A method and system for three-dimensional simulation of arc in low-voltage air switch with arc extinguishing peak

Abstract

The application belongs to the technical field of arc simulation of low-voltage circuit breakers in power systems, and relates to a three-dimensional simulation method and system for low-voltage air switch arc containing arc extinguishing sharp peaks. The system obtains a three-dimensional simplified model of a low-voltage circuit breaker through a model acquisition module; performs local encryption processing on an arc movement path, a grid and a sheath layer area through a grid generation module; obtains a three-dimensional distribution of each parameter of the arc changing with time through an arc simulation module; corrects a sheath layer pressure drop model at an arc extinguishing stage according to experimental data through a sheath layer correction module; and compares and verifies simulation results obtained according to the corrected sheath layer pressure drop model with experimental data through a simulation result verification module, so as to ensure that the calculation results are close to actual arc characteristics. The application can effectively overcome the deficiency that the traditional simulation method is only applicable to the stable arc burning stage, and significantly improves the accuracy of arc voltage calculation at the arc extinguishing stage.

Description

Technical Field

[0001] This invention relates to the field of arc simulation technology for low-voltage circuit breakers in power systems, specifically to a three-dimensional simulation method and system for low-voltage air switch arcs containing arc extinction spikes. Background Technology

[0002] Low-voltage circuit breakers play a crucial role in power systems, and complex arc discharge phenomena occur during their breaking process. To study the characteristics of arc discharge in depth, current methods mainly employ experimental observation and mathematical modeling based on simulation software.

[0003] In the existing technology, most traditional electric arc simulation models are based on magnetohydrodynamic methods, which can reflect the stable arc characteristics after the formation of the arc well. However, for the arc extinction stage before the arc current crosses zero, especially the characteristics of the arc extinction peak, there is still a lack of effective simulation methods.

[0004] To this end, the invention patent with publication number CN115656809B discloses a digital twin model of a low-voltage AC arc, including: an arc physics experimental platform and a COMSOL arc simulation model; interactive mapping of arc information between the virtual and real platforms using wavelet energy spectrum feature values ​​of arc voltage; dynamically correcting simulation model parameters by collecting feature data of arc voltage changes in the arc physics experiment, making the simulation model closer to the actual arc movement process, and feeding the results obtained from the simulation model back to the physical platform of the arc experiment, thereby realizing dynamic simulation of the entire process of low-voltage AC arc.

[0005] The above-mentioned technical solutions have made progress in arc modeling and virtual-real fusion, but the following technical problems still exist: the core problem is that they still mainly rely on wavelet feature values ​​and experimental parameters for mapping and correction, which cannot accurately characterize the abrupt change characteristics of arc voltage during the arc extinction stage, and lack targeted simulation methods for arc behavior containing arc extinction peaks at the moment of arc extinction.

[0006] In view of this, it is very necessary to provide a three-dimensional simulation method and system for low-voltage air switch arc containing arc extinction spikes, so as to solve the above-mentioned defects in the prior art. Summary of the Invention

[0007] The purpose of this invention is to address the lack of targeted simulation for arc behavior containing extinction spikes, and to overcome the technical deficiencies of the existing technology, to provide a three-dimensional simulation method and system for low-voltage air switch arcs containing extinction spikes, thereby solving the aforementioned technical problems. To achieve the above objective, this invention provides the following technical solution: In a first aspect, the present invention provides a three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes, comprising the following steps: Step S1: The step of simplifying the low-voltage circuit breaker model is to simplify the actual three-dimensional model of the circuit breaker, retain the arc-extinguishing chamber structure and grid arrangement, while removing unnecessary details, and creating the fluid calculation domain, electromagnetic calculation domain and sheath region. Step S2: The step of generating the mesh model involves dividing the simplified circuit breaker model into meshes and performing local refinement processing on the main flow path of the electric arc and the grid and sheath areas. Step S3: The steps of electric arc simulation calculation are as follows: establish an electric arc simulation model based on the magnetohydrodynamic model, solve the momentum, mass, energy conservation equations, electromagnetic field equations and radiation equations, and set the corresponding temperature, pressure and electromagnetic boundary conditions to obtain the three-dimensional distribution of the electric arc parameters over time. Step S4: The sheath pressure drop correction step involves combining the simulation results and experimental measurement results obtained from the original sheath pressure drop model to correct the sheath pressure drop model, especially the sheath pressure drop model during the arc extinction stage, so that the corrected sheath pressure drop model is more in line with the actual arc characteristics. Step S5: The simulation result verification step compares the simulation results obtained by simulation calculation according to the modified sheath pressure drop model with the experimental measurement data. If the results are consistent, the final simulation conclusion is output; otherwise, return to step S4 for further correction.

[0008] Secondly, the present invention also provides a three-dimensional simulation system for low-voltage air switch arcs containing arc extinction spikes, comprising: The model acquisition module is used to acquire a simplified three-dimensional model of a low-voltage circuit breaker, retaining the arc-extinguishing chamber structure and grid arrangement, and creating a fluid computational domain, an electromagnetic computational domain, and a sheath region. The mesh generation module is used to generate meshes for the simplified model and to locally refine the main flow path of the electric arc, the grid plate and the sheath region to improve the accuracy of simulation calculations. The electric arc simulation module performs three-dimensional electric arc simulation based on the magnetohydrodynamic model, solves the momentum equation, mass equation, energy conservation equation, electromagnetic field equation and radiation equation, and sets temperature, pressure and electromagnetic boundary conditions. The sheath correction module corrects the sheath pressure drop model based on simulation and experimental measurement results, especially the sheath pressure drop model during the arc extinction stage, so that the corrected sheath pressure drop model is more in line with the actual arc characteristics. The simulation result verification module is used to compare the simulation results obtained by simulation calculation according to the modified sheath pressure drop model with the experimental measurement data. If the results are consistent, the final conclusion is output; otherwise, it returns to the sheath correction module for further optimization.

[0009] The modules work together to achieve three-dimensional simulation of the entire arc process of low-voltage air switch, optimization of simulation results, and accurate calculation of the arc voltage including the arc extinction peak during the arc extinction stage.

[0010] The beneficial effects of this invention are as follows: This invention proposes a three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes, achieving accurate simulation of the entire arc process. The method utilizes a simplified three-dimensional model of the low-voltage circuit breaker and a corresponding mesh model, combined with a magnetohydrodynamic arc simulation model. This allows for accurate reflection of the arc's flow characteristics, temperature distribution, electromagnetic field, and radiation characteristics in the simulation, providing a reliable three-dimensional data foundation for arc behavior analysis.

[0011] By modifying the sheath voltage drop model, this invention can accurately calculate the arc voltage containing the arc extinction peak, especially when the arc current decreases and external energy decays rapidly during the arc extinction phase. This significantly improves the accuracy and reliability of simulation results during the arc extinction phase. The modified sheath voltage drop model widens the hump region of the sheath voltage drop model curve, making the simulation results closer to the actual arc combustion process and providing a verifiable technical means for the performance evaluation of low-voltage circuit breakers.

[0012] Furthermore, this invention achieves closed-loop feedback optimization between simulation results and experimental results by having modules such as model acquisition, mesh generation, arc simulation, sheath correction, and simulation result verification work together. This makes the entire three-dimensional simulation process dynamic and controllable, providing a high-precision and high-efficiency technical means for the study of arc behavior.

[0013] Therefore, it is evident that the present invention has outstanding substantive features and significant progress compared with the prior art, and the beneficial effects of its implementation are also obvious. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0015] Figure 1 This is a flowchart of a three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes; Figure 2 This is a schematic diagram of a three-dimensional simulation system for a low-voltage air switch arc containing an arc extinction spike. Figure 3 This is a cross-sectional view of the sheath region; Figure 4 This is a curve of the sheath pressure drop model; Figure 5 This is a graph of the corrected sheath pressure drop model. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following implementation methods.

[0017] Example 1: like Figure 1 As shown in the figure, this embodiment provides a three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes, which includes the following steps: Step S1: The step of simplifying the low-voltage circuit breaker model is to simplify the actual three-dimensional model of the circuit breaker, retain the arc-extinguishing chamber structure and grid arrangement, while removing unnecessary details, and creating the fluid calculation domain, electromagnetic calculation domain and sheath region. Step S2: The step of generating the mesh model involves dividing the simplified circuit breaker model into meshes and performing local refinement processing on the main flow path of the electric arc and the grid and sheath areas. Step S3: The steps of electric arc simulation calculation are as follows: establish an electric arc simulation model based on the magnetohydrodynamic model, solve the momentum, mass, energy conservation equations, electromagnetic field equations and radiation equations, and set the corresponding temperature, pressure and electromagnetic boundary conditions to obtain the three-dimensional distribution of the electric arc parameters over time. Step S4: The sheath pressure drop correction step involves combining the simulation results and experimental measurement results obtained from the original sheath pressure drop model to correct the sheath pressure drop model, especially the sheath pressure drop model during the arc extinction stage, so that the corrected sheath pressure drop model is more in line with the actual arc characteristics. Step S5: The simulation result verification step compares the simulation results obtained by simulation calculation according to the modified sheath pressure drop model with the experimental measurement data. If the results are consistent, the final simulation conclusion is output; otherwise, return to step S4 for further correction.

[0018] Example 2: like Figure 1 As shown in the figure, this embodiment provides a three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes, which includes the following steps: Step S1: The step of simplifying the low-voltage circuit breaker model is to simplify the actual three-dimensional model of the circuit breaker, retain the arc-extinguishing chamber structure and grid arrangement, while removing unnecessary details, and creating the fluid calculation domain, electromagnetic calculation domain and sheath region. Step S2: The step of generating the mesh model involves dividing the simplified circuit breaker model into meshes and performing local refinement processing on the main flow path of the electric arc and the grid and sheath areas. Step S3: The steps of electric arc simulation calculation are as follows: establish an electric arc simulation model based on the magnetohydrodynamic model, solve the momentum, mass, energy conservation equations, electromagnetic field equations and radiation equations, and set the corresponding temperature, pressure and electromagnetic boundary conditions to obtain the three-dimensional distribution of the electric arc parameters over time. Step S4: The sheath pressure drop correction step involves combining the simulation results and experimental measurement results obtained from the original sheath pressure drop model to correct the sheath pressure drop model, especially the sheath pressure drop model during the arc extinction stage, so that the corrected sheath pressure drop model is more in line with the actual arc characteristics. Step S5: The simulation result verification step compares the simulation results obtained by simulation calculation according to the modified sheath pressure drop model with the experimental measurement data. If the results are consistent, the final simulation conclusion is output; otherwise, return to step S4 for further correction.

[0019] In step S1: Based on the actual three-dimensional model of the low-voltage circuit breaker, the circuit breaker model is simplified without changing the overall structure of the arc-extinguishing chamber or the airflow field within the chamber. Specific operations include: retaining the basic arc-extinguishing chamber structure; simplifying the inner wall structure of the chamber, discarding unnecessary details such as chamfers, screw holes, minor protrusions, and the wall itself; simplifying minor protrusions and chamfers without changing the arrangement, inclination, number, and position of the grid plates; creating the fluid computational domain and electromagnetic computational domain using Boolean operations; and creating the sheath region.

[0020] By simplifying the low-voltage circuit breaker model while retaining key arc-extinguishing structures and airflow characteristics, the accuracy and efficiency of subsequent arc simulation calculations can be guaranteed. This avoids the problem of lengthy or unstable simulation calculations caused by the complex structure of the circuit breaker, providing a reliable foundation for the simulation of the entire arc process.

[0021] Example 3: like Figure 1 As shown in the figure, this embodiment provides a three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes, which includes the following steps: Step S1: The step of simplifying the low-voltage circuit breaker model is to simplify the actual three-dimensional model of the circuit breaker, retain the arc-extinguishing chamber structure and grid arrangement, while removing unnecessary details, and creating the fluid calculation domain, electromagnetic calculation domain and sheath region. Step S2: The step of generating the mesh model involves dividing the simplified circuit breaker model into meshes and performing local refinement processing on the main flow path of the electric arc and the grid and sheath areas. Step S3: The steps of electric arc simulation calculation are as follows: establish an electric arc simulation model based on the magnetohydrodynamic model, solve the momentum, mass, energy conservation equations, electromagnetic field equations and radiation equations, and set the corresponding temperature, pressure and electromagnetic boundary conditions to obtain the three-dimensional distribution of the electric arc parameters over time. Step S4: The sheath pressure drop correction step involves combining the simulation results and experimental measurement results obtained from the original sheath pressure drop model to correct the sheath pressure drop model, especially the sheath pressure drop model during the arc extinction stage, so that the corrected sheath pressure drop model is more in line with the actual arc characteristics. Step S5: The simulation result verification step compares the simulation results obtained by simulation calculation according to the modified sheath pressure drop model with the experimental measurement data. If the results are consistent, the final simulation conclusion is output; otherwise, return to step S4 for further correction.

[0022] In step S1: Based on the actual three-dimensional model of the low-voltage circuit breaker, the circuit breaker model is simplified without changing the overall structure of the arc-extinguishing chamber or the airflow field within the chamber. Specific operations include: retaining the basic arc-extinguishing chamber structure; simplifying the inner wall structure of the chamber, discarding unnecessary details such as chamfers, screw holes, minor protrusions, and the wall itself; simplifying minor protrusions and chamfers without changing the arrangement, inclination, number, and position of the grid plates; creating the fluid computational domain and electromagnetic computational domain using Boolean operations; and creating the sheath region.

[0023] By simplifying the low-voltage circuit breaker model while retaining key arc-extinguishing structures and airflow characteristics, the accuracy and efficiency of subsequent arc simulation calculations can be guaranteed. This avoids the problem of lengthy or unstable simulation calculations caused by the complex structure of the circuit breaker, providing a reliable foundation for the simulation of the entire arc process.

[0024] In step S2, the created simplified 3D model of the low-voltage circuit breaker is meshed. To ensure the accuracy and efficiency of the simulation calculation, the meshing needs to consider both the number and quality of meshes. Local refinement is performed on the mesh in the main fluid regions within the arc motion path to improve the mesh quality of the grid plates and sheath.

[0025] By rationally dividing the mesh and refining the local grid, the spatial distribution of fluid, thermal field and electromagnetic field can be accurately captured during the electric arc simulation calculation, thereby obtaining more reliable three-dimensional simulation data and improving the fit of the simulation results to the actual electric arc behavior.

[0026] Example 4: like Figure 1 As shown in the figure, this embodiment provides a three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes, which includes the following steps: Step S1: The step of simplifying the low-voltage circuit breaker model is to simplify the actual three-dimensional model of the circuit breaker, retain the arc-extinguishing chamber structure and grid arrangement, while removing unnecessary details, and creating the fluid calculation domain, electromagnetic calculation domain and sheath region. Step S2: The step of generating the mesh model involves dividing the simplified circuit breaker model into meshes and performing local refinement processing on the main flow path of the electric arc and the grid and sheath areas. Step S3: The steps of electric arc simulation calculation are as follows: establish an electric arc simulation model based on the magnetohydrodynamic model, solve the momentum, mass, energy conservation equations, electromagnetic field equations and radiation equations, and set the corresponding temperature, pressure and electromagnetic boundary conditions to obtain the three-dimensional distribution of the electric arc parameters over time. Step S4: The sheath pressure drop correction step involves combining the simulation results and experimental measurement results obtained from the original sheath pressure drop model to correct the sheath pressure drop model, especially the sheath pressure drop model during the arc extinction stage, so that the corrected sheath pressure drop model is more in line with the actual arc characteristics. Step S5: The simulation result verification step compares the simulation results obtained by simulation calculation according to the modified sheath pressure drop model with the experimental measurement data. If the results are consistent, the final simulation conclusion is output; otherwise, return to step S4 for further correction.

[0027] In step S1: Based on the actual three-dimensional model of the low-voltage circuit breaker, the circuit breaker model is simplified without changing the overall structure of the arc-extinguishing chamber or the airflow field within the chamber. Specific operations include: retaining the basic arc-extinguishing chamber structure; simplifying the inner wall structure of the chamber, discarding unnecessary details such as chamfers, screw holes, minor protrusions, and the wall itself; simplifying minor protrusions and chamfers without changing the arrangement, inclination, number, and position of the grid plates; creating the fluid computational domain and electromagnetic computational domain using Boolean operations; and creating the sheath region.

[0028] By simplifying the low-voltage circuit breaker model while retaining key arc-extinguishing structures and airflow characteristics, the accuracy and efficiency of subsequent arc simulation calculations can be guaranteed. This avoids the problem of lengthy or unstable simulation calculations caused by the complex structure of the circuit breaker, providing a reliable foundation for the simulation of the entire arc process.

[0029] In step S2, the created simplified 3D model of the low-voltage circuit breaker is meshed. To ensure the accuracy and efficiency of the simulation calculation, the meshing needs to consider both the number and quality of meshes. Local refinement is performed on the mesh in the main fluid regions within the arc motion path to improve the mesh quality of the grid plates and sheath.

[0030] By rationally dividing the mesh and refining the local grid, the spatial distribution of fluid, thermal field and electromagnetic field can be accurately captured during the electric arc simulation calculation, thereby obtaining more reliable three-dimensional simulation data and improving the fit of the simulation results to the actual electric arc behavior.

[0031] In step S3: an arc simulation model based on magnetohydrodynamics is established on the Fluent platform. The combustion process of arc plasma is highly dynamic and multi-scale, involving particle recombination, decomposition, ionization and aggregation at the microscopic level, and energy transfer processes such as radiation, conduction and convection at the macroscopic level. It also involves the complex coupling of multiple physical fields such as airflow field, thermal field and electromagnetic field.

[0032] To reasonably simplify the model and maintain the validity of the calculation results, certain assumptions and simplifications need to be made to the actual electric arc model, ignoring factors with minor influences, focusing on the main contradictions, and creating appropriate mathematical equations to accurately describe the electric arc. These include: the electric arc satisfies local thermodynamic equilibrium conditions; physical properties such as density, thermal conductivity, specific heat capacity, and viscosity change with temperature and pressure; the flow characteristics of the electric arc in the arc-extinguishing chamber are turbulent, the fluid motion is random, and pressure and velocity move irregularly with time and space; and the simulation does not consider the corrosive effect of the electric arc on the metal contacts and the vessel walls.

[0033] Based on this, the changes of various parameters of the electric arc in the arc extinguishing chamber with time are described by the conservation equations of momentum, mass, energy, electromagnetic field, and radiation.

[0034] First, the mass conservation equation is as follows:

[0035] Parameter explanation: ρ is the fluid density / kg·m -3 t is time in seconds; U is the velocity vector in meters per second. -1 .

[0036] Next, the momentum change of the electric arc is described by the momentum conservation equations in three directions, as follows:

[0037]

[0038]

[0039] Parameter explanation: ρ is the fluid density / kg·m -3 u, v, and w are the flow velocities in the x, y, and z directions, respectively, in m / s. -1 η is the viscosity coefficient / kg·(m s) -1 p is the fluid element pressure / Pa; , , These are the generalized source terms in the x, y, and z directions, respectively.

[0040] Generalized source term , , This plays a crucial role in the process. The expansion of the generalized source term is shown in the formula, which includes not only the fluid transport term but also the electromagnetic force component. , , This is to ensure the true response of the electric arc when it is subjected to an external electromagnetic field.

[0041] Among them, the generalized source term , , The defining formula is:

[0042]

[0043]

[0044] Parameter description: λ is thermal conductivity / W·(m·K) -1 ; , , The components of electromagnetic force are in the x, y, and z directions, respectively.

[0045] To further characterize the properties of an electric arc under the influence of electromagnetic forces, the Lorentz force formula is introduced, which reveals the current density ( , , ) and magnetic field strength ( , , The interaction between the electric arc and its constituent elements. Therefore, although the electric arc as a whole exhibits electrical neutrality, the influence of the magnetic field on its infinitesimal motion is far greater than the electric field effect; thus, the Lorentz force must be explicitly considered in the simulation. The formula for calculating the Lorentz force is shown below:

[0046]

[0047]

[0048] Parameter description: , , Current density in the x, y, and z directions (A·m) -2 ; , , denoted as magnetic field strength in the x, y, and z directions, respectively, in T.

[0049] At the energy transfer level, the energy conservation equation is adopted. This equation incorporates various factors such as enthalpy, specific heat at isobaric pressure, energy source term, fluid viscous dissipation, conductivity, and electric field strength, while also introducing radiative energy to ensure a complete description of energy exchange. The formula for the energy conservation equation is as follows:

[0050]

[0051] Parameter description: h is enthalpy / kJ·kg; Specific heat at constant pressure / J·(kg) K) -1 ; φ is the energy source term; φ is the fluid viscous dissipation; σ is the conductivity / S·m -1 E is the electric field strength / V·m -1 qrad represents the radiant energy per J.

[0052] When an electric current passes through plasma, it triggers a series of complex electromagnetic effects. To address the electromagnetic field problem, Maxwell's equations are used for analysis. Maxwell's equations are as follows:

[0053]

[0054]

[0055] Parameter description: B is magnetic flux density / T; μ is magnetic permeability / H·m -1 .

[0056] The magnetic field is solved using the vector magnetic potential method: A is the vector magnetic potential / Wb·m -1 .

[0057] The corresponding electric field distribution is determined by and The electric field is given, where the potential φ (in V) and the vector magnetic potential A together determine the spatiotemporal distribution of the electric field.

[0058] In the radiation process, a simplified T4 model is used, and the expression for radiation energy is: This model is based on Planck's blackbody radiation law and uses the Stefan-Boltzmann constant α, correction factor β, and absorption coefficient k to correct the radiation intensity, thus reflecting the high-temperature radiation characteristics of the electric arc well.

[0059] After establishing the equation set, the arc mathematical model needs to be applied to the geometric model, and corresponding boundary conditions need to be set. Specifically: the contact surface between the anode and cathode contacts and the fluid constitutes the temperature boundary, which is constrained by a one-dimensional heat conduction equation, and the highest temperature at the boundary is lower than the evaporation temperature of the vessel wall; the arc-extinguishing chamber outlet is the pressure boundary, set to 1 atm; regarding the electromagnetic field boundary conditions, the current output terminal of the cathode contact is set to zero potential, and a set current value is applied as a load to the current input terminal of the anode contact. For the model's symmetry plane and other boundaries, the boundary conditions defined by the formulas are satisfied respectively, thereby ensuring the rationality of the magnetic field and electric field distribution.

[0060] The one-dimensional heat conduction equation is: Parameter description: q is the heat flux density at the boundary / W·m -2 T represents the internal temperature of the vessel wall in K. d represents the external temperature of the vessel wall in K; d represents the thickness of the vessel wall in m.

[0061] For the plane of symmetry of the model, the boundary conditions of the magnetic field are: , v is the magnetoresistive density / m·H -1 A represents the magnetic vector potential.

[0062] The remaining boundaries of the electromagnetic solution domain satisfy the following conditions: ,

[0063] This step can accurately describe the three-dimensional distribution of various arc parameters over time, providing comprehensive and reliable simulation data for analyzing the entire arc process of low-voltage air switches, especially supporting the arc characteristics during the ignition and extinction stages.

[0064] Example 5: like Figure 1 As shown in the figure, this embodiment provides a three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes, which includes the following steps: Step S1: The step of simplifying the low-voltage circuit breaker model is to simplify the actual three-dimensional model of the circuit breaker, retain the arc-extinguishing chamber structure and grid arrangement, while removing unnecessary details, and creating the fluid calculation domain, electromagnetic calculation domain and sheath region. Step S2: The step of generating the mesh model involves dividing the simplified circuit breaker model into meshes and performing local refinement processing on the main flow path of the electric arc and the grid and sheath areas. Step S3: The steps of electric arc simulation calculation are as follows: establish an electric arc simulation model based on the magnetohydrodynamic model, solve the momentum, mass, energy conservation equations, electromagnetic field equations and radiation equations, and set the corresponding temperature, pressure and electromagnetic boundary conditions to obtain the three-dimensional distribution of the electric arc parameters over time. Step S4: The sheath pressure drop correction step involves combining the simulation results and experimental measurement results obtained from the original sheath pressure drop model to correct the sheath pressure drop model, especially the sheath pressure drop model during the arc extinction stage, so that the corrected sheath pressure drop model is more in line with the actual arc characteristics. Step S5: The simulation result verification step compares the simulation results obtained by simulation calculation according to the modified sheath pressure drop model with the experimental measurement data. If the results are consistent, the final simulation conclusion is output; otherwise, return to step S4 for further correction.

[0065] In step S1: Based on the actual three-dimensional model of the low-voltage circuit breaker, the circuit breaker model is simplified without changing the overall structure of the arc-extinguishing chamber or the airflow field within the chamber. Specific operations include: retaining the basic arc-extinguishing chamber structure; simplifying the inner wall structure of the chamber, discarding unnecessary details such as chamfers, screw holes, minor protrusions, and the wall itself; simplifying minor protrusions and chamfers without changing the arrangement, inclination, number, and position of the grid plates; creating the fluid computational domain and electromagnetic computational domain using Boolean operations; and creating the sheath region.

[0066] By simplifying the low-voltage circuit breaker model while retaining key arc-extinguishing structures and airflow characteristics, the accuracy and efficiency of subsequent arc simulation calculations can be guaranteed. This avoids the problem of lengthy or unstable simulation calculations caused by the complex structure of the circuit breaker, providing a reliable foundation for the simulation of the entire arc process.

[0067] In step S2, the created simplified 3D model of the low-voltage circuit breaker is meshed. To ensure the accuracy and efficiency of the simulation calculation, the meshing needs to consider both the number and quality of meshes. Local refinement is performed on the mesh in the main fluid regions within the arc motion path to improve the mesh quality of the grid plates and sheath.

[0068] By rationally dividing the mesh and refining the local grid, the spatial distribution of fluid, thermal field and electromagnetic field can be accurately captured during the electric arc simulation calculation, thereby obtaining more reliable three-dimensional simulation data and improving the fit of the simulation results to the actual electric arc behavior.

[0069] In step S3: an arc simulation model based on magnetohydrodynamics is established on the Fluent platform. The combustion process of arc plasma is highly dynamic and multi-scale, involving particle recombination, decomposition, ionization and aggregation at the microscopic level, and energy transfer processes such as radiation, conduction and convection at the macroscopic level. It also involves the complex coupling of multiple physical fields such as airflow field, thermal field and electromagnetic field.

[0070] To reasonably simplify the model and maintain the validity of the calculation results, certain assumptions and simplifications need to be made to the actual electric arc model, ignoring factors with minor influences, focusing on the main contradictions, and creating appropriate mathematical equations to accurately describe the electric arc. These include: the electric arc satisfies local thermodynamic equilibrium conditions; physical properties such as density, thermal conductivity, specific heat capacity, and viscosity change with temperature and pressure; the flow characteristics of the electric arc in the arc-extinguishing chamber are turbulent, the fluid motion is random, and pressure and velocity move irregularly with time and space; and the simulation does not consider the corrosive effect of the electric arc on the metal contacts and the vessel walls.

[0071] Based on this, the changes of various parameters of the electric arc in the arc extinguishing chamber with time are described by the conservation equations of momentum, mass, energy, electromagnetic field, and radiation.

[0072] First, the mass conservation equation is as follows:

[0073] Parameter explanation: ρ is the fluid density / kg·m -3 t is time in seconds; U is the velocity vector in meters per second. -1 .

[0074] Next, the momentum change of the electric arc is described by the momentum conservation equations in three directions, as follows:

[0075]

[0076]

[0077] Parameter explanation: ρ is the fluid density / kg·m -3 u, v, and w are the flow velocities in the x, y, and z directions, respectively, in m / s. -1 η is the viscosity coefficient / kg·(m s) -1 p is the fluid element pressure / Pa; , , These are the generalized source terms in the x, y, and z directions, respectively.

[0078] Generalized source term , , This plays a crucial role in the process. The expansion of the generalized source term is shown in the formula, which includes not only the fluid transport term but also the electromagnetic force component. , , This is to ensure the true response of the electric arc when it is subjected to an external electromagnetic field.

[0079] Among them, the generalized source term , , The defining formula is:

[0080]

[0081]

[0082] Parameter description: λ is thermal conductivity / W·(m·K) -1 ; , , The components of electromagnetic force are in the x, y, and z directions, respectively.

[0083] To further characterize the properties of an electric arc under the influence of electromagnetic forces, the Lorentz force formula is introduced, which reveals the current density ( , , ) and magnetic field strength ( , , The interaction between the electric arc and its constituent elements. Therefore, although the electric arc as a whole exhibits electrical neutrality, the influence of the magnetic field on its infinitesimal motion is far greater than the electric field effect; thus, the Lorentz force must be explicitly considered in the simulation. The formula for calculating the Lorentz force is shown below:

[0084]

[0085]

[0086] Parameter description: , , Current density in the x, y, and z directions (A·m) -2 ; , , denoted as magnetic field strength in the x, y, and z directions, respectively, in T.

[0087] At the energy transfer level, the energy conservation equation is adopted. This equation incorporates various factors such as enthalpy, specific heat at isobaric pressure, energy source term, fluid viscous dissipation, conductivity, and electric field strength, while also introducing radiative energy to ensure a complete description of energy exchange. The formula for the energy conservation equation is as follows:

[0088]

[0089] Parameter description: h is enthalpy / kJ·kg; Specific heat at constant pressure / J·(kg) K) -1 ; φ is the energy source term; φ is the fluid viscous dissipation; σ is the conductivity / S·m -1 E is the electric field strength / V·m -1 qrad represents the radiant energy per J.

[0090] When an electric current passes through plasma, it triggers a series of complex electromagnetic effects. To address the electromagnetic field problem, Maxwell's equations are used for analysis. Maxwell's equations are as follows:

[0091]

[0092]

[0093] Parameter description: B is magnetic flux density / T; μ is magnetic permeability / H·m -1 .

[0094] The magnetic field is solved using the vector magnetic potential method: A is the vector magnetic potential / Wb·m -1 .

[0095] The corresponding electric field distribution is determined by and The electric field is given, where the potential φ (in V) and the vector magnetic potential A together determine the spatiotemporal distribution of the electric field.

[0096] In the radiation phase, a simplified T4 model is adopted. The T4 model refers to an approximate calculation method for arc radiation based on Planck's blackbody radiation law. Its core idea is that the radiative energy of the arc plasma is proportional to the fourth power of its absolute temperature, expressed as: This model is based on Planck's blackbody radiation law, and the radiation intensity is corrected using the Stefan-Boltzmann constant α, the correction factor β, and the absorption coefficient k. T is the temperature inside the container wall in K. The value is the temperature outside the vessel wall in K, which can effectively reflect the high-temperature radiation characteristics of the electric arc.

[0097] After establishing the equation set, the arc mathematical model needs to be applied to the geometric model, and corresponding boundary conditions need to be set. Specifically: the contact surface between the anode and cathode contacts and the fluid constitutes the temperature boundary, which is constrained by a one-dimensional heat conduction equation, and the highest temperature at the boundary is lower than the evaporation temperature of the vessel wall; the arc-extinguishing chamber outlet is the pressure boundary, set to 1 atm; regarding the electromagnetic field boundary conditions, the current output terminal of the cathode contact is set to zero potential, and a set current value is applied as a load to the current input terminal of the anode contact. For the model's symmetry plane and other boundaries, the boundary conditions defined by the formulas are satisfied respectively, thereby ensuring the rationality of the magnetic field and electric field distribution.

[0098] The one-dimensional heat conduction equation is: Parameter description: q is the heat flux density at the boundary / W·m -2 T represents the internal temperature of the vessel wall in K. d represents the external temperature of the vessel wall in K; d represents the thickness of the vessel wall in m.

[0099] For the plane of symmetry of the model, the boundary conditions of the magnetic field are: , v is the magnetoresistive density / m·H -1 A represents the magnetic vector potential.

[0100] The remaining boundaries of the electromagnetic solution domain satisfy the following conditions: ,

[0101] This step can accurately describe the three-dimensional distribution of various arc parameters over time, providing comprehensive and reliable simulation data for analyzing the entire arc process of low-voltage air switches, especially supporting the arc characteristics during the ignition and extinction stages.

[0102] In step S4, during the arc-extinguishing chamber of the circuit breaker, a thin layer, known as the sheath region, forms between the plasma and the metal surface when the grid plates cut the arc. A cross-sectional view of the sheath region is shown below. Figure 3 As shown in the figure. Because this region is in a non-equilibrium state, it has a significant impact on the arc voltage. To describe the relationship between sheath voltage drop and current density, the concept of effective conductivity is adopted, and a model is established as follows: The relationship is shown below; where J is the current density; Δy is the sheath thickness, taken as 0.1 mm; and U is the sheath voltage drop.

[0103] When the current density is low, the sheath voltage drop is close to zero; as the current density gradually increases, a voltage peak appears in the curve; if the current continues to increase, the sheath voltage tends to be constant. Turbulence coefficients and radiation significantly affect the simulated arc voltage, especially during the arcing and extinction stages, where the radiation coefficient has a particularly significant impact. Therefore, in actual simulations, special attention needs to be paid to the influence of the radiation coefficient on the simulated voltage. Based on the above conditions, Fluent was used to perform numerical calculations on the circuit breaker as a whole.

[0104] The original sheath voltage drop model is only applicable to calculating the arc voltage before arc extinction, and it has inaccuracies for the arc extinction stage. The original sheath voltage drop model curve is shown below. Figure 4 As shown, when the arc current drops below 100 amperes, the energy of the externally input arc decreases rapidly, and the arc temperature decays sharply. At this point, the non-equilibrium effect in the sheath region becomes more significant, leading to a rapid rise in arc voltage. To address this characteristic, the original sheath voltage drop model during the arc extinction stage is modified by increasing the sheath voltage drop value before the current crosses zero. The specific increase in the sheath voltage drop model is calculated based on experimental data; the modification can be expressed by the formula:

[0105]

[0106] Parameter description: It is the experimentally measured voltage value in V; It represents the simulated voltage value in V; m is the number of arc roots (number of cathode arc roots + number of anode arc roots). It is the corrected sheath pressure drop value / V.

[0107] Using the simulated current density during the arc extinction phase as the abscissa, and... Using the vertical axis as the ordinate, the hump region of the sheath pressure drop model curve is widened to obtain the corrected sheath pressure drop model. Finally, the corrected sheath pressure drop model is substituted into the simulation model for calculation, and the corrected sheath pressure drop model curve is shown below. Figure 5 As shown, the results indicate that the modified sheath pressure drop model can significantly improve the accuracy of arc voltage calculation during the arc extinction stage.

[0108] By modifying the sheath voltage drop model, the shortcomings of the original sheath voltage drop model, which is only applicable to the arcing stage and has deviations in the arc extinguishing stage, can be effectively overcome. This makes the simulated voltage curve more consistent with the experimental measurement results, thereby significantly improving the calculation accuracy of the arc voltage in the arc extinguishing stage.

[0109] Example 6: like Figure 2 As shown in the figure, this embodiment provides a three-dimensional simulation system for low-voltage air switch arcs containing extinction spikes, comprising: Model acquisition module 1 is used to acquire a simplified 3D model of the low-voltage circuit breaker, retaining the arc-extinguishing chamber structure and grid arrangement while removing unnecessary details within the cavity, and creating fluid computational domains, electromagnetic computational domains, and sheath regions. Specific operations include: retaining the basic arc-extinguishing chamber structure; simplifying the internal wall structure of the cavity, discarding unnecessary details such as chamfers, screw holes, minor protrusions, and the wall itself; simplifying minor protrusions and chamfers without changing the grid arrangement, inclination, number, or position; using Boolean operations to create fluid and electromagnetic computational domains, and establishing the sheath region.

[0110] By simplifying the low-voltage circuit breaker model while retaining key arc-extinguishing structures and airflow characteristics, the accuracy and efficiency of subsequent arc simulation calculations can be guaranteed. This avoids lengthy or unstable simulation calculations caused by the complex structure of the circuit breaker, providing a reliable foundation for the simulation of the entire arc process.

[0111] Mesh generation module 2 is used to generate a mesh for the simplified 3D model of the low-voltage circuit breaker, and to locally refine the mesh in the main flow path of the arc, the grid plate, and the sheath region to ensure the accuracy and efficiency of the simulation calculation. Mesh generation needs to balance the quantity and quality of the meshes, and optimization is performed in the electromagnetic region, fluid domain, and grid plate region. Local refinement is applied to the mesh in the main fluid region within the arc movement path, and the mesh quality in the grid plate and sheath region is improved.

[0112] By rationally dividing the mesh and refining the local mesh, the spatial distribution of fluid, thermal field and electromagnetic field can be accurately captured during the electric arc simulation calculation, thereby obtaining more reliable three-dimensional simulation data, improving the fit of the simulation results to the actual electric arc behavior, and taking into account both calculation accuracy and efficiency.

[0113] The arc simulation module 3 performs three-dimensional arc simulation based on a magnetohydrodynamic model, solving the conservation equations for momentum, mass, and energy, as well as the electromagnetic field and radiation equations. It sets corresponding temperature, pressure, and electromagnetic boundary conditions to obtain the three-dimensional distribution of arc parameters over time. Specifically, the arc plasma satisfies local thermodynamic equilibrium conditions, and physical properties such as density, thermal conductivity, specific heat capacity, and viscosity change with temperature and pressure. The arc flow in the arc-extinguishing chamber is turbulent, with random fluid motion; pressure and velocity move irregularly over time and space. The simulation does not consider the erosive effect of the arc on the metal contacts and the vessel walls. The temperature boundary is set at the contact surface between the anode and cathode contacts and the fluid, using a one-dimensional heat conduction equation; the highest temperature at the boundary is lower than the evaporation temperature of the vessel wall. The pressure boundary is the arc-extinguishing chamber outlet. The electromagnetic boundary sets the current inflow and outflow ends, and the magnetic field is solved using the magnetic vector potential method, with corresponding magnetic field boundary conditions set on the symmetry plane. The turbulence model uses the standard k-epsilon model, and the radiation process uses a simplified T4 model, focusing on the influence of the radiation coefficient on the simulation voltage.

[0114] By establishing a magnetohydrodynamic model and combining it with temperature, pressure, and electromagnetic boundary conditions, the multi-physics coupling characteristics of the arc formation, arc ignition, and arc extinction stages can be fully described, enabling accurate three-dimensional simulation of the entire arc process of a low-pressure air switch, and providing data for subsequent sheath pressure drop correction.

[0115] The sheath correction module 4 corrects the sheath voltage drop model based on simulation and experimental results, especially for the sheath voltage drop model during the arc extinction stage. Specifically, this includes: performing simulation calculations based on the original sheath voltage drop model and comparing the results with experimental data; during the arc extinction stage, when the arc current drops below 100 amperes, the arc temperature decays rapidly, and the sheath non-equilibrium effect becomes significant, causing the arc voltage to rise rapidly; increasing the sheath voltage drop value before the current crosses zero to correct the sheath curve, with the increase calculated based on experimental data; and widening the hump region of the sheath voltage drop model curve to obtain the corrected sheath voltage drop model.

[0116] By modifying the sheath voltage drop model, the accuracy of arc voltage calculation during the arc extinction stage can be significantly improved, making the simulation results closer to the actual arc characteristics. In particular, for the voltage fluctuations at the arc extinction peak, accurate simulation of the entire arc three-dimensional simulation can be achieved.

[0117] The simulation result verification module 5 is used to compare the simulation results obtained by simulation calculation according to the modified sheath pressure drop model with the experimental measurement data. If the results are consistent, the final conclusion is output; otherwise, it is returned to the sheath correction module for further optimization.

[0118] By comparing simulation results with experimental measurements, the accuracy of the modified sheath pressure drop model can be verified, ensuring the reliability of the final simulation conclusions and providing a scientific basis for the design, analysis, and optimization of low-voltage circuit breakers.

[0119] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The methods disclosed in the embodiments are described simply because they correspond to the systems disclosed in the embodiments; relevant details can be found in the method section.

[0120] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0121] In the embodiments provided by this invention, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between systems or units may be electrical, mechanical, or other forms.

[0122] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0123] In addition, the functional modules in the various embodiments of the present invention can be integrated into one processing unit, or each module can exist physically separately, or two or more modules can be integrated into one unit.

[0124] Similarly, in the various embodiments of the present invention, each processing unit can be integrated into a functional module, or each processing unit can exist physically, or two or more processing units can be integrated into a functional module.

[0125] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0126] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0127] The above-disclosed embodiments are merely preferred embodiments of the present invention, but the present invention is not limited thereto. Any non-creative variations that can be conceived by those skilled in the art, as well as any improvements and modifications made without departing from the principles of the present invention, should fall within the protection scope of the present invention.

Claims

1. A three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes, characterized in that, Includes the following steps: Step S1: The step of simplifying the low-voltage circuit breaker model is to simplify the actual three-dimensional model of the circuit breaker, retain the arc-extinguishing chamber structure and grid arrangement, while removing unnecessary details, and creating the fluid calculation domain, electromagnetic calculation domain and sheath region. Step S2: The step of generating the mesh model involves dividing the simplified circuit breaker model into meshes and performing local refinement processing on the main flow path of the electric arc and the grid and sheath areas. Step S3: The steps of electric arc simulation calculation are as follows: establish an electric arc simulation model based on the magnetohydrodynamic model, solve the momentum, mass, energy conservation equations, electromagnetic field equations and radiation equations, and set the corresponding temperature, pressure and electromagnetic boundary conditions to obtain the three-dimensional distribution of the electric arc parameters over time. Step S4: The sheath pressure drop correction step involves combining the simulation results and experimental measurement results obtained from the original sheath pressure drop model to correct the sheath pressure drop model, especially the sheath pressure drop model during the arc extinction stage, so that the corrected sheath pressure drop model is more in line with the actual arc characteristics. Step S5: The simulation result verification step compares the simulation results obtained by simulation calculation according to the modified sheath pressure drop model with the experimental measurement data. If the results are consistent, the final simulation conclusion is output; otherwise, return to step S4 for further correction.

2. The three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes according to claim 1, characterized in that, In step S1: Based on the actual three-dimensional model of the low-voltage circuit breaker, the circuit breaker model is simplified without changing the overall structure of the arc-extinguishing chamber or the airflow field inside the chamber.

3. A three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes according to claim 1 or 2, characterized in that, Step S1 includes retaining the basic arc-extinguishing chamber structure; simplifying the inner wall structure of the cavity and discarding unnecessary details inside the cavity; simplifying minor protrusions and chamfers without changing the grid arrangement, inclination, number and position; creating the fluid computing domain and electromagnetic computing domain using Boolean operations; and creating the sheath region.

4. The three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes according to claim 1, characterized in that, In step S3: an electric arc simulation model based on magnetohydrodynamics is established on the Fluent platform. Assumptions are made and simplified on the actual electric arc model, and mathematical equations are created to accurately describe the electric arc. The flow characteristics of the electric arc in the arc-extinguishing chamber are turbulent, and the fluid motion is random. The pressure and velocity move irregularly with time and space.

5. The three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes according to claim 4, characterized in that, In step S3, the changes of various parameters of the electric arc in the arc extinguishing chamber over time are described by the conservation equations of momentum, mass, energy, electromagnetic field, and radiation.

6. The three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes according to claim 5, characterized in that, In step S3: the electric arc mathematical model is applied to the geometric model, and corresponding boundary conditions are set for it. Specifically: the contact surface between the anode and cathode contacts and the fluid constitutes a temperature boundary, which is constrained by a one-dimensional heat conduction equation, and the highest temperature at the boundary is lower than the evaporation temperature of the vessel wall; the outlet of the arc-extinguishing chamber is a pressure boundary, set to 1 atm; in terms of electromagnetic field boundary conditions, the current output terminal of the cathode contact is set to zero potential, and a set current value is applied as a load to the current input terminal of the anode contact.

7. The three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes according to claim 6, characterized in that, In step S4, the original sheath voltage drop model during the arc extinction stage is modified by increasing the sheath voltage drop value before the current crosses zero.

8. The three-dimensional simulation method for low-voltage air switch arcs containing extinction spikes according to claim 7, characterized in that, The correction can be expressed by the following formula: 。 9. A three-dimensional simulation system for low-voltage air switch arc containing extinction spikes, characterized in that, The system adopts a three-dimensional simulation method for low-voltage air switch arc with extinguishing spike as described in any one of claims 1 to 8. The system includes a model acquisition module (1), a mesh generation module (2), an arc simulation module (3), a sheath correction module (4), and a simulation result verification module (5). The model acquisition module (1) is used to acquire a three-dimensional simplified model of the low-voltage circuit breaker, retain the arc-extinguishing chamber structure and grid arrangement, and create a fluid calculation domain, an electromagnetic calculation domain and a sheath region. The mesh generation module (2) is used to divide the simplified model into meshes and to locally refine the main flow path of the electric arc, the grid plate and the sheath region to improve the accuracy of simulation calculation. The electric arc simulation module (3) performs three-dimensional electric arc simulation based on the magnetohydrodynamic model, solves the momentum equation, mass equation, energy conservation equation, electromagnetic field equation and radiation equation, and sets temperature, pressure and electromagnetic boundary conditions. The sheath correction module (4) corrects the sheath pressure drop model based on the simulation results and experimental measurement results, especially the sheath pressure drop model in the arc extinction stage, so that the corrected sheath pressure drop model is more in line with the actual arc characteristics. The simulation result verification module (5) is used to compare the simulation results obtained by simulation calculation according to the modified sheath pressure drop model with the experimental measurement data. If the results are consistent, the final conclusion is output; otherwise, it returns to the sheath correction module (4) for further optimization.

10. A three-dimensional simulation system for low-voltage air switch arcs containing extinction spikes according to claim 9, characterized in that, The specific operations of the model acquisition module (1) include: retaining the basic arc-extinguishing chamber structure; simplifying the internal wall structure of the cavity; simplifying minor protrusions and chamfers without changing the grid arrangement, inclination, quantity and position; using Boolean operations to create the fluid calculation domain and electromagnetic calculation domain, and establishing the sheath region; The electric arc simulation module (3) specifically includes: the electric arc plasma satisfies the local thermodynamic equilibrium condition, the electric arc flow in the arc-extinguishing chamber is in a turbulent state, the fluid motion is random, and the pressure and velocity move irregularly with time and space; the simulation does not consider the erosion effect of the electric arc on the metal contacts and the vessel wall, the temperature boundary is set as the contact surface between the anode and cathode contacts and the fluid, a one-dimensional heat conduction equation is adopted, and the highest temperature at the boundary is lower than the evaporation temperature of the vessel wall; the pressure boundary is the outlet of the arc-extinguishing chamber; the electromagnetic boundary is set as the current inflow and outflow ends, and the magnetic field is solved using the magnetic vector potential method, and the corresponding magnetic field boundary conditions are set on the symmetry plane; the turbulence model adopts the standard k-epsilon model, and the radiation process adopts the simplified T4 model; The sheath correction module (4) specifically includes: performing simulation calculations based on the original sheath voltage drop model and comparing the results with experimental results; during the arc extinction stage, the arc current drops below 100 amperes, the arc temperature decays rapidly, the sheath non-equilibrium effect is significant, and the arc voltage rises rapidly; increasing the sheath voltage drop value before the current crosses zero to correct the sheath curve, the increase in sheath voltage drop is calculated based on experimental data; widening the hump region of the sheath voltage drop model curve to obtain the corrected sheath voltage drop model.

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