Simulation analysis method for fluid in SF6 circuit breaker arc extinguish chamber by introducing electromagnetic thermal influence

Abstract

The invention relates to a simulation analysis method for fluid in an SF6 circuit breaker arc extinguish chamber by introducing electromagnetic thermal influence, and relates to the technical field of simulation analysis for fluid in the circuit breaker arc extinguish chamber. The method comprises the following steps: acquiring a target physical quantity; the target physical quantity is a physical quantity directly related to a control equation of the fluid region; the target physical quantity comprises a Joule calorific value of the high-voltage current and a Lorentz force value generated by the current changing along with time; constructing a fluid simulation model in the arc extinguish chamber according to the target physical quantity; solving the simulation model of the fluid in the arc extinguish chamber based on a real parameter fitting interpolation mode to obtain a simulation analysis result corresponding to the simulation model of the fluid in the arc extinguish chamber; the simulation analysis result is used for evaluating the performance of the SF6 circuit breaker. By adopting the method, the modeling efficiency and the simulation effect can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of fluid simulation analysis in a circuit breaker arc extinguishing chamber, and in particular to a method for fluid simulation analysis in a SF6 circuit breaker arc extinguishing chamber by introducing electromagnetic thermal influences. Background Art

[0002] In the power system, high-voltage switches are key equipment for the safe and stable operation of the power grid. The performance of high-voltage switches directly affects the reliability, economy and safety of the power system. With the rapid development of the power industry, the requirements for high-voltage switchgear are increasing day by day, especially in the field of ultra-high voltage and ultra-high voltage transmission. The breaking capacity, stability and life of switchgear have become technical problems that need to be solved urgently. When performing the breaking operation, the high-voltage switch involves complex physical processes, including transient changes in the system near-zone circuit, the generation and extinction of the switch arc, the dynamic response of the transmission mechanism and the electromagnetic effect of the drive mechanism. The interaction and influence between these multiple physical fields constitute the core challenge of high-voltage switch design and evaluation. Among them, the plasma simulation in the arc extinguishing chamber of the SF6 circuit breaker involves electromagnetic and thermal influences, and the physical parameters of SF6 gas have highly nonlinear characteristics, which is the key and most difficult part of the high-voltage switch simulation process.

[0003] Obtaining complete SF6 arc plasma physical parameters is a necessary prerequisite and basis for arc simulation. Existing technologies usually use equilibrium component calculation methods based on the principle of minimum Gibbs free energy of the system to obtain the equilibrium chemical composition and basic thermophysical parameters of SF6. This method assumes many conditions and is not suitable for areas with large temperature gradients or low electron density; it also has a large amount of calculations, which is particularly time-consuming in multi-physical field coupling calculations; at the same time, its calculation method is complex and is not suitable for large-scale promotion and application in the engineering field.

[0004] It can be seen that the current fluid simulation method for SF6 circuit breakers has the problems of low modeling efficiency and poor simulation effect. Summary of the invention

[0005] Based on this, it is necessary to provide a method, device, computer equipment, computer-readable storage medium and computer program product for fluid simulation analysis in the arc extinguishing chamber of an SF6 circuit breaker by introducing electromagnetic thermal influences, which can improve modeling efficiency and simulation effect in response to the above technical problems.

[0006] In a first aspect, an embodiment of the present application provides a method for simulating and analyzing fluid in an arc extinguishing chamber of an SF6 circuit breaker by introducing electromagnetic thermal influences. The method comprises:

[0007] Obtaining a target physical quantity; the target physical quantity is a physical quantity directly related to a control equation of a fluid region; the target physical quantity includes a Joule heat value of a high voltage current and a Lorentz force value generated by a current that varies with time;

[0008] A fluid simulation model in the arc extinguishing chamber is constructed according to the target physical quantity; the fluid simulation model in the arc extinguishing chamber is used to characterize the change of the arc magnetic fluid in the SF6 circuit breaker during the high-voltage switch breaking process;

[0009] The fluid simulation model in the arc extinguishing chamber is solved based on the real parameter fitting interpolation method to obtain the simulation analysis results corresponding to the fluid simulation model in the arc extinguishing chamber; the simulation analysis results are used to evaluate the performance of the SF6 circuit breaker.

[0010] In one embodiment, constructing a simulation model of the fluid in the arc extinguishing chamber according to the target physical quantity includes:

[0011] Determine the fluid energy conservation equation according to the Joule heat value of the high voltage current and the radiation heat value brought by the high temperature;

[0012] determining a momentum conservation equation based on the value of the Lorentz force generated by the current that varies with time;

[0013] Determine the control equation of the fluid region corresponding to the fluid simulation model in the arc extinguishing chamber according to the fluid energy conservation equation and the momentum conservation equation;

[0014] The radiation heat value brought by the high temperature is determined according to the net radiation coefficient.

[0015] In one embodiment, the method further comprises:

[0016] Obtain the magnetic field force and electric field force values ​​that charged particles experience in the magnetic field;

[0017] The magnetic field force value and the electric field force value exerted on the charged particle in the magnetic field are weightedly summed to obtain the Lorentz force value generated by the current that varies with time.

[0018] In one embodiment, the method further comprises:

[0019] Obtain current density, conductivity and potential values;

[0020] Based on the calculation rules of Joule heat and current density, the Joule heat value of the high voltage current is determined according to the current density value, the conductivity value and the potential value;

[0021] The calculation rule of the Joule heat and the current density is that the Joule heat is proportional to the square of the current density.

[0022] In one embodiment, solving the simulation model of the fluid in the arc extinguishing chamber based on real parameter fitting interpolation includes:

[0023] Obtaining a pre-built built-in physical property parameter library; the built-in physical property parameter library includes thermophysical parameter values ​​corresponding to different temperature values ​​and pressure values;

[0024] Based on the built-in physical property parameter library, matching and obtaining the value of the thermophysical parameter corresponding to the current temperature value and the pressure value;

[0025] Solving the fluid simulation model in the arc extinguishing chamber according to the values ​​of the thermophysical parameters corresponding to the current temperature value and the pressure value obtained by matching;

[0026] Among them, the thermophysical parameters are nonlinear parameters, and the thermophysical parameters include gas density, specific heat capacity at constant pressure, dynamic viscosity coefficient, thermal conductivity, and electrical conductivity corresponding to the SF6 circuit breaker.

[0027] In one of the embodiments, the governing equations of the fluid region also include a continuity equation and an energy equation of the solid domain;

[0028] The continuity equation is determined according to the fluid density and fluid velocity, and the energy equation of the solid domain is determined without considering the heat source term.

[0029] In a second aspect, the present application also provides a device for simulating and analyzing fluid in an arc extinguishing chamber of an SF6 circuit breaker by introducing electromagnetic thermal influence. The device comprises:

[0030] A target physical quantity acquisition module is used to acquire a target physical quantity; the target physical quantity is a physical quantity directly related to the control equation of the fluid region; the target physical quantity includes the Joule heat value of the high-voltage current and the Lorentz force value generated by the current that changes with time;

[0031] A model building module is used to construct a fluid simulation model in the arc extinguishing chamber according to the target physical quantity; the fluid simulation model in the arc extinguishing chamber is used to characterize the change of the arc magnetic fluid in the SF6 circuit breaker during the high-voltage switch breaking process;

[0032] The model solving module is used to solve the fluid simulation model in the arc extinguishing chamber based on the real parameter fitting interpolation method to obtain the simulation analysis results corresponding to the fluid simulation model in the arc extinguishing chamber; the simulation analysis results are used to evaluate the performance of the SF6 circuit breaker.

[0033] In a third aspect, the present application further provides a computer device. The computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0034] Obtaining a target physical quantity; the target physical quantity is a physical quantity directly related to a control equation of a fluid region; the target physical quantity includes a Joule heat value of a high voltage current and a Lorentz force value generated by a current that varies with time;

[0035] A fluid simulation model in the arc extinguishing chamber is constructed according to the target physical quantity; the fluid simulation model in the arc extinguishing chamber is used to characterize the change of the arc magnetic fluid in the SF6 circuit breaker during the high-voltage switch breaking process;

[0036] The fluid simulation model in the arc extinguishing chamber is solved based on the real parameter fitting interpolation method to obtain the simulation analysis results corresponding to the fluid simulation model in the arc extinguishing chamber; the simulation analysis results are used to evaluate the performance of the SF6 circuit breaker.

[0037] In a fourth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0038] Obtaining a target physical quantity; the target physical quantity is a physical quantity directly related to a control equation of a fluid region; the target physical quantity includes a Joule heat value of a high voltage current and a Lorentz force value generated by a current that varies with time;

[0039] A fluid simulation model in the arc extinguishing chamber is constructed according to the target physical quantity; the fluid simulation model in the arc extinguishing chamber is used to characterize the change of the arc magnetic fluid in the SF6 circuit breaker during the high-voltage switch breaking process;

[0040] The fluid simulation model in the arc extinguishing chamber is solved based on the real parameter fitting interpolation method to obtain the simulation analysis results corresponding to the fluid simulation model in the arc extinguishing chamber; the simulation analysis results are used to evaluate the performance of the SF6 circuit breaker.

[0041] In a fifth aspect, the present application further provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0042] Obtaining a target physical quantity; the target physical quantity is a physical quantity directly related to a control equation of a fluid region; the target physical quantity includes a Joule heat value of a high voltage current and a Lorentz force value generated by a current that varies with time;

[0043] A fluid simulation model in the arc extinguishing chamber is constructed according to the target physical quantity; the fluid simulation model in the arc extinguishing chamber is used to characterize the change of the arc magnetic fluid in the SF6 circuit breaker during the high-voltage switch breaking process;

[0044] The fluid simulation model in the arc extinguishing chamber is solved based on the real parameter fitting interpolation method to obtain the simulation analysis results corresponding to the fluid simulation model in the arc extinguishing chamber; the simulation analysis results are used to evaluate the performance of the SF6 circuit breaker.

[0045] The above-mentioned fluid simulation analysis method, device, computer equipment, storage medium and computer program product for SF6 circuit breaker arc extinguishing chamber with electromagnetic thermal influence are used to analyze the fluid simulation in the arc extinguishing chamber of the SF6 circuit breaker by introducing electromagnetic thermal influence; firstly, the target physical quantities related to the fluid area control equations are obtained, including the Joule heat value of the high-voltage current and the Lorentz force value that varies with time, which directly affect the thermodynamic behavior of the fluid; then, a fluid simulation model of the arc extinguishing chamber is constructed based on these target physical quantities, and the model reflects the control equations of the fluid area, such as the continuity equation, the momentum conservation equation, and the momentum conservation equation. The simulation results of the fluid in the arc extinguishing chamber are obtained by fitting and interpolating the real parameters to solve the model, so as to evaluate the performance of the SF6 circuit breaker during the high-voltage switch breaking process, and then optimize the circuit breaker design. The basic solution in electromagnetic theory is not introduced, and only the influence of electromagnetic force and thermal characteristics on fluid characteristics is considered, which effectively simplifies the plasma simulation calculation. At the same time, the real parameter fitting and interpolation method is used to simplify the calculation process of SF6 physical parameters, which greatly simplifies the calculation process, improves the construction and calculation efficiency of the model, and improves the effect of simulation analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] FIG1 is an application environment diagram of a method for simulating and analyzing fluid in an arc extinguishing chamber of a SF6 circuit breaker in which electromagnetic thermal influence is introduced in one embodiment;

[0048] Figure 2 A schematic diagram of a flow chart of a method for simulating and analyzing fluid in an arc extinguishing chamber of an SF6 circuit breaker in which electromagnetic thermal influence is introduced in an embodiment;

[0049] Figure 3 It is a flow chart of a method for simulating and analyzing fluid in an arc extinguishing chamber of an SF6 circuit breaker in another embodiment of the present invention, which introduces electromagnetic thermal influence;

[0050] Figure 4 It is a structural block diagram of a fluid simulation and analysis device for an SF6 circuit breaker arc extinguishing chamber that introduces electromagnetic thermal influence in one embodiment;

[0051] FIG. 5 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0053] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards of relevant countries and regions.

[0054] The fluid simulation analysis method for the arc extinguishing chamber of an SF6 circuit breaker with electromagnetic thermal effects provided in the embodiment of the present application can be applied in the application environment shown in Figure 1. The terminal 102 communicates with the server 104 through a network.

[0055] The terminal 102 may be, but is not limited to, various personal computers, laptops, smart phones, tablet computers, IoT devices, and portable wearable devices. The IoT devices may be smart speakers, smart TVs, smart air conditioners, smart car-mounted devices, etc. The portable wearable devices may be smart watches, smart bracelets, head-mounted devices, etc. The server 104 may be implemented as an independent server or a server cluster consisting of multiple servers.

[0056] In one embodiment, Figure 2 As shown, a method for simulating and analyzing the fluid in the arc extinguishing chamber of an SF6 circuit breaker by introducing electromagnetic thermal influence is provided. The method is applied to the terminal 102 in FIG. 1 as an example for explanation, and includes the following steps:

[0057] S201, obtaining a target physical quantity.

[0058] The target physical quantity is a physical quantity directly related to the control equation of the fluid region; the target physical quantity includes the Joule heat value of the high-voltage current and the Lorentz force value generated by the current that changes with time.

[0059] S202, constructing a simulation model of the fluid in the arc extinguishing chamber according to the target physical quantity.

[0060] Among them, the fluid simulation model in the arc extinguishing chamber is used to characterize the changes in the arc magnetic fluid of the SF6 circuit breaker during the high-voltage switch breaking process.

[0061] Exemplarily, the fluid simulation model in the arc extinguishing chamber can be embodied by the control equations of the fluid region and the form of their solutions. Specifically, the control equations of the fluid region may include: continuity equation, momentum conservation equation, fluid energy conservation equation, energy equation of the solid domain, etc.

[0062] S203, solving the simulation model of the fluid in the arc extinguishing chamber based on the real parameter fitting interpolation method, and obtaining the simulation analysis result corresponding to the simulation model of the fluid in the arc extinguishing chamber.

[0063] Among them, the simulation analysis results are used to evaluate the performance of SF6 circuit breakers.

[0064] For example, considering that only Joule heat and Lorentz force directly enter the fluid control equation, these two physical quantities are not coupled with the NS equation of the fluid for solution, but are treated as external input items and source items. These two items are calculated externally by dedicated electromagnetic analysis software and given by the general coupling control platform.

[0065] In the above-mentioned simulation and analysis method of fluid in the arc extinguishing chamber of SF6 circuit breaker with the introduction of electromagnetic thermal influence, the fluid simulation in the arc extinguishing chamber of SF6 circuit breaker is analyzed by introducing electromagnetic thermal influence; firstly, the target physical quantities related to the fluid region control equations are obtained, including the Joule heat value of the high-voltage current and the Lorentz force value that varies with time, which directly affect the thermodynamic behavior of the fluid; then, based on these target physical quantities, a fluid simulation model of the arc extinguishing chamber is constructed, and the model reflects the control equations of the fluid region, such as the continuity equation, the momentum conservation equation, the fluid energy conservation equation and the solid domain energy equation; finally, the model is solved by the real parameter fitting interpolation method to obtain the simulation analysis results of the fluid in the arc extinguishing chamber, so as to evaluate the performance of the SF6 circuit breaker during the high-voltage switch breaking process, and then optimize the circuit breaker design, without introducing the basic solution in the electromagnetic theory, only considering the influence of the electromagnetic thermal characteristics on the fluid characteristics, and effectively simplifying the plasma simulation calculation; at the same time, the real parameter fitting interpolation method is adopted to simplify the calculation process of the SF6 physical property parameters, greatly simplify the calculation process, improve the model construction and calculation efficiency, and improve the effect of simulation analysis.

[0066] In one embodiment, a fluid simulation model of the arc extinguishing chamber is constructed according to the target physical quantity, including: determining the fluid energy conservation equation according to the Joule heat value of the high-voltage current and the radiation heat value brought by the high temperature; determining the momentum conservation equation according to the Lorentz force value generated by the current that changes with time; determining the control equation of the fluid area corresponding to the fluid simulation model in the arc extinguishing chamber according to the fluid energy conservation equation and the momentum conservation equation; wherein the radiation heat value brought by the high temperature is determined according to the net radiation coefficient.

[0067] For example, the fluid energy conservation equation:

[0068]

[0069] In the formula, h is the specific enthalpy, K is the kinetic energy, αeff is the effective thermal diffusion coefficient, εN is the net radiation coefficient, and Qjoule is the Joule heat source term. The Joule heat value of high voltage current is The radiation heat value brought by high temperature is .

[0070] Momentum conservation equation:

[0071]

[0072] Where p is pressure, FB is Lorentz force, and τ is turbulent stress. The Lorentz force generated by the current is .

[0073] In this embodiment, firstly, the fluid energy conservation equation is determined according to the Joule heating value of the high-voltage current and the radiation heating value brought by the high temperature; secondly, the momentum conservation equation is determined according to the Lorentz force value generated by the current that changes with time, considering the effects of pressure, Lorentz force and turbulent stress; the fluid energy conservation equation and the momentum conservation equation are combined to finally form the control equation of the fluid in the arc extinguishing chamber; by accurately simulating the interaction between the arc and the fluid, the arc extinguishing performance of the SF6 circuit breaker can be effectively evaluated, thereby optimizing the design, improving the safety and reliability of the equipment, and ensuring the stable operation of the high-voltage switch in practical applications. The basic solution in electromagnetic theory is not introduced, and only the influence of electromagnetic force and thermal characteristics on fluid characteristics is considered, which effectively simplifies the plasma simulation calculation and improves the calculation efficiency.

[0074] In one embodiment, the method further includes: obtaining the magnetic field force and electric field force values ​​exerted on the charged particles in the magnetic field; performing weighted summation on the magnetic field force and electric field force values ​​exerted on the charged particles in the magnetic field to obtain the Lorentz force value generated by the current that changes with time.

[0075] For example, the Lorentz force is the sum of the magnetic field force and the electric field force exerted on a charged particle in a magnetic field, and is calculated using the following formula:

[0076]

[0077] Where q is the charge, E is the electric field intensity, J is the current density, and B is the magnetic induction intensity.

[0078] In this embodiment, the magnetic field force and electric field force values ​​exerted on the charged particles in the magnetic field are first obtained. Specifically, the magnetic field force is determined by the motion state of the charged particles in the magnetic field, while the electric field force is determined by the electric field strength and the charge of the particles. Then, the time-varying Lorentz force value is calculated by weighted summing these two forces. The Lorentz force value is accurately calculated to prepare for subsequent simulations, so that the fluid simulation model can more accurately simulate the dynamic changes of the fluid under the interaction between the current and the magnetic field, thereby improving the performance evaluation and design optimization of the arc extinguishing chamber, and ensuring the reliability and safety of the high-voltage switch under complex arc conditions.

[0079] In one embodiment, the method further includes: obtaining current density value, conductivity value and potential value; determining the Joule heat value of the high voltage current based on the current density value, conductivity value and potential value based on the calculation rules of Joule heat and current density.

[0080] Among them, the calculation rule of Joule heat and current density is that Joule heat is proportional to the square of current density.

[0081] For example, Joule heating is proportional to the square of the current density:

[0082]

[0083] Where σ is the conductivity and φ is the electric potential.

[0084] In this embodiment, the current density value, the conductivity value and the potential value are first obtained, and based on the calculation rule that the Joule heat is proportional to the square of the current density, the obtained current density, conductivity and potential are combined to calculate the Joule heat value of the high-voltage current; by accurately quantifying the Joule heat of the high-voltage current, key data support is provided, and the influence of current density on energy conversion is considered in the fluid simulation model, thereby facilitating subsequent simulation analysis.

[0085] In one embodiment, the fluid simulation model in the arc extinguishing chamber is solved based on the real parameter fitting interpolation method, including: obtaining a pre-built built-in physical property parameter library; matching the values ​​of the thermophysical parameters corresponding to the current temperature values ​​and pressure values ​​based on the built-in physical property parameter library; solving the fluid simulation model in the arc extinguishing chamber according to the matched values ​​of the thermophysical parameters corresponding to the current temperature values ​​and pressure values.

[0086] Among them, the thermophysical parameters are nonlinear parameters, and the thermophysical parameters include gas density, specific heat capacity at constant pressure, dynamic viscosity coefficient, thermal conductivity, and electrical conductivity corresponding to the SF6 circuit breaker.

[0087] The built-in physical property parameter library includes thermophysical parameter values ​​corresponding to different temperature values ​​and pressure values.

[0088] For example, the arc extinguishing chamber is filled with SF6 gas, and its plasma thermophysical parameters show a nonlinear change trend with temperature. In order to ensure the accuracy of the calculation, nonlinear thermophysical parameters need to be set in the model. Assuming that the energy relaxation process of each particle in the equilibrium SF6 plasma has been completed, the temperature of electrons and heavy ions is the same, and its thermophysical parameters are functions of temperature and pressure. In the solution, a built-in physical property parameter library can be implanted in advance for the real gas changes of SF6; it also supports users to give the changes of physical property parameters with temperature and pressure in the form of external import.

[0089] The calculation process will automatically call the physical parameter library given by the user, and automatically update the parameters during the solution process without the need for additional settings by the user. The preset physical parameters will be loaded when the simulation is initialized. In each iteration of each time step in the calculation, after solving the pressure equation and energy equation, the physical parameters of SF6 will be updated according to the current pressure and temperature of each fluid unit. At the same time, the conductivity distribution at this time is calculated and passed to the electromagnetic field through the coupling platform for electromagnetic calculation. This iterative cycle is repeated until the final calculation is completed.

[0090] In this embodiment, the system first obtains a built-in physical property parameter library, which contains thermophysical parameter values ​​under different temperature and pressure conditions, and then matches the corresponding nonlinear thermophysical parameters according to the current temperature and pressure; by accurately simulating the nonlinear thermophysical properties of SF6 gas, the calculation accuracy and real-time performance of the fluid simulation model in the arc extinguishing chamber are significantly improved, and the calculation process of SF6 physical property parameters is simplified by using real parameter fitting interpolation, which greatly simplifies the calculation process and improves the calculation efficiency.

[0091] In one embodiment, the control equations of the fluid region also include a continuity equation and an energy equation of the solid domain; wherein the continuity equation is determined according to the fluid density and the fluid velocity, and the energy equation of the solid domain is determined without considering the heat source term.

[0092] Exemplarily, the continuity equation:

[0093]

[0094] Where ρ is the fluid density, t is the time, and U is the fluid velocity vector.

[0095] The solid domain does not involve changes in flow-related physical quantities, and when the heat source term is not considered, its energy equation is as follows:

[0096]

[0097] In another embodiment, Figure 3 As shown, a method for simulating and analyzing the fluid in the arc extinguishing chamber of an SF6 circuit breaker by introducing electromagnetic thermal influence is provided, comprising the following steps:

[0098] S301, obtaining the magnetic field force value and electric field force value exerted on the charged particle in the magnetic field;

[0099] S302, performing weighted summation of the magnetic field force and the electric field force exerted on the charged particle in the magnetic field to obtain the Lorentz force value generated by the current that varies with time;

[0100] S303, obtaining a current density value, a conductivity value, and an electric potential value;

[0101] S304, determining the Joule heat value of the high voltage current based on the calculation rules of Joule heat and current density according to the current density value, the conductivity value and the potential value;

[0102] S305, determining the fluid energy conservation equation according to the Joule heat value of the high voltage current and the radiation heat value brought by the high temperature;

[0103] S306, determining a momentum conservation equation according to a Lorentz force value generated by the current that varies with time;

[0104] S307, determining a control equation of a fluid region corresponding to the fluid simulation model in the arc extinguishing chamber according to the fluid energy conservation equation and momentum conservation equation;

[0105] S308, solving the simulation model of the fluid in the arc extinguishing chamber based on the real parameter fitting interpolation method, and obtaining the simulation analysis result corresponding to the simulation model of the fluid in the arc extinguishing chamber.

[0106] It should be noted that the specific limitations of the above steps can be found in the specific limitations of the above-mentioned method for simulating and analyzing the fluid in the arc extinguishing chamber of an SF6 circuit breaker by introducing electromagnetic thermal influences, which will not be repeated here.

[0107] In the prior art, there are complex and mutually coupled electrical, thermal, and mechanical physical processes in the arc extinguishing chamber of the SF6 circuit breaker during the current breaking process. How to deal with the mutual influence between the physical processes and the changes of various physical parameters in this process is the primary issue that needs to be considered in the process of plasma simulation calculation in the arc extinguishing chamber.

[0108] Existing simulation technology is usually based on Ansys Fluent software (software for computational fluid dynamics) combined with UDF (User Defined Function). This method requires users to solve the electric and magnetic fields through the UDS function on the basis of basic electromagnetic theory, and define the material thermal physical parameters through UDF. The learning curve is steep and difficult to use. At the same time, due to the fixed calculation process of Fluent, users cannot control the solution process, and the disadvantages are prominent in the debugging process of complex cases. At the same time, this method means that the same set of grids are used for fluid analysis and electromagnetic calculations. Since the control equations in electromagnetic theory and the NS equations (Navier-Stokes equations) in fluids are inconsistent in form and properties, the use of the same set of grids will greatly limit the flexibility of each other, which is not conducive to calculation accuracy and convergence. In addition, this method requires the calculation before and after the arc is started to be realized in stages through the restart function. The process is relatively cumbersome and not suitable for large-scale promotion and application.

[0109] In view of the above shortcomings, the embodiment of the present application provides a method for simulating and analyzing the fluid in the arc extinguishing chamber of an SF6 circuit breaker by introducing electromagnetic thermal effects, also known as a method for simulating and analyzing the fluid in the arc extinguishing chamber of an SF6 circuit breaker by introducing electromagnetic thermal effects in fluid calculation. This method does not solve basic parameters in electromagnetic theory such as electric field intensity and magnetic vector when performing fluid calculations, but only introduces physical quantities directly related to the fluid control equations such as Joule heat and Lorentz force. Based on this idea, a special simulation software for arc magnetic fluid is developed, and the changes in the thermal properties of plasma are processed internally by interpolation, avoiding the large amount of calculations caused by the use of local thermodynamic equilibrium assumptions, improving the convergence characteristics of fluid calculations, and improving simulation efficiency.

[0110] The following is a detailed description of a method for simulating and analyzing the fluid in the arc extinguishing chamber of an SF6 circuit breaker by introducing electromagnetic thermal effects using a specific embodiment. It is worth noting that the following description is only an exemplary description and is not a specific limitation to the application.

[0111] The method for simulating and analyzing the fluid in the arc extinguishing chamber of an SF6 circuit breaker with the introduction of electromagnetic thermal influence provided in the present application specifically includes the following contents:

[0112] Since there are complex multi-physics problems such as air flow field, temperature field, electromagnetic field, etc. in the arc extinguishing chamber, the influence of electromagnetic thermal force must be considered in the analysis. During the interruption process of SF6 circuit breaker, the electromagnetic thermal characteristics of the fluid in the arc extinguishing chamber mainly affect the plasma flow characteristics in two aspects:

[0113] First, the influence of Joule heat and Lorentz force generated by the electromagnetic properties of the fluid on the fluid velocity, pressure, temperature, etc.; second, the influence of local temperature, pressure and other parameters on the plasma physical properties during the calculation process.

[0114] The arc magnetic fluid simulation during the high-voltage switch breaking process can be divided into two stages from the perspective of the physical process, namely the cold air flow simulation stage and the arc magnetic fluid simulation stage after arcing.

[0115] In the simulation, the cold air flow simulation mainly considers the changes in flow parameters and flow conditions caused by contact movement, and does not consider changes in electromagnetic related properties. Therefore, the simulation can be completed within the scope of the single physical field of the fluid at this stage, without the need for coupling with the electromagnetic field and circuit. Since the flow conditions are relatively simple, laminar flow is used by default for simulation at this stage to improve calculation efficiency.

[0116] Arcing occurs when the moving and static contacts of the circuit breaker are separated. In this process, the SF6 arc is fully ionized into an equilibrium plasma, and the changes in physical parameters such as the electric field, temperature field, and flow field in the arc extinguishing chamber affect each other, with a high degree of coupling. At the control equation level, the fluid energy equation needs to consider the Joule heat and radiation heat of the high-voltage current, and the momentum equation needs to consider the Lorentz force generated by the current that changes with time. At this time, the control equation of the fluid region is as follows:

[0117] Continuity equation:

[0118]

[0119] Where ρ is the fluid density, t is the time, and U is the fluid velocity vector.

[0120] Momentum conservation equation:

[0121]

[0122] Where p is pressure, FB is Lorentz force, and τ is turbulent stress.

[0123]

[0124] Where μ is the fluid viscosity and I is the unit tensor.

[0125] Fluid energy conservation equation:

[0126]

[0127] In the formula, h is the specific enthalpy, K is the kinetic energy, and αeff is the effective thermal diffusion coefficient. εN is the net radiation coefficient, and Qjoule is the Joule heat source term. The rightmost term on the right side of the momentum equation is the Lorentz force source term generated by the magnetic field generated by the current changing with time on the fluid. The last two terms in the energy equation are the radiation heat brought by high temperature and the Joule heat caused by the introduction of high voltage current. The radiation heat source term is calculated from the net radiation coefficient.

[0128] The solid domain does not involve changes in flow-related physical quantities, and when the heat source term is not considered, its energy equation is as follows:

[0129]

[0130] In this application, the "introduction of electromagnetic thermal influence" is mainly reflected in the Lorentz force term and Joule heat term in the momentum equation. Both of these terms are related to the electromagnetic properties of the fluid. The Lorentz force is the sum of the magnetic field force and the electric field force on the charged particle in the magnetic field, and is calculated using the following formula:

[0131]

[0132] Where q is the charge, E is the electric field intensity, J is the current density, and B is the magnetic induction intensity.

[0133] Joule heating is proportional to the square of the current density:

[0134]

[0135] Where σ is the conductivity and φ is the electric potential.

[0136] In previous studies, the electric field intensity E and the current density J were solved in the fluid, and then the Lorentz force and Joule heat were calculated. In fact, these basic electromagnetic parameters do not directly participate in the coupled iteration of pressure-velocity-energy of the fluid. In this application, considering that only two physical quantities, Joule heat and Lorentz force, directly enter the fluid control equation, these two physical quantities are not coupled and solved with the NS equations of the fluid, but the item is treated as an external input item and treated as a source item. These two items are calculated externally by dedicated electromagnetic analysis software and given by the general coupling control platform. At the same time, the conductivity of the plasma to be output in the fluid calculation is used as an input item for external electromagnetic calculations.

[0137] By adopting this method, it is no longer necessary to solve the basic electromagnetic parameters in the plasma solution process. Only the influence of electromagnetic thermal characteristics on fluid characteristics is considered, which can effectively simplify the plasma simulation calculation. At the same time, since the electromagnetic and fluid are not solved in the same set of grids, the electromagnetic simulation can adopt a more free grid control strategy and iterative control strategy, which is conducive to obtaining more accurate Lorentz force and Joule heat. At the same time, in the previous simulation of plasma in the arc extinguishing chamber, since the electromagnetic parameters and fluid parameters are solved together, it is inconvenient to adjust the convergence control of each other and it is easy to cause divergence. The fluid simulation analysis method for the arc extinguishing chamber of the SF6 circuit breaker that introduces the influence of electromagnetic thermal force provided in the present application has a higher degree of control freedom because the fluid and electromagnetic control equations are solved separately, which is conducive to the final convergence of the calculation results.

[0138] The density of SF6 changes with increasing temperature and pressure. The increased thermal motion of gas molecules under the action of an arc may result in a decrease in density. An increase in temperature usually results in an increase in gas viscosity because the frequency of collisions between molecules increases. However, an increase in pressure may result in a decrease in viscosity because the interactions between molecules increase. Thermal conductivity is a measure of the ability of a material to conduct heat. Under arc conditions, the thermal conductivity of SF6 may increase due to the increased thermal motion of the molecules. Specific heat is the amount of heat required to raise the temperature of a substance per unit mass. Under high temperature conditions, the specific heat of SF6 may increase due to the excitation of internal energy levels of the molecules. The presence of an arc causes the gas to ionize, resulting in a significant increase in conductivity. This is because the free electrons and ions produced by ionization can conduct an electric current.

[0139] Although the physical parameters of real SF6 gas are highly nonlinear and have many influencing factors, since the gas simulated in this scenario is fixed to SF6, if the traditional equilibrium component calculation method is used, a series of unnecessary repeated calculations will be performed during repeated simulations. The arc extinguishing chamber is filled with SF6 gas, and its plasma thermophysical parameters show a nonlinear change trend with temperature. In order to ensure the accuracy of the calculation, nonlinear thermophysical parameters such as SF6 gas density, specific heat capacity at constant pressure, dynamic viscosity coefficient, thermal conductivity, and electrical conductivity need to be set in the model. Assuming that the energy relaxation process of each particle in the equilibrium SF6 plasma has been completed, the temperature of electrons and heavy ions is the same, and its thermophysical parameters are functions of temperature and pressure. In the solution, a built-in physical parameter library can be implanted in advance for the changes in real SF6 gas. In addition, in order to expand the usage scenarios, it also supports users to give the changes in physical parameters with temperature and pressure in the form of external import. The calculation process will automatically call the physical parameter library given by the user, and automatically update the parameters during the solution process without the need for additional settings by the user. The preset physical parameters will be loaded when the simulation is initialized. In each iteration of each time step in the calculation, after solving the pressure equation and energy equation, the physical parameters of SF6 are updated according to the current pressure and temperature of each fluid unit, including density, viscosity, thermal conductivity, specific heat and electrical conductivity. At the same time, the electrical conductivity distribution is calculated and passed to the electromagnetic field through the coupling platform for electromagnetic calculation. This iterative cycle is repeated until the final calculation is completed.

[0140] The fluid simulation analysis method for the arc extinguishing chamber of the SF6 circuit breaker provided in this application introduces electromagnetic thermal effects and strives to avoid solving the complex Maxwell equations, does not introduce the basic solution in electromagnetic theory, and only considers the influence of electromagnetic thermal characteristics on fluid characteristics, effectively simplifying the plasma simulation calculation. At the same time, the real parameter fitting interpolation method is used to simplify the calculation process of SF6 physical parameters, greatly simplify the calculation process, and improve the calculation efficiency.

[0141] In the simulation of plasma in the arc extinguishing chamber of the SF6 circuit breaker start-up process, there are many plasma characteristic parameters in the arc extinguishing chamber, which are dependent and interact with each other. The present invention strives to make the fluid solution process clear and concise while considering the influence of electromagnetic thermal force. The advantages of using the fluid simulation analysis method for the arc extinguishing chamber of the SF6 circuit breaker introduced with electromagnetic thermal force provided by the present application are:

[0142] (1) No redundant electromagnetic parameters are introduced in the fluid calculation. Only Joule heat and Lorentz force directly related to the fluid calculation are introduced. This can effectively simplify the plasma simulation calculation, facilitate the final calculation convergence, and improve the calculation accuracy.

[0143] (2) The changes in the thermophysical properties of plasma are processed by interpolation, which avoids the large amount of calculation caused by the local thermodynamic equilibrium assumption, improves the convergence characteristics of fluid calculations, and improves simulation efficiency.

[0144] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0145] Based on the same inventive concept, the embodiment of the present application also provides a device for simulating and analyzing fluid in the arc extinguishing chamber of an SF6 circuit breaker with electromagnetic thermal influences, which is used to implement the method for simulating and analyzing fluid in the arc extinguishing chamber of an SF6 circuit breaker with electromagnetic thermal influences. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of one or more devices for simulating and analyzing fluid in the arc extinguishing chamber of an SF6 circuit breaker with electromagnetic thermal influences provided below can be referred to the limitations of the method for simulating and analyzing fluid in the arc extinguishing chamber of an SF6 circuit breaker with electromagnetic thermal influences in the above text, and will not be repeated here.

[0146] In one embodiment, Figure 4 As shown, a fluid simulation and analysis device for an SF6 circuit breaker arc extinguishing chamber introducing electromagnetic thermal influence is provided, comprising: a target physical quantity acquisition module 401, a model construction module 402, and a model solution module 403, wherein:

[0147] The target physical quantity acquisition module 401 is used to acquire the target physical quantity; the target physical quantity is a physical quantity directly related to the control equation of the fluid region; the target physical quantity includes the Joule heat value of the high voltage current and the Lorentz force value generated by the current that changes with time;

[0148] The model building module 402 is used to build a simulation model of the fluid in the arc extinguishing chamber according to the target physical quantity; the simulation model of the fluid in the arc extinguishing chamber is used to characterize the change of the arc magnetic fluid in the SF6 circuit breaker during the high-voltage switch breaking process;

[0149] The model solving module 403 is used to solve the simulation model of the fluid in the arc extinguishing chamber based on the real parameter fitting interpolation method to obtain the simulation analysis results corresponding to the simulation model of the fluid in the arc extinguishing chamber; the simulation analysis results are used to evaluate the performance of the SF6 circuit breaker.

[0150] In one embodiment, the device is used to: determine the fluid energy conservation equation based on the Joule heating value of the high-voltage current and the radiation heating value brought by the high temperature; determine the momentum conservation equation based on the Lorentz force value generated by the current that changes with time; determine the control equation of the fluid area corresponding to the fluid simulation model in the arc extinguishing chamber based on the fluid energy conservation equation and the momentum conservation equation.

[0151] In one embodiment, the device is used to: obtain the magnetic field force and electric field force values ​​exerted on the charged particles in the magnetic field; perform weighted summation on the magnetic field force and electric field force values ​​exerted on the charged particles in the magnetic field to obtain the Lorentz force value generated by the current that changes with time.

[0152] In one embodiment, the device is used to: obtain current density value, conductivity value and potential value; based on the calculation rules of Joule heat and current density, determine the Joule heat value of high voltage current according to the current density value, conductivity value and potential value.

[0153] In one embodiment, the device is used to: obtain a pre-built built-in physical property parameter library; the built-in physical property parameter library includes thermophysical parameter values ​​corresponding to different temperature values ​​and pressure values; based on the built-in physical property parameter library, match the values ​​of thermophysical parameters corresponding to the current temperature values ​​and pressure values; solve the fluid simulation model in the arc extinguishing chamber according to the matched values ​​of thermophysical parameters corresponding to the current temperature values ​​and pressure values.

[0154] Each module in the above-mentioned SF6 circuit breaker arc chamber fluid simulation analysis device with electromagnetic thermal influence can be fully or partially implemented by software, hardware and their combination. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0155] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be shown in FIG5. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, the memory, and the input / output interface are connected via a system bus, and the communication interface, the display unit, and the input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner may be implemented through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a fluid simulation analysis method for an SF6 circuit breaker arc extinguishing chamber is implemented that introduces electromagnetic thermal influences. The display unit of the computer device is used to form a visually visible picture, which may be a display screen, a projection device, or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0156] Those skilled in the art will understand that the structure shown in FIG. 5 is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0157] In one embodiment, a computer device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the steps in the above method embodiments are implemented.

[0158] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0159] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0160] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0161] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0162] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for simulating and analyzing the fluid in the arc extinguishing chamber of an SF6 circuit breaker by introducing electromagnetic thermal influence, characterized in that: The method comprises: Obtaining a target physical quantity; the target physical quantity is a physical quantity directly related to a control equation of a fluid region; the target physical quantity includes a Joule heat value of a high voltage current and a Lorentz force value generated by a current that varies with time; A fluid simulation model in the arc extinguishing chamber is constructed according to the target physical quantity; the fluid simulation model in the arc extinguishing chamber is used to characterize the change of the arc magnetic fluid in the SF6 circuit breaker during the high-voltage switch breaking process; The fluid simulation model in the arc extinguishing chamber is solved based on the real parameter fitting interpolation method to obtain the simulation analysis results corresponding to the fluid simulation model in the arc extinguishing chamber; the simulation analysis results are used to evaluate the performance of the SF6 circuit breaker.

2. The method according to claim 1, characterized in that The fluid simulation model in the arc extinguishing chamber is constructed according to the target physical quantity, including: Determine the fluid energy conservation equation according to the Joule heat value of the high voltage current and the radiation heat value brought by the high temperature; determining a momentum conservation equation based on the value of the Lorentz force generated by the current that varies with time; Determine the control equation of the fluid region corresponding to the fluid simulation model in the arc extinguishing chamber according to the fluid energy conservation equation and the momentum conservation equation; The radiation heat value brought by the high temperature is determined according to the net radiation coefficient.

3. The method according to claim 1, characterized in that The method further comprises: Obtain the magnetic field force and electric field force values ​​that charged particles experience in the magnetic field; The magnetic field force value and the electric field force value exerted on the charged particle in the magnetic field are weightedly summed to obtain the Lorentz force value generated by the current that varies with time.

4. The method according to claim 1, characterized in that: The method further comprises: Obtain current density, conductivity and potential values; Based on the calculation rules of Joule heat and current density, the Joule heat value of the high voltage current is determined according to the current density value, the conductivity value and the potential value; The calculation rule of the Joule heat and the current density is that the Joule heat is proportional to the square of the current density.

5. The method according to claim 1, characterized in that The method of solving the fluid simulation model in the arc extinguishing chamber based on real parameter fitting interpolation includes: Obtaining a pre-built built-in physical property parameter library; the built-in physical property parameter library includes thermophysical parameter values ​​corresponding to different temperature values ​​and pressure values; Based on the built-in physical property parameter library, matching and obtaining the value of the thermophysical parameter corresponding to the current temperature value and the pressure value; Solving the fluid simulation model in the arc extinguishing chamber according to the values ​​of the thermophysical parameters corresponding to the current temperature value and the pressure value obtained by matching; Among them, the thermophysical parameters are nonlinear parameters, and the thermophysical parameters include gas density, specific heat capacity at constant pressure, dynamic viscosity coefficient, thermal conductivity, and electrical conductivity corresponding to the SF6 circuit breaker.

6. The method according to claim 1, characterized in that The governing equations of the fluid region also include the continuity equation and the energy equation of the solid domain; The continuity equation is determined according to the fluid density and fluid velocity, and the energy equation of the solid domain is determined without considering the heat source term.

7. A fluid simulation and analysis device for an SF6 circuit breaker arc extinguishing chamber that introduces electromagnetic thermal influence, characterized in that: The device comprises: A target physical quantity acquisition module is used to acquire a target physical quantity; the target physical quantity is a physical quantity directly related to the control equation of the fluid region; the target physical quantity includes the Joule heat value of the high-voltage current and the Lorentz force value generated by the current that changes with time; A model building module is used to construct a fluid simulation model in the arc extinguishing chamber according to the target physical quantity; the fluid simulation model in the arc extinguishing chamber is used to characterize the change of the arc magnetic fluid in the SF6 circuit breaker during the high-voltage switch breaking process; The model solving module is used to solve the fluid simulation model in the arc extinguishing chamber based on the real parameter fitting interpolation method to obtain the simulation analysis results corresponding to the fluid simulation model in the arc extinguishing chamber; the simulation analysis results are used to evaluate the performance of the SF6 circuit breaker.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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