.
3. The method according to claim 1, characterized in that, The circuit model includes a node circuit sub-model and a current solving sub-model. The step of inputting the instantaneous value of the lightning current and the global spatial potential at the target time into the circuit model to obtain the target equivalent current at the target time includes: The instantaneous value of the lightning current at the target time is input into the node circuit sub-model to obtain the node potential vector at the target time; Extract the injected node potential at the target time from the node potential vector at the target time; When the global spatial potential at the target time is the same as the injection node potential at the target time, the global spatial potential at the target time, the material parameters of the soil domain model, and the contact area between the grounding grid conductor model and the soil domain model are input into the current solving sub-model to obtain the target equivalent current at the target time.
4. The method according to claim 3, characterized in that, The method further includes: If the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is not within the preset error range, the injection node potential at the target time is updated repeatedly, and the updated injection node potential is used as the injection node potential at the target time again. When the global spatial potential at the target time is the same as the injection node potential at the target time, the global spatial potential at the target time, the material parameters of the soil domain model, and the contact area between the grounding grid conductor model and the soil domain model are input into the current solving sub-model to obtain the target equivalent current at the target time, until the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within the preset error range. The ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current is determined as the peak impulse impedance of the grounding grid.
5. The method according to claim 4, characterized in that, The update of the injection node potential at the target time includes: The injected node potential at the target time and the potential perturbation amount are added together to obtain the perturbed injected node potential. The perturbed injection node potential, the material parameters of the soil domain model, and the contact area between the grounding grid conductor model and the soil domain model are input into the current solving sub-model to obtain the perturbed equivalent current at the target time. The Jacobian matrix is determined based on the perturbation equivalent current at the target time, the target equivalent current at the target time, and the potential perturbation amount. The injection node potential at the target time is updated based on the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time, as well as the inverse of the Jacobian matrix.
6. The method according to any one of claims 1-5, characterized in that, The method further includes: Using the intersection nodes of the grounding grid conductor model as the target discrete points, the grounding grid conductor model is initially discretized to obtain multiple first discrete units; The first discrete units with conductor lengths greater than a preset conductor length among the plurality of first discrete units are discretized twice to obtain at least two second discrete units; wherein the conductor length of the second discrete unit is less than or equal to the preset conductor length; The discrete unit set is composed of the first discrete units whose conductor length is less than or equal to a preset conductor length among the plurality of first discrete units, and the at least two second discrete units; Based on the set of discrete units, the circuit model is constructed; wherein, the circuit model includes the lumped parameter circuit and circuit node corresponding to each conductor discrete unit in the set of discrete units.
7. The method according to claim 6, characterized in that, The step of constructing the circuit model based on the set of discrete units includes: For each conductor discrete unit in the set of discrete units, the conductor discrete unit is equivalent to a lumped parameter circuit; wherein, the lumped parameter circuit includes resistance, inductance, conductance to ground, and capacitance to ground; If two conductor discrete units with the same endpoint exist in the set of discrete units, the sub-circuit models corresponding to the two conductor discrete units are spliced together until all target conductor discrete units are spliced together to obtain the circuit model. The endpoints of each conductor discrete unit in the discrete unit set are used as circuit nodes of the circuit model.
8. The method according to any one of claims 1-5, characterized in that, If the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range, the method further includes: Determine the injection node potential and instantaneous lightning current value at each moment within the preset time period; Based on the injected node potential and instantaneous lightning current value at each moment within the preset time period, determine the average impulse impedance and / or impedance time-varying curve of the grounding grid; and / or, Based on the injection node potential and instantaneous lightning current value at each moment within the preset time period, the field quantity distribution cloud map at that moment is determined; wherein, the field quantity distribution cloud map includes a three-dimensional potential distribution cloud map and / or a current density distribution cloud map, the three-dimensional potential distribution cloud map is used to present the gradient distribution of all spatial potentials within the electromagnetic field model under the impact of lightning current, and the current density distribution cloud map is used to present the evacuation path and density distribution of lightning current within the electromagnetic field model.
9. A device for calculating the impulse impedance of a grounding grid, characterized in that, include: The model acquisition module is used to acquire a three-dimensional simulation model of the grounding grid; wherein, the three-dimensional simulation model includes an electromagnetic field model and a circuit model, and the electromagnetic field model is composed of a grounding grid conductor model and a soil domain model; The data output module is used to input the current amplitude of the lightning current into the electromagnetic field model to obtain the instantaneous value of the lightning current and the global spatial potential at the target time. The current output module is used to input the instantaneous value of the lightning current and the global spatial potential at the target time into the circuit model to obtain the target equivalent current at the target time. The impedance calculation module is used to determine the ratio between the maximum value of the injected node potential and the instantaneous peak value of the lightning current as the peak impulse impedance of the grounding grid, provided that the difference between the instantaneous value of the lightning current at the target time and the target equivalent current at the target time is within a preset error range; wherein, the injected node potential refers to the ground potential corresponding to the circuit node in the circuit model where the lightning current is injected.
10. A computer device, comprising a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 8.