Ground wire thermal stability checking method and system based on multi-physics field coupling

Abstract

The embodiment of the invention provides a grounding wire thermal stability checking method and system based on multi-physics field coupling. According to the embodiment of the invention, the electronic equipment obtains the dynamic current sequence, obtains the pre-stored size material attributes of the grounding wire, outputs the dynamic minimum sectional area curve and the actual sectional area of the grounding wire through the electromagnetic-thermal-mechanical multi-physics field coupling simulation model, and obtains the size material attributes of the grounding wire based on the dynamic minimum sectional area curve and the actual sectional area. According to the method, the influence of the actual physical scene on the conductor is considered, so that the accuracy of the verification result can be improved.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a method and system for verifying the thermal stability of grounding wires based on multi-physics coupling. Background Technology

[0002] Grounding wires are crucial for the safe operation of power systems. Their core function is to rapidly guide fault current to ground during short-circuit faults, preventing equipment damage from overvoltage and protecting personnel safety. With the continuous expansion of power grids and the high proportion of renewable energy integration, short-circuit current levels have significantly increased, making the thermal stability of grounding wires a growing concern. Thermal stability verification aims to confirm whether the temperature rise of the grounding wire under fault current exceeds the material's tolerance limit, preventing protection failure due to overheating and melting. This is a critical aspect of power system design and operation and maintenance.

[0003] Existing grounding wire thermal stability verification techniques are mainly based on static short-circuit current models, calculating the minimum cross-sectional area through simplified formulas, and relying on human experience for parameter setting and result judgment. However, in complex power grid environments and scenarios requiring high precision, this method only considers the thermal stability coefficient and does not take into account the influence of other physical fields on the conductor, leading to deviations in the verification structure. Summary of the Invention

[0004] This invention provides a grounding wire thermal stability verification method and system based on multi-physics coupling to solve existing problems.

[0005] This invention provides a method for verifying the thermal stability of a grounding wire based on multi-physics coupling, comprising: The time-domain waveform of the short-circuit current is captured at a specific node of the substation grounding wire to generate a dynamic current sequence; Based on the dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire, the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire are output using an electromagnetic-thermal-mechanical multiphysics coupling simulation model. Based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, the thermal stability of the grounding wire is checked, and the check result is output.

[0006] Furthermore, the electromagnetic-thermal-mechanical multiphysics coupling simulation model includes an electromagnetic-thermal coupling model and a thermo-mechanical coupling model incorporating the coefficient of thermal expansion; Based on the dynamic current sequence and pre-stored dimensions and material properties of the grounding wire, the electromagnetic-thermal-mechanical multiphysics coupling simulation model is used to output the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire, including: Based on the dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire, the electromagnetic-thermal coupling model is solved using the finite element method to obtain the transient distribution of the temperature field caused by Joule heating. Based on the aforementioned dimensional material properties, the thermo-mechanical coupling model is solved using the thermo-elastic-plastic theory to obtain the conductor deformation of the grounding wire caused by temperature rise; The actual cross-sectional area of ​​the grounding wire is determined based on the conductor deformation. Based on the dynamic current sequence, the dimensional material properties, and the transient temperature field distribution, combined with the adaptive equivalent duration of the grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated.

[0007] Furthermore, the electromagnetic-thermal coupling model satisfies the following formula: ,

[0008] in, For curl operator, For electric field strength, The magnetic flux density generated by the dynamic current sequence is given by t, where t represents time, T is the temperature field, and k is the thermal conductivity. Joule heating is given, and ρ is the resistivity related to the material properties of the stated dimensions. This refers to the current density corresponding to the dynamic current sequence. c is the material density related to the material properties of the stated size, and c is the specific heat capacity related to the material properties of the stated size. The thermo-mechanical coupling model satisfies the following formula:

[0009] Where σ is stress, The elastic modulus is related to the material properties of the stated dimensions. For conductor deformation, ΔT is the temperature rise. is the coefficient of thermal expansion.

[0010] Furthermore, based on the dynamic current sequence, the dimensional material properties, and the transient temperature field distribution, combined with the adaptive equivalent duration of the grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated, including: Based on the aforementioned dimensional material properties and the aforementioned transient temperature field distribution, the thermal stability coefficient as a function of temperature is determined; Based on the dynamic current sequence and the thermal stability coefficient, and combined with the adaptive equivalent duration of grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated.

[0011] Furthermore, the process of obtaining the adaptive ground fault equivalent duration includes: Based on the operating logic of the protection devices in the substation, the equivalent duration of the ground fault is adaptively adjusted. If the operating logic of the protection device includes dual protection and circuit breaker failure protection, then the adaptive ground fault equivalent duration satisfies the following formula:

[0012] If the operating logic of the protection device includes fast-acting main protection, backup protection, and automatic reclosing, then the adaptive equivalent duration of the ground fault satisfies the following formula:

[0013] in, The adaptive ground fault equivalent duration, The duration of the primary protective action, For the failure protection action time, The circuit breaker opening time. This is the time for backup protection actions.

[0014] Furthermore, the dynamic minimum cross-sectional area curve of the grounding wire satisfies the following formula:

[0015] in, This is the dynamic minimum cross-sectional area curve of the grounding wire. It is a dynamic current sequence. The thermal stability coefficient, The adaptive equivalent duration of a ground fault is given by t, which represents time.

[0016] Furthermore, the thermal stability check of the grounding wire based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and the output of the check result, includes: If, within a continuous time range, the minimum cross-sectional area curve has a minimum cross-sectional area that is less than the actual cross-sectional area by a set proportion, then the thermal stability check of the grounding wire is determined to be unsatisfactory; otherwise, the thermal stability check of the grounding wire is determined to be satisfactory.

[0017] Furthermore, after performing thermal stability verification on the grounding wire based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and outputting the verification result, the process further includes: Dynamically display a comparison graph of the dynamic minimum cross-sectional area curve and the time-varying curve of the actual cross-sectional area; and / or This displays a three-dimensional field distribution map that overlays a cloud map of the transient temperature field distribution, a thermogram of conductor deformation, and a vector map of current density.

[0018] This invention also provides a grounding wire thermal stability verification system based on multi-physics coupling, comprising: The acquisition module is used to capture the time-domain waveform of short-circuit current at a specific node of the substation grounding wire and generate a dynamic current sequence. The simulation calculation module is used to output the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire based on the dynamic current sequence and the pre-stored size and material properties of the grounding wire, using an electromagnetic-thermal-mechanical multiphysics coupling simulation model. The verification module is used to perform thermal stability verification on the grounding wire based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and output the verification results.

[0019] Furthermore, the electromagnetic-thermal-mechanical multiphysics coupling simulation model includes an electromagnetic-thermal coupling model and a thermo-mechanical coupling model incorporating the coefficient of thermal expansion; The simulation calculation module is specifically used to solve the electromagnetic-thermal coupling model using the finite element method based on the dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire, to obtain the transient distribution of the temperature field caused by Joule heating; based on the dimensions and material properties, it uses thermo-elastic-plastic theory to solve the thermo-mechanical coupling model, to obtain the conductor deformation of the grounding wire caused by temperature rise; based on the conductor deformation, it determines the actual cross-sectional area of ​​the grounding wire; and based on the dynamic current sequence, the dimensions and material properties, and the transient distribution of the temperature field, combined with the adaptive equivalent duration of the grounding fault, it calculates the dynamic minimum cross-sectional area curve of the grounding wire.

[0020] Furthermore, the electromagnetic-thermal coupling model satisfies the following formula: ,

[0021] in, For curl operator, For electric field strength, The magnetic flux density generated by the dynamic current sequence is given by t, where t represents time, T is the temperature field, and k is the thermal conductivity. Joule heating is given, and ρ is the resistivity related to the material properties of the stated dimensions. This refers to the current density corresponding to the dynamic current sequence. c is the material density related to the material properties of the stated size, and c is the specific heat capacity related to the material properties of the stated size. The thermo-mechanical coupling model satisfies the following formula:

[0022] Where σ is stress, The elastic modulus is related to the material properties of the stated dimensions. For conductor deformation, ΔT is the temperature rise. is the coefficient of thermal expansion.

[0023] Furthermore, the simulation calculation module is specifically used to determine the thermal stability coefficient that varies with temperature based on the dimensional material properties and the transient distribution of the temperature field; and to calculate the dynamic minimum cross-sectional area curve of the grounding wire based on the dynamic current sequence and the thermal stability coefficient, combined with the adaptive equivalent duration of the grounding fault.

[0024] Furthermore, the simulation calculation module is specifically used to adaptively adjust the equivalent duration of the ground fault based on the action logic of the protection device in the substation; If the operating logic of the protection device includes dual protection and circuit breaker failure protection, then the adaptive ground fault equivalent duration satisfies the following formula:

[0025] If the operating logic of the protection device includes fast-acting main protection, backup protection, and automatic reclosing, then the adaptive equivalent duration of the ground fault satisfies the following formula:

[0026] in, The adaptive ground fault equivalent duration, The duration of the primary protective action, For the failure protection action time, The circuit breaker opening time. This is the time for backup protection actions.

[0027] Furthermore, the dynamic minimum cross-sectional area curve of the grounding wire satisfies the following formula:

[0028] in, This is the dynamic minimum cross-sectional area curve of the grounding wire. It is a dynamic current sequence. The thermal stability coefficient, The adaptive equivalent duration of a ground fault is given by t, which represents time.

[0029] Furthermore, the verification module is specifically used to determine that the thermal stability verification of the grounding wire is unsatisfactory if, within a continuous time range, the minimum cross-sectional area of ​​the dynamic minimum cross-sectional area curve has a set proportion that is smaller than the actual cross-sectional area; otherwise, it determines that the thermal stability verification of the grounding wire is satisfactory.

[0030] Furthermore, the verification module is also used to dynamically display a comparison diagram of the dynamic minimum cross-sectional area curve and the time-varying curve of the actual cross-sectional area; and / or to display a three-dimensional field distribution diagram superimposed with a cloud map of the transient distribution of the temperature field, a thermogram of the conductor deformation, and a vector map of the current density.

[0031] This application also provides an electronic device, which includes at least a processor and a memory, wherein the processor is used to execute a computer program stored in the memory to implement the steps of the grounding wire thermal stability verification method based on multiphysics coupling as described above.

[0032] In this embodiment, the electronic device acquires a dynamic current sequence and pre-stores the size and material properties of the grounding wire. It then uses an electromagnetic-thermal-mechanical multiphysics coupling simulation model to output the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire. Based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, the grounding wire is thermally stabilized and the verification result is output. Since this method takes into account the influence of the actual physical scene on the conductor, the accuracy of the verification result can be improved. Attached Figure Description

[0033] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A flowchart illustrating a grounding wire thermal stability verification method based on multi-physics coupling provided in an embodiment of the present invention; Figure 2 A schematic diagram showing the verification results provided in an embodiment of this application; Figure 3 A schematic diagram of a verification result report display interface provided in an embodiment of this application; Figure 4 A schematic diagram of a verification result report display interface provided in an embodiment of this application; Figure 5 A schematic diagram of a verification result report display interface provided in an embodiment of this application; Figure 6 A detailed schematic diagram of a grounding wire thermal stability verification method based on dynamic short-circuit current and multi-physics field coupling provided for embodiments of this application; Figure 7 This is a schematic diagram of a grounding wire thermal stability verification system based on multi-physics coupling, provided in an embodiment of the present invention. Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0035] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this invention is for describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0036] Example 1: Figure 1 This is a flowchart illustrating a grounding wire thermal stability verification method based on multi-physics coupling, provided by an embodiment of the present invention. The process includes the following steps: S101: Capture the time-domain waveform of short-circuit current at a specific node of the substation grounding wire to generate a dynamic current sequence.

[0037] The grounding wire thermal stability verification method based on multi-physics coupling provided in this application embodiment is applied to electronic devices, such as PCs or servers.

[0038] To perform thermal stability verification of the grounding wire, in this embodiment of the application, a current sensing device can be deployed at a specific node of the substation grounding wire to capture the current time-domain waveform when a short-circuit fault occurs in real time and construct a dynamic current sequence. In one possible implementation, the specific node can be located at the connection point of the neutral point grounding lead of the main transformer, the intersection of the grounding grid and the grounding lead-in line, etc.

[0039] The obtained dynamic sequence not only includes the amplitude, phase, attenuated DC component and transient impact characteristics of the short-circuit current, but also reflects the non-periodic response process of the system in the early stage of the fault, such as the rapid rise of current caused by the low inertia characteristics of new energy units, resonance overshoot, and the current superposition effect under multiple power supply grid connection.

[0040] In this embodiment, the following steps can be performed by the dynamic short-circuit current acquisition module of the electronic device: (1) Real-time sensor network: Deploy high-precision Hall current sensors (sampling frequency ≥ 10kHz) at key nodes of the substation grounding wire to capture the time-domain waveform of the short-circuit current in real time and generate a dynamic current sequence Ig(t). (2) Historical database integration: Combine historical fault data of the power grid (such as fault type, current amplitude, and duration) to build a dynamic current feature library to support current prediction models based on machine learning. (3) Data preprocessing unit: Perform noise reduction and normalization on the original current signal and extract effective current features (such as peak value, rising slope, and duration).

[0041] S102: Based on the dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire, the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire are output using the electromagnetic-thermal-mechanical multiphysics coupling simulation model.

[0042] In this embodiment, an electromagnetic-thermal-mechanical multiphysics coupling simulation model is pre-stored. The electronic device can acquire the pre-stored dimensions and material properties of the grounding wire. The material properties may include at least one parameter among electrical conductivity, thermal conductivity, specific heat capacity, density, temperature coefficient of resistance, and mechanical strength parameters. The electronic device can process the collected dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire using the electromagnetic-thermal-mechanical multiphysics coupling simulation model. In one possible implementation, the electromagnetic-thermal-mechanical multiphysics coupling simulation model can output the dynamic minimum cross-sectional curve and the actual cross-section of the grounding wire.

[0043] S103: Based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, perform thermal stability verification on the grounding wire and output the verification result.

[0044] Electronic devices can perform thermal stability verification analysis based on the generated dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire. In one possible implementation, the verification process can compare the actual cross-sectional area with the minimum cross-sectional area required at each time point in a time-step manner: if the actual cross-sectional area is greater than or equal to the dynamic minimum cross-sectional area at any time, the period is determined to be in a thermally safe state; if the actual cross-sectional area is less than the dynamic minimum cross-sectional area, it is marked as a thermally unstable period. In one possible implementation, if the duration of the thermally unstable period exceeds a preset duration, the verification result can be determined to be unsatisfactory.

[0045] This application provides a grounding wire thermal stability verification system and method based on dynamic short-circuit current and multi-physics field coupling.

[0046] In this embodiment, the electronic device acquires a dynamic current sequence and pre-stores the size and material properties of the grounding wire. It then uses an electromagnetic-thermal-mechanical multiphysics coupling simulation model to output the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire. Based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, the grounding wire is thermally stabilized and the verification result is output. Since this method takes into account the influence of the actual physical scene on the conductor, the accuracy of the verification result can be improved.

[0047] Example 2: The electromagnetic-thermal-mechanical multiphysics coupling simulation model includes an electromagnetic-thermal coupling model and a thermo-mechanical coupling model incorporating the coefficient of thermal expansion. Based on the dynamic current sequence and pre-stored dimensions and material properties of the grounding wire, the electromagnetic-thermal-mechanical multiphysics coupling simulation model is used to output the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire, including: Based on the dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire, the electromagnetic-thermal coupling model is solved using the finite element method to obtain the transient distribution of the temperature field caused by Joule heating. Based on the aforementioned dimensional material properties, the thermo-mechanical coupling model is solved using the thermo-elastic-plastic theory to obtain the conductor deformation of the grounding wire caused by temperature rise; The actual cross-sectional area of ​​the grounding wire is determined based on the conductor deformation. Based on the dynamic current sequence, the dimensional material properties, and the transient temperature field distribution, combined with the adaptive equivalent duration of the grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated.

[0048] The electromagnetic-thermal-mechanical multiphysics coupling simulation model in the embodiments of this application includes an electromagnetic-thermal coupling model and a thermo-mechanical coupling model that incorporates the coefficient of thermal expansion.

[0049] In one possible implementation, the electronic device can first use the finite element method to solve the electromagnetic-thermal coupling model. For example, in the electromagnetic field module, the low-frequency approximation form of Maxwell's equations (i.e., the quasi-static electromagnetic field equations) is solved to accurately calculate the distribution characteristics of the short-circuit current on the conductor cross-section, fully considering the skin effect, proximity effect, and the nonlinear effects of the material conductivity with temperature change. Based on the current density distribution, the internal heat source generated by Joule heating is calculated step by step and input as a heat source term into the transient heat conduction equation. Combining the comprehensive heat dissipation boundary conditions such as convection, radiation, and conduction, the three-dimensional transient temperature field is solved to obtain the spatial-temporal temperature distribution cloud map of the grounding wire from the initial temperature to the peak temperature rise, identify the hot spot formation location and the heat accumulation evolution path, and obtain the transient temperature field distribution caused by Joule heating.

[0050] Based on the dimensional and material properties, the thermo-mechanical coupling model is solved using thermo-elastic-plastic theory to obtain the conductor deformation of the grounding wire caused by temperature rise. For example, the temperature field is applied as a volume load to the structural mechanics model to calculate the thermal stress and strain caused by uneven heating. Considering the decrease in yield strength, creep behavior, and local plastic deformation capacity of the material at high temperatures, an incremental iterative method is used to solve the nonlinear constitutive relation, simulating deformation phenomena such as bending, warping, joint loosening, and even local necking of the conductor under repeated or continuous thermal shock. Specifically, the risk of residual stress concentration due to limited thermal expansion is assessed in structurally weak areas such as connection terminals, bending sections, and transition joints. This determines the conductor deformation of the grounding wire caused by temperature rise.

[0051] Based on the conductor deformation results obtained from simulation, the effective conductive path and actual usable cross-sectional area are reconstructed in reverse: the cross-sectional profile of the conductor after plastic deformation is extracted by geometric reconstruction technology, the oxide layer, corrosion area and microcrack influence area are deducted, and the actual cross-sectional area after dynamic degradation is calculated.

[0052] Electronic devices can calculate the dynamic minimum cross-sectional area curve of a grounding wire based on a dynamic current sequence, the size and material properties of the grounding wire, and the adaptive distribution of the temperature field, resulting in an equivalent duration of a ground fault. For example, an identification model can be pre-saved, and the dynamic current sequence, the size and material properties of the grounding wire, the adaptive distribution of the temperature field, and the resulting equivalent duration of a ground fault can be input into this identification model to obtain the dynamic minimum cross-sectional area curve of the grounding wire output by the identification model.

[0053] Example 3: Based on the above embodiments, in this embodiment of the application, the electromagnetic-thermal coupling model satisfies the following formula: ,

[0054] in, For curl operator, For electric field strength, The magnetic flux density generated by the dynamic current sequence is given by t, where t represents time, T is the temperature field, and k is the thermal conductivity. Joule heating is given, and ρ is the resistivity related to the material properties of the stated dimensions. This refers to the current density corresponding to the dynamic current sequence. c is the material density related to the material properties of the stated size, and c is the specific heat capacity related to the material properties of the stated size. This represents the transient distribution of the temperature field caused by Joule heating; The thermo-mechanical coupling model satisfies the following formula:

[0055] Where σ is stress, The elastic modulus is related to the material properties of the stated dimensions. For conductor deformation, ΔT is the temperature rise. is the coefficient of thermal expansion.

[0056] In this embodiment of the application, the electronic device can first calculate the rotation operator using the following formula:

[0057] in, For curl operator, For electric field strength, Let be the magnetic flux density generated by the dynamic current sequence, and t represent time. This formula describes the process by which a time-varying magnetic field induces an electric field inside a conductor and is fundamental for calculating eddy current distribution and energy loss.

[0058] After determining the rotation operator, the electronic device can use the finite element method to calculate the transient distribution of the temperature field caused by Joule heating using the following formula:

[0059] in, Here, curl operator is used, and k is the thermal conductivity. Joule heating, where ρ is the resistivity, which is related to the size and material properties. This represents the current density corresponding to the dynamic current sequence. Here, c represents the material density, which is a dimensionally related material property, and c represents the specific heat capacity, which is also a dimensionally related material property. This represents the transient distribution of the temperature field caused by Joule heating, and this represents the rate of change of temperature with respect to time.

[0060] The conductor deformation of the grounding wire due to temperature rise can be determined using the thermo-elastic-plastic theory, as follows:

[0061] Where σ is stress, The elastic modulus is a property of the material related to its dimensions. For conductor deformation, ΔT is the temperature rise. is the coefficient of thermal expansion.

[0062] Example 4: Based on the above embodiments, in this embodiment, the dynamic minimum cross-sectional area curve of the grounding wire is calculated based on the dynamic current sequence, the dimensional material properties, and the transient temperature field distribution, combined with the adaptive equivalent duration of the grounding fault, including: Based on the aforementioned dimensional material properties and the aforementioned transient temperature field distribution, the thermal stability coefficient as a function of temperature is determined; Based on the dynamic current sequence and the thermal stability coefficient, and combined with the adaptive equivalent duration of grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated.

[0063] To calculate the dynamic minimum cross-sectional area curve of the grounding wire, a temperature-dependent thermodynamic analysis method can be introduced based on the dimensions and material properties of the grounding wire and the obtained transient temperature field distribution. This method dynamically solves for the thermal stability coefficient that evolves with temperature rise. For example, the thermal stability coefficient is essentially a comprehensive parameter reflecting the material's ability to withstand short-term high-current thermal effects per unit cross-sectional area. Its theoretical expression comes from the thermal equilibrium integral model.

[0064] Where T0 is the initial operating temperature (usually 40°C), Tmax is the maximum allowable transient temperature of the material (e.g., 300°C for copper, 400°C for galvanized steel), c(T) and ρ(T) are the functions of specific heat capacity and resistivity with respect to temperature, respectively, both obtained from the material database and calculated by interpolation, T is time, and k(T) is the thermal stability coefficient that varies with temperature. By using numerical integration and combining the actual temperature rise path experienced by the conductor during the fault process, a dynamic curve of temperature evolution is determined, which more accurately characterizes the material's true tolerance under non-uniform heating conditions.

[0065] Considering that the fault duration in a grounding system is not fixed in actual operation, it is affected by factors such as relay protection operation logic, circuit breaker breaking characteristics, reclosing strategies, and the low inertia response of new energy units. Therefore, an adaptive grounding fault equivalent duration model is introduced, which calculates the effective thermal action time based on the collected dynamic current sequence and the energy equivalence principle.

[0066] Based on this, a dynamic minimum cross-sectional area calculation model can be developed:

[0067] Where Amin(t) is the minimum cross-sectional area at time t, k(T(t)) is the value stored for T(t), T(t) is the temperature at time t, teq is the effective thermal action time, and I(τ) is the dynamic current sequence.

[0068] Example 5: Based on the above embodiments, in this embodiment of the application, the process of obtaining the adaptive ground fault equivalent duration includes: Based on the operating logic of the protection devices in the substation, the equivalent duration of the ground fault is adaptively adjusted. If the operating logic of the protection device includes dual protection and circuit breaker failure protection, then the adaptive ground fault equivalent duration satisfies the following formula:

[0069] If the operating logic of the protection device includes fast-acting main protection, backup protection, and automatic reclosing, then the adaptive equivalent duration of the ground fault satisfies the following formula:

[0070] in, The adaptive ground fault equivalent duration, The duration of the primary protective action, For the failure protection action time, The circuit breaker opening time. This is the time for backup protection actions.

[0071] In the embodiments of this application, the equivalent duration is different when the operating logic of the protection device in the substation is different. Based on this, the equivalent duration of the ground fault can be adaptively adjusted according to the operating logic of the protection device in the substation.

[0072] If the operating logic of the protection device includes dual protection and circuit breaker failure protection, then the adaptive ground fault equivalent duration satisfies the following formula:

[0073] in, For adaptive ground fault equivalent duration, The duration of the primary protective action, For the failure protection action time, This refers to the circuit breaker's opening time.

[0074] If the operating logic of the protection device includes fast-acting main protection, backup protection, and automatic reclosing, then the adaptive equivalent duration of the ground fault satisfies the following formula:

[0075] in, For adaptive ground fault equivalent duration, The duration of the primary protective action, For the failure protection action time, The circuit breaker opening time. This is the time for backup protection actions.

[0076] Example 6: Based on the above embodiments, in this embodiment, the dynamic minimum cross-sectional area curve of the grounding wire satisfies the following formula:

[0077] in, This is the dynamic minimum cross-sectional area curve of the grounding wire. It is a dynamic current sequence. The thermal stability coefficient, The adaptive equivalent duration of a ground fault is given by t, which represents time.

[0078] The dynamic minimum cross-sectional area curve can be determined using the following formula:

[0079] in, This is the dynamic minimum cross-sectional area curve of the grounding wire. It is a dynamic current sequence. The thermal stability coefficient is defined as follows: in one possible implementation, different values ​​of T(t) correspond to different stored thermal stability coefficients. T(t) represents the real-time temperature of the grounding conductor at time t, i.e., the instantaneous temperature rise caused by Joule heating due to the short-circuit current. The adaptive equivalent duration of a ground fault is given by t, which represents time.

[0080] in, Here is the thermal stability coefficient of the grounding wire material. Steel: Thermal stability coefficient C = 70, maximum allowable temperature 400℃. Aluminum: Thermal stability coefficient C = 120, maximum allowable temperature 300℃. Copper: Thermal stability coefficient C = 210, maximum allowable temperature 450℃.

[0081] In one possible implementation, a functional relationship between material properties and temperature can be established based on a material degradation model, such as the resistivity of copper ρ(T) = ρ0[1 + α(T)]. [T0)], where ρ0 is the preset resistivity, α is the preset coefficient, T is the current temperature, T0 is the preset initial temperature, and the thermal stability coefficient C(T) is corrected in real time.

[0082] Example 7: Based on the above embodiments, in this embodiment, the grounding wire is thermally stabilized based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and the verification result is output, including: If, within a continuous time range, the minimum cross-sectional area curve has a minimum cross-sectional area that is less than the actual cross-sectional area by a set proportion, then the thermal stability check of the grounding wire is determined to be unsatisfactory; otherwise, the thermal stability check of the grounding wire is determined to be satisfactory.

[0083] In this embodiment of the application, the electronic device can determine whether the minimum cross-sectional area of ​​the dynamic minimum cross-sectional area curve at a set ratio is less than the actual cross-sectional area within a continuous time range. The continuous time range can be 10ms, and the set ratio can be 75%. If it is determined that the minimum cross-sectional area of ​​the dynamic minimum cross-sectional area curve at the set ratio is less than the actual cross-sectional area within the continuous time range, the thermal stability check of the grounding wire can be determined to be unsatisfactory. If it is determined that the minimum cross-sectional area of ​​the dynamic minimum cross-sectional area curve at the set ratio is not less than the actual cross-sectional area within the continuous time range, the thermal stability check of the grounding wire can be determined to be unsatisfactory.

[0084] Furthermore, the verification results can be divided into multiple evaluation levels, each with corresponding visual prompts and operational suggestions: 1) Satisfied Status: Highlighted in green, indicating that the current grounding wire material, cross-sectional area, and protection configuration meet thermal stability requirements. The system recommends maintaining the existing design parameters and allows users to mark "Accepted" with a safety margin value on the interface.

[0085] 2) Unsatisfactory Status: Marked with a red warning, indicating an overheating risk that may lead to insulation damage or mechanical failure. The system automatically pushes optimization suggestions, such as replacing with higher heat-resistant materials (e.g., replacing copper with steel-core composite materials), increasing the conductor cross-sectional area, or shortening the relay protection action time to reduce the Joule integral (I²t) energy input.

[0086] 3) Incomplete Parameter Status: Indicated by a yellow warning, indicating missing input data (e.g., material specific heat capacity, temperature coefficient of resistance, or environmental heat dissipation conditions are not provided). The system automatically loads preset default parameters to complete the estimation and marks the results as "Based on default value" and the confidence level (e.g., low / medium / high), reminding the user to verify the integrity of the original data.

[0087] 4) Interactive Optimization Mode: This mode allows users to directly drag and drop key parameters (such as protection action time or initial temperature) through a graphical interface, updating the dynamic minimum cross-sectional area curve in real time and providing feedback on the latest verification results and level changes, forming a closed-loop human-machine collaborative design process. This function is particularly suitable for multi-solution comparison and emergency modification scenarios.

[0088] Figure 2 This is a schematic diagram showing the verification results provided in an embodiment of this application.

[0089] like Figure 2 As shown, the verification results may be unsatisfactory or incomplete in terms of parameters, and the corresponding display includes equipment name, voltage level, grounding side, maximum grounding current, equivalent duration, thermal stability coefficient, minimum cross-sectional area, grounding electrode cross-sectional area, and actual cross-sectional area.

[0090] Figures 3-5 This is a schematic diagram of a verification result report display interface provided in an embodiment of this application.

[0091] Figure 3 To ensure the verification results meet the requirements of the corresponding display interface, Figure 4 If the verification result does not meet the corresponding display interface, Figure 5 This is the display interface for cases where the verification result indicates insufficient parameters.

[0092] Based on the above embodiments, in this embodiment, after performing thermal stability verification on the grounding wire based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and outputting the verification result, the following is also included: Dynamically display a comparison graph of the dynamic minimum cross-sectional area curve and the time-varying curve of the actual cross-sectional area; and / or This displays a three-dimensional field distribution map that overlays a cloud map of the transient temperature field distribution, a thermogram of conductor deformation, and a vector map of current density.

[0093] After verifying the thermal stability of the grounding wire based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area and outputting the verification results, the following visualization processing steps can also be included: The system dynamically generates and displays a comparison graph of the dynamic minimum cross-sectional area curve and the actual cross-sectional area curve over time. In one possible implementation, the curve comparison graph can be plotted with time on the horizontal axis and the effective cross-sectional area of ​​the conductor on the vertical axis, reflecting in real time the evolution of the safety margin of the grounding wire under short-circuit current, overload conditions, or transient thermal shock. When the actual cross-sectional area is lower than the dynamic minimum cross-sectional area threshold, a high-brightness warning mark is made on the curve comparison graph to indicate the risk range of thermal stability failure.

[0094] It can also generate and display a three-dimensional visualization field distribution map of multi-physics coupling. The three-dimensional field distribution map is superimposed and presented in the same spatiotemporal coordinate: transient distribution cloud map of temperature field, used to characterize the temperature rise gradient and hot spot location in each region of the grounding wire; thermogram of conductor deformation caused by thermal expansion, reflecting the area of ​​mechanical stress concentration and structural deformation trend; vector map of current density, showing the current path distribution, skin effect characteristics and local current congestion area.

[0095] In addition, the verification results and visualization graphics can be integrated into the monitoring platform interface, supporting the automatic generation of diagnostic reports, historical trend comparisons and early warning pushes, thereby improving the operational safety and intelligent operation and maintenance level of the grounding system.

[0096] Existing grounding wire thermal stability verification techniques are mainly based on static short-circuit current models, calculating the minimum cross-sectional area through simplified formulas, and relying on manual experience for parameter setting and result judgment. However, this method has the following drawbacks in complex power grid environments and scenarios requiring high precision: (1) Insufficient static current assumption: The actual short-circuit current has dynamic time-varying characteristics. The static model cannot reflect the dynamic coupling effect of current amplitude and time, resulting in deviation of the verification results.

[0097] (2) Limitations of single-field analysis: Traditional methods only consider the thermal stability coefficient and ignore the influence of the coupling of multiple physical fields such as electromagnetic field and mechanical stress field on the thermal expansion of conductor and material deformation, thus limiting the verification accuracy.

[0098] (3) Parameters depend on empirical values: key parameters such as diversion coefficient and equivalent duration rely on empirical formulas or simplified calculations, lack real-time data support, and the error accumulation is significant.

[0099] (4) Low level of intelligence: The verification results are displayed in a single form, lacking dynamic visualization and adaptive optimization suggestions, which makes it difficult to meet the needs of complex power grid scenarios.

[0100] This application proposes a ground fault modeling method based on real-time dynamic short-circuit current sensing. It constructs a time-varying current sequence using high-frequency sensing, overcoming the limitations of static models. An electromagnetic-thermal-mechanical multiphysics coupled simulation framework is established, and the accurate simulation of the grounding wire's thermal behavior is achieved by solving the coupled field equations. An adaptive dynamic verification algorithm for protection logic is designed, and an intelligent evaluation system is constructed, realizing a paradigm shift from experience-based judgment to precise evaluation. This application has the following advantages: (1) High-precision dynamic modeling: By deploying high-frequency Hall sensors (sampling rate ≥ 10kHz) and real-time data preprocessing algorithms, the time-domain characteristics of short-circuit current are accurately captured, including asymmetric components, DC attenuation and high-frequency harmonics. This breaks through the limitation of the "average value assumption" of traditional static models and significantly improves the verification accuracy.

[0101] (2) Multi-physics field coupling analysis: By combining thermal, electromagnetic and mechanical field effects, the stability of conductors under complex working conditions can be comprehensively evaluated.

[0102] (3) Adaptive parameter optimization: Based on the action signal of the protection device (such as the circuit breaker tripping status, failure protection triggering), the equivalent time is dynamically adjusted in real time, reducing the reliance on experience and avoiding the "time drift" error of the traditional fixed formula.

[0103] (4) Intelligent interactive interface: 3D visualization and real-time feedback function to support rapid decision-making and solution iteration.

[0104] Figure 6 A detailed schematic diagram of a grounding wire thermal stability verification method based on dynamic short-circuit current and multi-physics field coupling provided for embodiments of this application is shown below: Step 1: Hardware Deployment and Data Acquisition 1. Sensor installation: Install a Hall current sensor (model HT-S100) at the key node of the grounding wire to ensure sampling accuracy of ±0.5%.

[0105] 2. Communication network configuration: Transmit sensor data to the edge computing gateway in real time via fiber optic or 5G network.

[0106] 3. Cloud database setup: Use a structured query language database system (MySQL) to store historical fault data, and deploy the Apache (Spark) engine for data cleaning and feature extraction.

[0107] Step 2: Multiphysics Simulation Modeling 1. Model parameter input: (1) Input the conductor geometric dimensions and material properties (e.g., for copper, C = 210, elastic modulus E = 110 GPa).

[0108] (2) Set the boundary conditions (ambient temperature, heat transfer coefficient).

[0109] 2. Coupled solver configuration: (1) Establish an electromagnetic-thermal-mechanical multi-physics coupled project in ANSYS Workbench and set the parallel computing nodes (≥8 cores).

[0110] (2) Define the time step Δt ≤ 1 ms to ensure the accuracy of transient simulation.

[0111] Step 3: Check calculation and optimization 1. Dynamic current loading: Import the real-time collected Ig(t) into the simulation model and start the transient calculation.

[0112] 2. Adaptive equivalent time correction: (1) If the main protection action signal is detected, automatically switch to te = tm + tf + to; (2) If the current decays below 10% of the peak value, terminate the integral calculation.

[0113] 3. Generation of check results: (1) Output the dynamic minimum cross-sectional area curve Sgcal(t) and the actual cross-sectional area Sgrel; (2) Trigger the warning logic: If 75%Sgcal(t) < Sgrel lasts for more than (10, ms), mark it as "not satisfied".

[0114] Step 4: Report generation and interaction optimization 1. Intelligent report generation: Automatically generate a PDF report containing key data tables, field distribution diagrams, and optimization suggestions.

[0115] 2. User interaction adjustment: (1) In the visualization interface, the user can drag the time axis to observe the check status at different times; (2) Modify the protection time te or material parameters, and the system will update the check results in real time.

[0116] Example 8: Based on the same concept, Figure 7 A structural schematic diagram of a grounding wire thermal stability check system based on multi-physics coupling provided by an embodiment of this application includes: An acquisition module, configured to capture the time-domain waveform of the short-circuit current at specific nodes of the substation grounding wire and generate a dynamic current sequence; The simulation calculation module is used to output the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire based on the dynamic current sequence and the pre-stored size and material properties of the grounding wire, using an electromagnetic-thermal-mechanical multiphysics coupling simulation model. The verification module is used to perform thermal stability verification on the grounding wire based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and output the verification results.

[0117] Furthermore, the electromagnetic-thermal-mechanical multiphysics coupling simulation model includes an electromagnetic-thermal coupling model and a thermo-mechanical coupling model incorporating the coefficient of thermal expansion; The simulation calculation module is specifically used to solve the electromagnetic-thermal coupling model using the finite element method based on the dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire, to obtain the transient distribution of the temperature field caused by Joule heating; based on the dimensions and material properties, it uses thermo-elastic-plastic theory to solve the thermo-mechanical coupling model, to obtain the conductor deformation of the grounding wire caused by temperature rise; based on the conductor deformation, it determines the actual cross-sectional area of ​​the grounding wire; and based on the dynamic current sequence, the dimensions and material properties, and the transient distribution of the temperature field, combined with the adaptive equivalent duration of the grounding fault, it calculates the dynamic minimum cross-sectional area curve of the grounding wire.

[0118] Furthermore, the electromagnetic-thermal coupling model satisfies the following formula: ,

[0119] in, For curl operator, For electric field strength, The magnetic flux density generated by the dynamic current sequence is given by t, where t represents time, T is the temperature field, and k is the thermal conductivity. Joule heating is given, and ρ is the resistivity related to the material properties of the stated dimensions. This refers to the current density corresponding to the dynamic current sequence. c is the material density related to the material properties of the stated size, and c is the specific heat capacity related to the material properties of the stated size. The thermo-mechanical coupling model satisfies the following formula:

[0120] Where σ is stress, The elastic modulus is related to the material properties of the stated dimensions. For conductor deformation, ΔT is the temperature rise. is the coefficient of thermal expansion.

[0121] Furthermore, the simulation calculation module is specifically used to determine the thermal stability coefficient that varies with temperature based on the dimensional material properties and the transient distribution of the temperature field; and to calculate the dynamic minimum cross-sectional area curve of the grounding wire based on the dynamic current sequence and the thermal stability coefficient, combined with the adaptive equivalent duration of the grounding fault.

[0122] Furthermore, the simulation calculation module is specifically used to adaptively adjust the equivalent duration of the ground fault based on the action logic of the protection device in the substation; If the operating logic of the protection device includes dual protection and circuit breaker failure protection, then the adaptive ground fault equivalent duration satisfies the following formula:

[0123] If the operating logic of the protection device includes fast-acting main protection, backup protection, and automatic reclosing, then the adaptive equivalent duration of the ground fault satisfies the following formula:

[0124] in, The adaptive ground fault equivalent duration, The duration of the primary protective action, For the failure protection action time, The circuit breaker opening time. This is the time for backup protection actions.

[0125] Furthermore, the dynamic minimum cross-sectional area curve of the grounding wire satisfies the following formula:

[0126] in, This is the dynamic minimum cross-sectional area curve of the grounding wire. It is a dynamic current sequence. The thermal stability coefficient, The adaptive equivalent duration of a ground fault is given by t, which represents time.

[0127] Furthermore, the verification module is specifically used to determine that the thermal stability verification of the grounding wire is unsatisfactory if, within a continuous time range, the minimum cross-sectional area of ​​the dynamic minimum cross-sectional area curve has a set proportion that is smaller than the actual cross-sectional area; otherwise, it determines that the thermal stability verification of the grounding wire is satisfactory.

[0128] Furthermore, the verification module is also used to dynamically display a comparison diagram of the dynamic minimum cross-sectional area curve and the time-varying curve of the actual cross-sectional area; and / or to display a three-dimensional field distribution diagram superimposed with a cloud map of the transient distribution of the temperature field, a thermogram of the conductor deformation, and a vector map of the current density.

[0129] Example 9: Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Based on the above embodiments, this application also provides an electronic device, including a processor 801, a communication interface 802, a memory 803, and a communication bus 804, wherein the processor 801, the communication interface 802, and the memory 803 communicate with each other through the communication bus 804. The memory 803 stores a computer program. When the program is executed by the processor 801, the processor 801 performs the following steps: The time-domain waveform of the short-circuit current is captured at a specific node of the substation grounding wire to generate a dynamic current sequence; Based on the dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire, the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire are output using an electromagnetic-thermal-mechanical multiphysics coupling simulation model. Based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, the thermal stability of the grounding wire is checked, and the check result is output.

[0130] Furthermore, the electromagnetic-thermal-mechanical multiphysics coupling simulation model includes an electromagnetic-thermal coupling model and a thermo-mechanical coupling model incorporating the coefficient of thermal expansion; Based on the dynamic current sequence and pre-stored dimensions and material properties of the grounding wire, the electromagnetic-thermal-mechanical multiphysics coupling simulation model is used to output the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire, including: Based on the dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire, the electromagnetic-thermal coupling model is solved using the finite element method to obtain the transient distribution of the temperature field caused by Joule heating. Based on the aforementioned dimensional material properties, the thermo-mechanical coupling model is solved using the thermo-elastic-plastic theory to obtain the conductor deformation of the grounding wire caused by temperature rise; The actual cross-sectional area of ​​the grounding wire is determined based on the conductor deformation. Based on the dynamic current sequence, the dimensional material properties, and the transient temperature field distribution, combined with the adaptive equivalent duration of the grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated.

[0131] Furthermore, the electromagnetic-thermal coupling model satisfies the following formula: ,

[0132] in, For curl operator, For electric field strength, The magnetic flux density generated by the dynamic current sequence is given by t, where t represents time, T is the temperature field, and k is the thermal conductivity. Joule heating is given, and ρ is the resistivity related to the material properties of the stated dimensions. This refers to the current density corresponding to the dynamic current sequence. c is the material density related to the material properties of the stated size, and c is the specific heat capacity related to the material properties of the stated size. The thermo-mechanical coupling model satisfies the following formula:

[0133] Where σ is stress, The elastic modulus is related to the material properties of the stated dimensions. For conductor deformation, ΔT is the temperature rise. is the coefficient of thermal expansion.

[0134] Furthermore, based on the dynamic current sequence, the dimensional material properties, and the transient temperature field distribution, combined with the adaptive equivalent duration of the grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated, including: Based on the aforementioned dimensional material properties and the aforementioned transient temperature field distribution, the thermal stability coefficient as a function of temperature is determined; Based on the dynamic current sequence and the thermal stability coefficient, and combined with the adaptive equivalent duration of grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated.

[0135] Furthermore, the process of obtaining the adaptive ground fault equivalent duration includes: Based on the operating logic of the protection devices in the substation, the equivalent duration of the ground fault is adaptively adjusted. If the operating logic of the protection device includes dual protection and circuit breaker failure protection, then the adaptive ground fault equivalent duration satisfies the following formula:

[0136] If the operating logic of the protection device includes fast-acting main protection, backup protection, and automatic reclosing, then the adaptive equivalent duration of the ground fault satisfies the following formula:

[0137] in, The adaptive ground fault equivalent duration, The duration of the primary protective action, For the failure protection action time, The circuit breaker opening time. This is the time for backup protection actions.

[0138] Furthermore, the dynamic minimum cross-sectional area curve of the grounding wire satisfies the following formula:

[0139] in, This is the dynamic minimum cross-sectional area curve of the grounding wire. It is a dynamic current sequence. The thermal stability coefficient, The adaptive equivalent duration of a ground fault is given by t, which represents time.

[0140] Furthermore, the thermal stability check of the grounding wire based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and the output of the check result, includes: If, within a continuous time range, the minimum cross-sectional area curve has a minimum cross-sectional area that is less than the actual cross-sectional area by a set proportion, then the thermal stability check of the grounding wire is determined to be unsatisfactory; otherwise, the thermal stability check of the grounding wire is determined to be satisfactory.

[0141] Furthermore, after performing thermal stability verification on the grounding wire based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and outputting the verification result, the process further includes: Dynamically display a comparison graph of the dynamic minimum cross-sectional area curve and the time-varying curve of the actual cross-sectional area; and / or This displays a three-dimensional field distribution map that overlays a cloud map of the transient temperature field distribution, a thermogram of conductor deformation, and a vector map of current density.

[0142] The communication bus mentioned in the above electronic devices can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0143] Communication interface 802 is used for communication between the above-mentioned electronic device and other devices.

[0144] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0145] The processors mentioned above can be general-purpose processors, including central processing units, network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits, field-programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0146] Example 10: Based on the above embodiments, this invention also provides a computer-readable storage medium storing a computer program, which is processed by the above-described grounding wire thermal stability verification method based on multi-physics coupling.

[0147] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or its equivalents are included in this invention.

[0148] The embodiments described in this invention are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0149] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0150] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0151] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0152] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for verifying the thermal stability of a grounding wire based on multi-physics coupling, characterized in that, include: The time-domain waveform of the short-circuit current is captured at a specific node of the substation grounding wire to generate a dynamic current sequence; Based on the dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire, the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire are output using an electromagnetic-thermal-mechanical multiphysics coupling simulation model. Based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, the thermal stability of the grounding wire is checked, and the check result is output.

2. The method as described in claim 1, characterized in that, The electromagnetic-thermal-mechanical multiphysics coupling simulation model includes an electromagnetic-thermal coupling model and a thermo-mechanical coupling model incorporating the coefficient of thermal expansion. Based on the dynamic current sequence and pre-stored dimensions and material properties of the grounding wire, the electromagnetic-thermal-mechanical multiphysics coupling simulation model is used to output the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire, including: Based on the dynamic current sequence and the pre-stored dimensions and material properties of the grounding wire, the electromagnetic-thermal coupling model is solved using the finite element method to obtain the transient distribution of the temperature field caused by Joule heating. Based on the aforementioned dimensional material properties, the thermo-mechanical coupling model is solved using the thermo-elastic-plastic theory to obtain the conductor deformation of the grounding wire caused by temperature rise; The actual cross-sectional area of ​​the grounding wire is determined based on the conductor deformation. Based on the dynamic current sequence, the dimensional material properties, and the transient temperature field distribution, combined with the adaptive equivalent duration of the grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated.

3. The method as described in claim 2, characterized in that, The electromagnetic-thermal coupling model satisfies the following formula: ， in, For curl operator, For electric field strength, The magnetic flux density generated by the dynamic current sequence is given by t, where t represents time, T is the temperature field, and k is the thermal conductivity. Joule heating is given, and ρ is the resistivity related to the material properties of the stated dimensions. This refers to the current density corresponding to the dynamic current sequence. c is the material density related to the material properties of the stated dimensions, and c is the specific heat capacity related to the material properties of the stated dimensions. This represents the transient distribution of the temperature field caused by Joule heating; The thermo-mechanical coupling model satisfies the following formula: Where σ is stress, The elastic modulus is related to the material properties of the stated dimensions. For conductor deformation, ΔT is the temperature rise. is the coefficient of thermal expansion.

4. The method as described in claim 2, characterized in that, Based on the dynamic current sequence, the dimensional material properties, and the transient temperature field distribution, combined with the adaptive equivalent duration of the grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated, including: Based on the aforementioned dimensional material properties and the aforementioned transient temperature field distribution, the thermal stability coefficient as a function of temperature is determined; Based on the dynamic current sequence and the thermal stability coefficient, and combined with the adaptive equivalent duration of grounding fault, the dynamic minimum cross-sectional area curve of the grounding wire is calculated.

5. The method as described in claim 4, characterized in that, The process of obtaining the adaptive ground fault equivalent duration includes: Based on the operating logic of the protection devices in the substation, the equivalent duration of the ground fault is adaptively adjusted. If the operating logic of the protection device includes dual protection and circuit breaker failure protection, then the adaptive ground fault equivalent duration satisfies the following formula: If the operating logic of the protection device includes fast-acting main protection, backup protection, and automatic reclosing, then the adaptive equivalent duration of the ground fault satisfies the following formula: in, The adaptive ground fault equivalent duration, The duration of the primary protective action, For the failure protection action time, The circuit breaker opening time. This is the time for backup protection actions.

6. The method as described in claim 4 or 5, characterized in that, The dynamic minimum cross-sectional area curve of the grounding wire satisfies the following formula: in, This is the dynamic minimum cross-sectional area curve of the grounding wire. It is a dynamic current sequence. The thermal stability coefficient, The adaptive equivalent duration of a ground fault is given by t, which represents time.

7. The method as described in claim 1, characterized in that, The thermal stability check of the grounding wire is performed based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and the check result is output, including: If, within a continuous time range, the minimum cross-sectional area curve has a minimum cross-sectional area that is less than the actual cross-sectional area by a set proportion, then the thermal stability check of the grounding wire is determined to be unsatisfactory; otherwise, the thermal stability check of the grounding wire is determined to be satisfactory.

8. The method as described in claim 7, characterized in that, After performing thermal stability verification on the grounding wire based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and outputting the verification result, the process further includes: Dynamically display a comparison graph of the dynamic minimum cross-sectional area curve and the time-varying curve of the actual cross-sectional area; and / or This displays a three-dimensional field distribution map that overlays a cloud map of the transient temperature field distribution, a thermogram of conductor deformation, and a vector map of current density.

9. A grounding wire thermal stability verification system based on multi-physics coupling, characterized in that, include: The acquisition module is used to capture the time-domain waveform of short-circuit current at a specific node of the substation grounding wire and generate a dynamic current sequence. The simulation calculation module is used to output the dynamic minimum cross-sectional area curve and the actual cross-sectional area of ​​the grounding wire based on the dynamic current sequence and the pre-stored size and material properties of the grounding wire, using an electromagnetic-thermal-mechanical multiphysics coupling simulation model. The verification module is used to perform thermal stability verification on the grounding wire based on the dynamic minimum cross-sectional area curve and the actual cross-sectional area, and output the verification results.

10. An electronic device, characterized in that, The electronic device includes a processor and a memory. The memory is used to store program instructions, and the processor is used to execute the computer program stored in the memory to implement the steps of any of the above-described methods for verifying the thermal stability of grounding wires based on multi-physics coupling.

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