Method and device for evaluating post-arc relaxation characteristic of arc plasma

Abstract

The invention provides an arc plasma post-arc relaxation characteristic evaluation method and device, and belongs to the technical field of electrical switch equipment, the process that arc plasma is converted from a non-equilibrium state to an equilibrium state is regarded as the process that electrons and heavy particles collide for heat transfer until the temperatures of the electrons and the heavy particles are the same; describing an electron distribution function by using a kinetic equation with a collision term, and calculating an electron relaxation frequency; and calculating relaxation time of collision between electrons, relaxation time of collision between electrons and heavy particles and relaxation time of collision between heavy particles according to the energy change rate and the relationship between the energy change rate and the temperature balance time, and taking the maximum value as final relaxation time. According to the method, the prediction model is high in precision, the prediction result is accurate, meanwhile, the test amount in novel insulating gas research and development work is reduced, the research cost and the design risk are reduced, and the research and development efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical switchgear, and particularly relates to a method and device for evaluating the post-arc relaxation characteristics of arc plasma. Background Art

[0002] During the processes of switching of reactive power compensation equipment in UHV projects, closing of no-load lines, interruption at current zero-crossing, and multiple re-breakdowns caused by disconnector operations in high-voltage SF6 circuit breakers, since the current in the arc gap between contacts is relatively small, the generated arc plasma is often in a non-equilibrium state. In the post-arc stage, the temperature of the arc plasma drops rapidly. Due to the large difference in mass between electrons and heavy particles, after the particles collide with each other and exchange energy, the electron temperature in the plasma is much higher than the heavy particle temperature, and the arc plasma deviates from the equilibrium state. The study of the non-equilibrium state of the plasma is of great significance for evaluating the breaking capacity of the actual high-voltage circuit breaker during operation.

[0003] The plasma in the non-equilibrium state can reach the equilibrium state through frequent collisions between particles. This process of transition from the non-equilibrium state to the equilibrium state is called the relaxation process. In order to more accurately evaluate the time required for the plasma to transition from the non-equilibrium state to the equilibrium state - the relaxation time. Scholars have respectively adopted methods of constructing a collision model between plasma particles and through plasma chemical kinetics to study the relaxation process and collision process between particles, and studied the parameter calculation method of the plasma relaxation process. The relevant literature (Winkler R, Loffhagen D, Sigeneger F. Temporal and spatial relaxation of electrons in low temperature plasmas[J]. Applied surface science) elaborated and demonstrated the spatio-temporal variation of electron relaxation in atomic and molecular plasmas under different plasma conditions on the basis of a comprehensive and rigorous non-hydrodynamic study of electron relaxation using the kinetic method. In particular, the relaxation behavior of the electron energy distribution function, the energy and momentum dissipation related to electron collisions, and the resulting characteristic total relaxation time and relaxation length were analyzed. The literature (Xiang Jiang. Theoretical study on collision terms and transport coefficients of non-equilibrium plasmas[D].) used the kinetic method to study the collision process between particles in the plasma from a microscopic perspective, deduced the calculation formulas for the dynamic friction coefficient and dynamic diffusion coefficient in the plasma, and analyzed the relaxation parameters between particles in different distribution states.

[0004] Up to now, a series of studies have been carried out on the non-equilibrium plasma generated during the operation of high-voltage switchgear in the published literature. However, due to its great complexity, no theoretical system that can accurately guide engineering practice has been formed yet. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present application proposes a method and device for evaluating the post-arc relaxation characteristics of an arc plasma, so as to accurately predict the post-arc relaxation characteristics of the plasma.

[0006] In a first aspect, the present application proposes a method for evaluating the post-arc relaxation characteristics of an arc plasma, including:

[0007] Regarding the process of the arc plasma transitioning from a non-equilibrium state to an equilibrium state as a process of heat transfer by electron-heavy particle collisions until the electron and heavy particle temperatures are the same;

[0008] During the process of heat transfer by electron-heavy particle collisions, use the kinetic equation with a collision term to describe the distribution function of electrons and calculate the electron relaxation frequency;

[0009] Obtain data on electrons and heavy particles;

[0010] According to the data of the electrons and heavy particles, calculate the energy change rate caused by the collisions of the two types of particles and the relationship between the energy change rate and the temperature equilibrium time;

[0011] According to the energy change rate and the relationship between the energy change rate and the temperature equilibrium time, calculate the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions;

[0012] Among the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions, take the largest value as the final relaxation time;

[0013] Take the electron relaxation frequency and the final relaxation time as the post-arc relaxation characteristics of the arc plasma.

[0014] During the process of heat transfer by electron-heavy particle collisions, using the kinetic equation with a collision term to describe the distribution function of electrons and calculate the electron relaxation frequency includes:

[0015] During the process of electron-heavy particle collisions, use the kinetic equation with a collision term to describe the distribution function of electrons;

[0016] Perform a Taylor expansion on the collision term to obtain the Fokker-Planck collision term equation between the microscopic particles of the arc plasma;

[0017] Perform a second-order Taylor expansion on the Fokker-Planck collision term equation using the potential energy function to obtain the electron relaxation frequency.

[0018] The electron relaxation frequency includes: the collision slowing-down frequency of electrons and heavy particles, the deflection frequency of electrons and heavy particles, the parallel diffusion frequency of electrons and heavy particles, and the kinetic energy exchange frequency of electrons and heavy particles.

[0019] The data of the electrons and heavy particles include: the particle mass of the electrons and heavy particles, the particle number density of the electrons and heavy particles, the temperature of the electrons and heavy particles, and the charge of the electrons and heavy particles.

[0020] The kinetic equation with the collision term describes the distribution function of electrons, and the calculation formula is as follows:

[0021]

[0022] Among them, f is the distribution function of electrons, v is the velocity vector of electrons, r is the electron position vector, e is the electron charge, m e is the electron mass, E is the spatial electric field strength, t is the time, c is the collision term, h is other molecules except electrons, called heavy particles.

[0023] The Fokker - Planck collision term equation between the microscopic particles of the arc plasma is calculated as follows:

[0024]

[0025] Among them, f e is the distribution function of electrons, is the velocity vector of electrons, N = 1 is the dynamic friction coefficient, N = 2 is the dynamic diffusion coefficient, c is the collision term, h is other molecules except electrons, called heavy particles, and t is the time.

[0026] The electron relaxation frequency is calculated as follows:

[0027]

[0028] Among them, υ S is the collision moderation frequency between electrons and heavy particles, υ ⊥ is the deflection frequency between electrons and heavy particles, υ ∥ is the parallel diffusion frequency between electrons and heavy particles, υ K is the kinetic energy exchange frequency between electrons and heavy particles, H(v) is the Rosenbluth function of kinetic energy, G(v) is the Rosenbluth function of potential energy, u′ is the relative velocity between electrons and heavy particles, Γ is the gamma function, υ e is the velocity vector of electrons.

[0029] The energy change rate is calculated as follows:

[0030]

[0031] Among them, m α is the mass of the first particle, m β is the mass of the second particle, n αis the first particle number density, n β is the second particle number density, T α is the first particle temperature, T β is the second particle temperature, q α is the charge of the first particle, q β is the charge of the second particle, α is the first particle, β is the second particle, and either the first particle or the second particle is an electron or a heavy particle is the energy change rate between electrons and heavy particles, ε0 is the vacuum permittivity, InΛ is the Coulomb logarithm, and k is the Boltzmann constant

[0032] The relationship between the energy change rate and the temperature equilibrium time is calculated as follows

[0033]

[0034] where τ αβ is the temperature equilibrium time is the energy change rate between electrons and heavy particles, k is the Boltzmann constant, T α is the first particle temperature, T β is the second particle temperature

[0035] The relaxation times of electron-electron collisions, electron-heavy particle collisions, and heavy particle-heavy particle collisions are calculated based on the energy change rate and the relationship between the energy change rate and the temperature equilibrium time, and the calculation formulas are as follows

[0036]

[0037] where τ αβ is the temperature equilibrium time, i.e., the relaxation time, including: the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions, m α is the mass of the first particle, m β is the mass of the second particle, n α is the first particle number density, n β is the second particle number density, T α is the first particle temperature, T β is the second particle temperature, q α is the charge of the first particle, q β is the charge of the second particle, k is the Boltzmann constant, and InΛ is the Coulomb logarithm

[0038] In a second aspect, the present application proposes an evaluation device for the post-arc relaxation characteristics of an arc plasma, including

[0039] A frequency calculation module, which regards the process of the arc plasma transitioning from a non-equilibrium state to an equilibrium state as a process of heat transfer through collisions between electrons and heavy particles until the temperatures of the electrons and heavy particles are the same; during the process of heat transfer through collisions between electrons and heavy particles, the kinetic equation with a collision term is used to describe the distribution function of electrons and calculate the electron relaxation frequency;

[0040] A data acquisition module, which is used to acquire data of electrons and heavy particles;

[0041] A change rate calculation module, which is used to calculate the energy change rate caused by collisions between the two types of particles and the relationship between the energy change rate and the temperature equilibrium time according to the data of the electrons and heavy particles;

[0042] A relaxation time calculation module, which is used to calculate the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions according to the energy change rate and the relationship between the energy change rate and the temperature equilibrium time;

[0043] A relaxation time selection module, which is used to take the maximum value among the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions as the final relaxation time;

[0044] An evaluation result output module, which is used to take the electron relaxation frequency and the final relaxation time as the post-arc relaxation characteristics of the arc plasma.

[0045] In a third aspect, the present application proposes an electronic device, including: one or more processors, and a memory, where the memory is used to store instructions, and when the instructions are executed by the one or more processors, the one or more processors execute the above-mentioned method for evaluating the post-arc relaxation characteristics of an arc plasma.

[0046] In a fourth aspect, the present application proposes a computer-readable storage medium, which stores executable instructions, and when the instructions are executed, the processor executes the above-mentioned method for evaluating the post-arc relaxation characteristics of an arc plasma.

[0047] In a fifth aspect, the present application proposes a computer program product, including a computer program or instructions, and when the computer program or instructions are executed by a processor, the above-mentioned method for evaluating the post-arc relaxation characteristics of an arc plasma is implemented. Beneficial effects:

[0048] The present application proposes a method and device for evaluating the post-arc relaxation characteristics of an arc plasma, which uses a computer-aided design method to predict the post-arc relaxation characteristics of an arc plasma, ensuring the high precision of the prediction model and the accuracy of the prediction results. At the same time, it reduces the amount of experiments in the research and development of new insulating gases, reduces the research cost and design risk, and improves the research and development efficiency. Description of the Drawings

[0049] Figure 1 Flowchart of a method for evaluating the post-arc relaxation characteristics of an arc plasma according to an embodiment of the present invention;

[0050] Figure 2 Schematic diagram of the process of a method for evaluating the post-arc relaxation characteristics of an arc plasma according to an embodiment of the present invention;

[0051] Figure 3 Schematic diagram of the electron relaxation frequency of SF6 at a pressure of 0.7 MPa according to an embodiment of the present invention;

[0052] Figure 4 Schematic diagram of the electron kinetic energy exchange frequency of SF6 at different pressures according to an embodiment of the present invention;

[0053] Figure 5 Schematic diagram of the temperature equilibrium time between SF6 particles at a pressure of 0.7 MPa according to an embodiment of the present invention;

[0054] Figure 6 Temperature equilibrium time between electrons and heavy particles of SF6 at different pressures according to an embodiment of the present invention;

[0055] Figure 7 Principle block diagram of a device for evaluating the post-arc relaxation characteristics of an arc plasma according to an embodiment of the present invention. Detailed Description of the Embodiments

[0056] The following further describes in detail the specific embodiments of the present application in conjunction with the drawings and embodiments.

[0057] Embodiment 1:

[0058] This embodiment proposes a method for evaluating the post-arc relaxation characteristics of an arc plasma, as shown in Figure 1 、 Figure 2 , including:

[0059] Step S1: Consider the process of the arc plasma transitioning from a non-equilibrium state to an equilibrium state as a process of heat transfer through collisions between electrons and heavy particles until the temperatures of the electrons and heavy particles are the same;

[0060] In this embodiment, the post-arc relaxation characteristics of the arc plasma include the electron relaxation frequency and the final relaxation time. Steps S1 to S2 are used to calculate the electron relaxation frequency, and steps S3 to S6 are used to calculate the final relaxation time.

[0061] Step S2: During the process of heat transfer through collisions between electrons and heavy particles, describe the distribution function of electrons using the kinetic equation with a collision term, and calculate the electron relaxation frequency, including:

[0062] Step S2.1: During the heat transfer process of electrons colliding with heavy particles, the distribution function of electrons is described by a kinetic equation with a collision term.

[0063] The kinetic equation with a collision term describes the distribution function of electrons, and its calculation formula is as follows:

[0064]

[0065] where f is the distribution function of electrons, v is the velocity vector of electrons, r is the position vector of electrons, e is the electron charge, m e is the electron mass, E is the spatial electric field strength, t is time; c is the collision term, and h is the heavy particle (other molecules except electrons).

[0066] In this embodiment, for the kinetic equation describing the collision process between electrons e and heavy particles h (other particles) in non-equilibrium gas plasma, the Fokker-Planck kinetic theory equation is used to describe the motion state of electrons in the plasma, including the following assumptions: ① The particle collisions belong to the Markov process, that is, the state changes generated before and after particle collisions only depend on the current state of the particles themselves and have nothing to do with the past "history"; ② Multiple-particle collisions are equivalent to the superposition of a series of two-body collision effects.

[0067] Step S2.2: Perform a Taylor expansion on the collision term to obtain the Fokker-Planck collision term equation between the microscopic particles of the arc plasma.

[0068] The Fokker-Planck collision term equation between the microscopic particles of the arc plasma has the following calculation formula:

[0069]

[0070] where f e is the distribution function of electrons, is the velocity vector of electrons, and N = 1, 2 are respectively called the dynamic friction coefficient and the dynamic diffusion coefficient.

[0071] In this embodiment, a Taylor expansion is performed on the collision term on the right side of the kinetic equation to obtain the Fokker-Planck collision term form between the microscopic particles of the plasma, that is, the Fokker-Planck collision term equation.

[0072] Step S2.3: Perform a second-order Taylor expansion on the Fokker-Planck collision term equation using the potential energy function (Rosenbluth potential) to obtain the electron relaxation frequency.

[0073] The electronic relaxation frequencies include: the collision slowing-down frequency of electrons and heavy particles, the deflection frequency of electrons and heavy particles, the parallel diffusion frequency of electrons and heavy particles, and the kinetic energy exchange frequency of electrons and heavy particles. By comparing the four relaxation frequencies, the minimum frequency is selected to characterize the intensity of the electron-heavy particle kinetic energy exchange during the collision process.

[0074] The calculation formula for the electronic relaxation frequency is as follows:

[0075]

[0076] where υ S is the collision slowing-down frequency of electrons and heavy particles, υ ⊥ is the deflection frequency of electrons and heavy particles, υ ∥ is the parallel diffusion frequency of electrons and heavy particles, υ K is the kinetic energy exchange frequency of electrons and heavy particles, H(v) is the Rosenbluth function of kinetic energy, G(v) is the Rosenbluth function of potential energy, u′ is the relative velocity between electrons and heavy particles, Γ is the gamma function, and υ e is the velocity vector of electrons.

[0077] In this embodiment, first, according to the collision process between electrons and heavy particles in non-equilibrium gas plasma, the distribution function of electrons is described by the kinetic equation with a collision term. Since electrons and heavy particles in the plasma will undergo multiple small-angle collision processes within the Debye distance, electrons and heavy particles will interact with each other, causing electrons to move like Brownian particles. The motion state of electrons is characterized by the continuous occurrence of small random changes in their velocities, which can be described by the Fokker-Planck kinetic theory equation. The assumptions it makes about particle collisions are: ① Particle collisions belong to the Markov process, that is, the state changes generated before and after particle collisions only depend on the current state of the particles themselves and have nothing to do with the past "history"; ② Multiple particle collisions are equivalent to the superposition of a series of two-body collision effects. Second, a second-order Taylor expansion is performed on the collision term, and the Rosenbluth potential is used to represent the collision slowing-down frequency υ S (characterizing the rate at which the velocity of electrons decreases due to external forces in the incident direction), the deflection frequency υ ⊥ (characterizing the rate of kinetic energy dissipation caused by thermal motion of electrons in the direction perpendicular to the incident direction), the parallel diffusion frequency υ ∥ (characterizing the rate of kinetic energy dissipation caused by thermal motion of electrons in the direction parallel to the incident direction), and the kinetic energy exchange frequency υ K (characterizing the rate at which electrons exchange kinetic energy with heavy particles).

[0078] Through the above synthesis and programming calculations, the slowing-down frequency, deflection frequency, parallel diffusion frequency, and kinetic energy exchange frequency of electron collisions with heavy particles in the plasma can be obtained. The relaxation frequency reflects the speed of system recovery. The longer the relaxation time, the lower the relaxation frequency, indicating a slower system recovery speed; conversely, the shorter the relaxation time, the higher the relaxation frequency, indicating a faster system recovery speed. By comparing the four relaxation frequencies and selecting the minimum frequency, the electron-heavy particle relaxation frequency is mainly the kinetic energy exchange frequency between electrons and heavy particles, which characterizes the recovery characteristics of the non-equilibrium state to the equilibrium state during the collision process.

[0079] Step S3: Obtain the data of electrons and heavy particles, including: the particle masses of electrons and heavy particles, the particle number densities of electrons and heavy particles, the temperatures of electrons and heavy particles, and the electric charges of electrons and heavy particles.

[0080] Step S4: According to the data of the electrons and heavy particles, calculate the energy change rate caused by the collision of the two particles and the relationship between the energy change rate and the temperature equilibrium time;

[0081] The calculation formula for the energy change rate is as follows:

[0082]

[0083] where, m α is the mass of the first particle, m β is the mass of the second particle, n α is the number density of the first particle, n β is the number density of the second particle, T α is the temperature of the first particle, T β is the temperature of the second particle, q α is the electric charge of the first particle, q β is the electric charge of the second particle, α is the first particle, β is the second particle, and both the first particle and the second particle are electrons or heavy particles. is the energy change rate between electrons and heavy particles, ε0 is the vacuum permittivity, and InΛ is the Coulomb logarithm.

[0084] The calculation formula for the relationship between the energy change rate and the temperature equilibrium time is as follows:

[0085]

[0086] where, τ αβ is the temperature equilibrium time, is the energy change rate between electrons and heavy particles, and k is the Boltzmann constant.

[0087] Step S5: Calculate the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions according to the energy change rate and the relationship between the energy change rate and the temperature equilibrium time;

[0088] The calculation of the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions according to the energy change rate and the relationship between the energy change rate and the temperature equilibrium time is as follows:

[0089]

[0090] where τ αβ is the temperature equilibrium time, i.e., the relaxation time, including: the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions.

[0091] By applying the above calculation formulas to the temperature equilibrium processes between electron-electron, electron-heavy particle, and heavy particle-heavy particle respectively, the relaxation times can be obtained respectively, including the following calculation formulas:

[0092]

[0093] where τ ee is the relaxation time of electron-electron collisions, τ he is the relaxation time of electron-heavy particle collisions, τ hh is the relaxation time of heavy particle-heavy particle collisions, m e is the electron mass, ε0 is the vacuum permittivity, T e is the electron temperature, n e is the electron number density, e is the electron charge, m h is the heavy particle mass, T h is the heavy particle temperature, n h is the heavy particle number density, InΛ is the Coulomb logarithm, and Z is the heavy particle charge.

[0094] Step S6: Among the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions, take the largest value as the final relaxation time.

[0095] Step S7: Take the electron relaxation frequency and the final relaxation time as the post-arc relaxation characteristics of the arc plasma.

[0096] In this embodiment, after the circuit breaker is opened, the process of the arc plasma transitioning from a non-equilibrium state to an equilibrium state is, from a microscopic perspective, actually the intense heat transfer through collisions between high-temperature electrons and low-temperature heavy particles until the temperatures of the electrons and heavy particles are the same, and the system returns to the thermodynamic equilibrium state, that is, the traditional equilibrium plasma. The time required for this is the temperature equilibrium time of the plasma. Assuming the particle mass, particle number density, temperature, and charge of the two types of components in the plasma, the temperature equilibrium time between particles in the plasma is calculated by programming, including the temperature equilibrium time between electron-electron, electron-heavy particle, and heavy particle-heavy particle. After comparative analysis, the electron-heavy particle temperature equilibrium time τ he is used to characterize the time required for the non-equilibrium plasma to transition to the equilibrium state.

[0097] Furthermore, programming calculations are carried out: setting the pressure change, the initial values of each particle, defining and inputting various constants (electron temperature, vacuum permittivity, ideal gas constant, electron mass, Planck constant, etc.), calculating the partition function of each particle, solving the charge quasi-neutral equation, the slowing-down frequency, deflection frequency, parallel diffusion frequency, and kinetic energy exchange frequency of the collision between electrons and heavy particles, and the temperature equilibrium time between electron-electron, electron-heavy particle, and heavy particle-heavy particle. Further, the programming calculation is MATLAB R2022b.

[0098] Based on the above synthesis, the temperature equilibrium time between electron-electron, electron-heavy particle, and heavy particle-heavy particle in the plasma can be obtained. Comparing the three temperature equilibrium times, the electron-heavy particle temperature equilibrium time is the longest. Therefore, the electron-heavy particle temperature equilibrium time τ he is used to characterize the time required for the non-equilibrium CO2 / O2 plasma to transition to the equilibrium state.

[0099] Calculating the electron relaxation frequency and the final relaxation time can effectively evaluate the post-arc relaxation characteristics of the arc plasma, and quantitative analysis is carried out respectively from the relaxation frequency and relaxation time. High-voltage switchgear such as circuit breakers and disconnectors attach great importance to the thermal recovery and dielectric recovery processes during the post-arc stage when interrupting short-circuit currents. The post-arc recovery time of SF6 high-voltage circuit breakers is about 110 microseconds. And for the high-frequency arcs generated by repeated breakdowns during the opening and closing operations of disconnectors, the single-arc burning time is in the range of dozens of nanoseconds to several microseconds.

[0100] From existing research, using the thermodynamic non-equilibrium theory to study the dielectric recovery process in the current zero region is more in line with the actual working conditions of large-capacity electrical switchgear, and the post-arc relaxation time of the arc plasma of switchgear with different mixed gases as arc extinguishing media is evaluated and calculated.

[0101] Starting from the microscopic collision process of the plasma, the microscopic processes of the plasma (relaxation and transport processes) are studied deeply and systematically. The microscopic and macroscopic parameters of the non-equilibrium plasma are solved, and the interaction and relationship between the two are revealed, thus perfecting the electric arc theory, which can lay a theoretical foundation for the research on the breaking process of high-voltage switchgear such as circuit breakers and disconnectors.

[0102] Select SF6 insulating medium as the research object, and calculate its post-arc relaxation time of the arc plasma, as Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 shown. Figure 3 It is a schematic diagram of the SF6 electron relaxation frequency at a pressure of 0.7 MPa; Figure 4 It is a schematic diagram of the SF6 electron kinetic energy exchange frequency at different pressures; Figure 5 It is the temperature equilibrium time between particles in SF6 at a pressure of 0.7 MPa. Figure 6 It is the temperature equilibrium time between electrons and heavy particles in SF6 at different pressures.

[0103] Based on the research of plasma dynamics, this embodiment applies plasma dynamics and machine learning methods to the gas insulation field, and uses computer-aided design methods to predict the post-arc relaxation time of arc plasma, ensuring the high accuracy of the prediction model and the accuracy of the prediction results. At the same time, this system reduces the test volume in the research and development of new insulating gases, reduces the research cost and design risk, and improves the research and development efficiency. Through the above design and implementation, the post-arc relaxation time of arc plasma can be effectively evaluated, and useful tools and methods can be provided for the research and application in the gas insulation field.

[0104] Embodiment 2:

[0105] This embodiment proposes a device for evaluating the post-arc relaxation characteristics of arc plasma, as Figure 7 shown, including: a frequency calculation module, a data acquisition module, a change rate calculation module, a relaxation time calculation module, a relaxation time selection module, and an evaluation result output module;

[0106] The frequency calculation module is connected to the evaluation result output module, the data acquisition module is connected to the change rate calculation module, the change rate calculation module is connected to the relaxation time calculation module, the relaxation time calculation module is connected to the relaxation time selection module, and the relaxation time selection module is connected to the evaluation result output module;

[0107] A frequency calculation module, which regards the process of the arc plasma transitioning from a non-equilibrium state to an equilibrium state as a process of heat transfer through collisions between electrons and heavy particles until the temperatures of the electrons and heavy particles are the same; during the process of heat transfer through collisions between electrons and heavy particles, the distribution function of electrons is described by a kinetic equation with a collision term to calculate the electron relaxation frequency;

[0108] A data acquisition module, which is used to acquire data of electrons and heavy particles;

[0109] A change rate calculation module, which is used to calculate the energy change rate caused by collisions between the two types of particles and the relationship between the energy change rate and the temperature equilibrium time according to the data of the electrons and heavy particles;

[0110] A relaxation time calculation module, which is used to calculate the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions according to the energy change rate and the relationship between the energy change rate and the temperature equilibrium time;

[0111] A relaxation time selection module, which is used to take the largest value among the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions as the final relaxation time;

[0112] An evaluation result output module, which is used to take the electron relaxation frequency and the final relaxation time as the post-arc relaxation characteristics of the arc plasma.

[0113] Example 3:

[0114] This example proposes an electronic device, including: one or more processors, and a memory, where the memory is used to store instructions, and when the instructions are executed by the one or more processors, the one or more processors execute the method for evaluating the post-arc relaxation characteristics of an arc plasma as described above.

[0115] The electronic device can be a mobile phone, a computer, a tablet computer, etc., including a memory and a processor. A computer program is stored on the memory, and when the computer program is executed by the processor, it implements the method for evaluating the post-arc relaxation characteristics of an arc plasma as described in the example. It can be understood that the electronic device can also include an input / output (I / O) interface and a communication component.

[0116] Among them, the processor is used to execute all or part of the steps in the method for evaluating the post-arc relaxation characteristics of an arc plasma as described in the above example. The memory is used to store various types of data, which can include, for example, instructions of any application program or method in the electronic device, as well as data related to the application program.

[0117] The processor may be implemented by an Application Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), a Programmable Logic Device (PLD), a Field Programmable Gate Array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components, and is used to execute the method for evaluating the post-arc relaxation characteristics of an arc plasma described in the above embodiments.

[0118] Embodiment 4:

[0119] This embodiment provides a computer-readable storage medium storing executable instructions, which, when implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium.

[0120] This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method for evaluating the post-arc relaxation characteristics of an arc plasma described in various embodiments of the present application.

[0121] The aforementioned storage medium includes: flash memory, hard disk, multimedia card, card-type memory (e.g., SD (Secure Digital Memory Card) or DX (abbreviation for Memory Data Register, MDR), memory data register, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disk, server, APP (abbreviation for Application, application software), application store, and other media that can store program check codes. A computer program is stored thereon, and when the computer program is executed by a processor, it can implement each step of the method for evaluating the post-arc relaxation characteristics of an arc plasma described above.

[0122] Embodiment 5:

[0123] This embodiment provides a computer program product including a computer program or instructions, which, when executed by a processor, implement the method for evaluating the post-arc relaxation characteristics of an arc plasma described above.

[0124] Based on such understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or a part of the technical solution, may be embodied in the form of a computer program product.

[0125] Each embodiment in the present application is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the key point of each embodiment is to illustrate the differences from other embodiments.

[0126] The protection scope of the present application is not limited to the above embodiments. Obviously, those skilled in the art can make various changes and deformations to the present disclosure without departing from the scope and spirit of the present disclosure. If these changes and deformations fall within the scope of the claims of the present disclosure and their equivalent technologies, the intention of the present disclosure also includes these changes and deformations.

Claims

1. A method for evaluating the post-arc relaxation characteristics of an arc plasma, characterized in that, Including: Regarding the process of transforming arc plasma from non - equilibrium state to equilibrium state as the process of heat transfer through collisions between electrons and heavy particles until the temperatures of electrons and heavy particles are the same; During the process of heat transfer through collisions between electrons and heavy particles, using the kinetic equation with a collision term to describe the distribution function of electrons and calculating the electron relaxation frequency; Obtaining data of electrons and heavy particles; According to the data of the electrons and heavy particles, calculating the energy change rate caused by the collisions between the two kinds of particles and the relationship between the energy change rate and the temperature equilibrium time; According to the energy change rate and the relationship between the energy change rate and the temperature equilibrium time, calculating the relaxation time of electron - electron collisions, the relaxation time of electron - heavy particle collisions, and the relaxation time of heavy particle - heavy particle collisions; Among the relaxation time of electron - electron collisions, the relaxation time of electron - heavy particle collisions, and the relaxation time of heavy particle - heavy particle collisions, taking the largest value as the final relaxation time; Regarding the electron relaxation frequency and the final relaxation time as the post - arc relaxation characteristics of arc plasma.

2. The method for evaluating the post-arc relaxation characteristics of an arc plasma according to claim 1, characterized in that, During the process of heat transfer through collisions between electrons and heavy particles, using the kinetic equation with a collision term to describe the distribution function of electrons and calculating the electron relaxation frequency, including: During the process of collisions between electrons and heavy particles, using the kinetic equation with a collision term to describe the distribution function of electrons; Performing a Taylor expansion on the collision term to obtain the Fokker - Planck collision term equation between the microscopic particles of arc plasma; Performing a second - order Taylor expansion on the Fokker - Planck collision term equation using the potential energy function to obtain the electron relaxation frequency.

3. The method for evaluating the post-arc relaxation characteristics of an arc plasma according to claim 1, characterized in that, The electron relaxation frequency includes: the collision slowing - down frequency between electrons and heavy particles, the deflection frequency between electrons and heavy particles, the parallel diffusion frequency between electrons and heavy particles, and the kinetic energy exchange frequency between electrons and heavy particles.

4. The method for evaluating the post-arc relaxation characteristics of an arc plasma according to claim 1, wherein The data of the electrons and heavy particles include: the particle mass of electrons and heavy particles, the particle number density of electrons and heavy particles, the temperature of electrons and heavy particles, and the charge of electrons and heavy particles.

5. The method for evaluating the post-arc relaxation characteristics of an arc plasma according to claim 2, wherein The kinetic equation with a collision term describes the distribution function of electrons, and the calculation formula is as follows: where f is the distribution function of electrons, v is the velocity vector of electrons, r is the position vector of electrons, e is the electric charge of electrons, m e is the mass of electrons, E is the spatial electric field strength, t is time, c is the collision term, and h is other molecules except electrons, called heavy particles.

6. The method for evaluating the post-arc relaxation characteristics of an arc plasma according to claim 2, wherein The Fokker - Planck collision term equation between the microscopic particles of arc plasma, and the calculation formula is as follows: where f e is the distribution function of electrons, is the velocity vector of electrons, N = 1 is the dynamic friction coefficient, N = 2 is the dynamic diffusion coefficient, c is the collision term, h is other molecules except electrons, called heavy particles, and t is time.

7. The method for evaluating the post-arc relaxation characteristics of an arc plasma according to claim 2, wherein The electron relaxation frequency, and the calculation formula is as follows: Among them, υ S is the collision moderation frequency of electrons and heavy particles, υ ⊥ is the deflection frequency of electrons and heavy particles, υ ∥ is the parallel diffusion frequency of electrons and heavy particles, υ K is the kinetic energy exchange frequency of electrons and heavy particles, H(v) is the Rosenbluth function of kinetic energy, G(v) is the Rosenbluth function of potential energy, u′ is the relative velocity between electrons and heavy particles, Γ is the gamma function, υ e is the velocity vector of electrons.

8. A method for evaluating the post-arc relaxation characteristics of an arc plasma, according to claim 1, characterized in that, The energy change rate, and the calculation formula is as follows: where m α is the mass of the first particle, m β is the mass of the second particle, n α is the number density of the first particle, n β is the number density of the second particle, T α is the temperature of the first particle, T β is the temperature of the second particle, q α is the electric charge of the first particle, q β is the electric charge of the second particle, α is the first particle, β is the second particle, and both the first particle and the second particle are electrons or heavy particles. is the energy change rate between electrons and heavy particles, ε0 is the vacuum permittivity, InΛ is the Coulomb logarithm, and k is the Boltzmann constant.

9. The method for evaluating the post-arc relaxation characteristics of an arc plasma according to claim 8, wherein The relationship between the energy change rate and the temperature equilibrium time, and the calculation formula is as follows: Among them, τ αβ is the temperature equilibrium time, is the energy change rate between electrons and heavy particles, k is the Boltzmann constant, T α is the temperature of the first particle, T β is the temperature of the second particle.

10. The method for evaluating the post-arc relaxation characteristics of an arc plasma according to claim 9, wherein According to the energy change rate and the relationship between the energy change rate and the temperature equilibrium time, calculating the relaxation time of electron - electron collisions, the relaxation time of electron - heavy particle collisions, and the relaxation time of heavy particle - heavy particle collisions, and the calculation formula is as follows: Among them, τ αβ is the temperature equilibrium time, i.e., the relaxation time, including: the relaxation time of electron-electron collision, the relaxation time of electron-heavy particle collision, and the relaxation time of heavy particle-heavy particle collision, m α is the mass of the first particle, m β is the mass of the second particle, n α is the number density of the first particle, n β is the number density of the second particle, T α is the temperature of the first particle, T β is the temperature of the second particle, q α is the charge of the first particle, q β is the charge of the second particle, k is the Boltzmann constant, and InΛ is the Coulomb logarithm.

11. An evaluation device for the post-arc relaxation characteristics of an arc plasma, characterized in that, Including: A frequency calculation module, which is used to regard the process of transforming arc plasma from non - equilibrium state to equilibrium state as the process of heat transfer through collisions between electrons and heavy particles until the temperatures of electrons and heavy particles are the same; during the process of heat transfer through collisions between electrons and heavy particles, using the kinetic equation with a collision term to describe the distribution function of electrons and calculating the electron relaxation frequency; A data acquisition module, which is used to obtain data of electrons and heavy particles; A change rate calculation module, which is used to calculate the energy change rate caused by the collisions between the two kinds of particles and the relationship between the energy change rate and the temperature equilibrium time according to the data of the electrons and heavy particles; A relaxation time calculation module, configured to calculate the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions according to the energy change rate and the relationship between the energy change rate and the temperature equilibrium time; A relaxation time selection module, configured to select the maximum value among the relaxation time of electron-electron collisions, the relaxation time of electron-heavy particle collisions, and the relaxation time of heavy particle-heavy particle collisions as the final relaxation time; An evaluation result output module, configured to use the electron relaxation frequency and the final relaxation time as the post-arc relaxation characteristics of the arc plasma; 12. An electronic device, characterized in that, Comprising: One or more processors, and a memory, the memory is used to store instructions, when the instructions are executed by the one or more processors, the one or more processors execute an arc plasma post-arc relaxation characteristic evaluation method according to any one of claims 1 to 10; 13. A computer-readable storage medium, characterized in that, It stores executable instructions, and when the instructions are executed, the processor executes an arc plasma post-arc relaxation characteristic evaluation method according to any one of claims 1 to 10; 14. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instruction is executed by the processor, it implements an arc plasma post-arc relaxation characteristic evaluation method according to any one of claims 1 to 10;

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