Simulation method of dielectric discharge pulse based on full current law

Abstract

The invention discloses a method for simulating the discharge pulse of an insulating medium based on the full current law. In the method, the electric field calculation control equation taking into account the full current is used to replace the Poisson equation in the fluid dynamics drift diffusion model and the bipolar load sub-model, and the coupling relationship between the electric field calculation control equation taking into account the full current and the current continuity equation is supplemented, and a finite element model based on the full current law is constructed, so as to realize the simulation calculation of the discharge of the insulating medium considering the influence of the conduction current and the interface charge. In the method, the insulating medium in the electrical circuit is equivalent to a current source, and the output current of the current source is used as the calculation condition of the current source port voltage, which is solved by the finite element model based on the full current law, and the current source port voltage calculated according to the output current and Kirchhoff's law is used as the boundary condition of the finite element model based on the full current law. This field-circuit coupling form of the calculation model realizes the simulation of the pulse current caused by the discharge of the insulating medium.

Description

Technical Field

[0001] The invention belongs to the technical field of insulation discharge simulation, and in particular relates to an insulation medium discharge pulse simulation method based on the full current law. Background Art

[0002] As one of the most common solid-liquid composite insulation forms in power systems, the discharge characteristics and mechanisms of oil-paper insulation have attracted much attention, especially the mathematical description and simulation methods of discharge phenomena in oil-paper insulation have become a research hotspot. Simulation calculation has not only become an effective supplement to experimental methods, but also the only way to explore discharge characteristics and mechanisms without experimental conditions. However, in the oil-paper insulation system, due to its high molecular density, the mathematical model of gas discharge, the Monte Carlo collision model, cannot be directly used, and the dynamic simulation model is not easy to solve the complex model system. Therefore, domestic and foreign scholars proposed a fluid dynamics drift diffusion model based on dynamics theory to describe the discharge phenomenon in liquid insulating media, and proposed a bipolar charge submodel to describe the charge migration phenomenon in solid insulating media, thereby obtaining a simulation method for the discharge phenomenon in the oil-paper insulation system.

[0003] However, the existing simulation calculation methods mainly have the following problems: the Poisson equation in the electrostatic field is used as the control equation for electric field calculation in the existing models, which cannot consider the influence of polarization charge at the interface between liquid and solid, nor can it calculate the conduction current in the insulating medium, and is difficult to apply to electric stress environments containing DC components; the existing methods can only calculate the electric field distribution and charge distribution accompanying the development process of the streamer, and have not realized the simulation of the external circuit pulse current induced by the streamer, resulting in difficulty in establishing the intrinsic connection between the microscopic charge movement and the macroscopic discharge pulse.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0005] The existing fluid dynamics drift diffusion model and bipolar charge carrier migration model both use Gauss's theorem (Poisson's equation) as the electric field calculation control function, without considering the influence of the conduction current and interface polarization charge caused by the conductivity of the insulating medium, and cannot be applied to the electric stress environment containing a DC component. The purpose of the present invention is to provide an insulating medium discharge pulse simulation method based on the full current law, which can not only solve the electric field distribution, charge distribution, and current density distribution accompanying the dielectric discharge process in the electric stress environment containing a DC component, but also realize the field-circuit coupling simulation of the external circuit pulse current induced by the discharge. In order to achieve the above purpose, the present invention provides the following technical solutions:

[0006] A method for simulating an insulating medium discharge pulse based on the full current law, characterized in that it comprises the following steps:

[0007] The first step is to measure the material parameters of the insulating medium, collect the ambient temperature T of the insulating medium, the ambient temperature is in Kelvin, and determine the structure and parameters of the electrical circuit that triggers the discharge of the insulating medium. The insulating medium includes liquid medium and solid medium, wherein:

[0008] The insulating medium material parameters include the relative dielectric constant ε of the insulating medium r , the conductivity of the insulating medium σ, the negative charge injection barrier ω in the insulating medium e and the positive charge injection barrier ω p , positive charge mobility μ in insulating medium p and negative charge mobility μ e ;

[0009] The electrical circuit includes a power supply system, circuit components, and an insulating medium as a load; the circuit components include resistors, capacitors, and inductors; the parameters of the electrical circuit include the voltage waveform and amplitude output by the power supply system, the resistance value of the resistor, the capacitance value of the capacitor, and the inductance value of the inductor; the structure of the electrical circuit refers to the connection arrangement structure between the power supply system, the circuit components, and the insulating medium, wherein the insulating medium is connected to the power supply system or the circuit components through the electrode boundary; the electrical circuit provides an electric field environment for the insulating medium and enables the insulating medium to withstand voltage and flow current;

[0010] In the second step, based on the fluid dynamics drift diffusion model and the bipolar load sub-model, the finite element simulation calculation model of the discharge evolution process in the liquid insulating medium and the solid insulating medium is constructed respectively. In the finite element simulation calculation model, the Poisson equation is used as the electrostatic field calculation control equation:

[0011] In the fluid dynamics drift-diffusion model:

[0012] In the bipolar charge submodel: Where ε0 is the dielectric constant of vacuum; E is the electric field; ρ p , n , e are the charge densities of positive ions, negative ions and electrons in the liquid medium respectively; ρ hμ , ht , eμ , et are the charge densities of free holes, trapped holes, free electrons, and trapped electrons in solid media, respectively;

[0013] The third step is to supplement the conduction current density term and the external current density term in the electrostatic field calculation control equation based on the full current law to construct the electric field calculation control equation taking into account the full current:

[0014] Where t is the simulation time; E is the electric field; J and J o are the total current density in the insulating medium and the external current density respectively; the electric field calculation control equation taking into account the total current can simultaneously reflect the electrostatic field effect and the constant electric field effect;

[0015] The fourth step is to replace the Poisson equation in the finite element simulation calculation model with the electric field calculation control equation taking into account the full current, and establish a coupling relationship between the electric field calculation control equation taking into account the full current and the current continuity equation:

[0016] In the fluid dynamics drift-diffusion model:

[0017] In the bipolar charge submodel:

[0018] In this way, a finite element model based on the full current law is constructed;

[0019] The fifth step is to set ti as the simulation calculation time corresponding to the i-th simulation progress; i is a serial number parameter and satisfies i=0, 1, 2...., N d ; N d The number of simulation calculation steps is specified; the insulating medium in the electrical circuit is equivalent to a current source, and the output current of the current source is zero at time t0;

[0020] In t i At this moment, according to the structure and parameters of the electrical circuit and the output current of the current source, Kirchhoff's law and the voltage-current relationship of the circuit components are used to calculate the voltage at the current source port;

[0021] The sixth step is to substitute the current source port voltage as a boundary condition into the finite element model based on the full current law, and use the finite element model based on the full current law to calculate the electric field distribution and charge distribution at the boundary of the insulating medium electrode, and calculate the current at the electrode boundary through the electric field and charge:

[0022] Negative Polarity Boundary:

[0023] Positive Polarity Boundary: Where s is the integral path of the electrode boundary; A is the Richardson constant; q is the unit charge; k B is the Boltzmann constant; J e With J pThey represent the current density at the negative polarity boundary and the positive polarity boundary respectively, and their directions are perpendicular to the interface normal vector and in the same direction as the electric field; C ext is the extraction coefficient; ρ pos With μ p are the density and mobility of positive charge respectively; ρ neg With μ e are the density and mobility of negative charge respectively; I e with I p are the currents at the negative electrode and the positive electrode respectively, and their directions are consistent with the direction of the electric field, I e with I p It is obtained by line integral in a two-dimensional model and by surface integral in a three-dimensional model. The positive charge in a liquid medium refers to positive ions and in a solid medium refers to free holes. The negative charge in a liquid medium refers to electrons and in a solid medium refers to free electrons.

[0024] Step 7: Select I when the boundary voltage is positive p , when the boundary voltage is negative, select I e , the selected current is taken as t i+1 The output current of the current source at time t i+1 The current source port voltage at the moment; and so on, until the simulation reaches the specified number of advancements, the simulation ends.

[0025] Preferably, the extraction coefficient C ext The value range is 0 to 1.

[0026] Preferably, the finite element model based on the full current law is used alone for dielectric discharge simulation to calculate the electric field distribution and charge distribution accompanying the dielectric discharge process in an electric field environment containing a DC component.

[0027] Preferably, the electric field environment includes a direct current electric field, an alternating current electric field, a pulse electric field, and a superimposed composite electric field thereof.

[0028] Preferably, the method finally obtains the electric field distribution, charge distribution, current density distribution inside the insulating medium, and the pulse current waveform caused by the discharge of the insulating medium.

[0029] In the above technical scheme, the present invention provides an insulating medium discharge pulse simulation method based on the full current law, which has the following beneficial effects: using the full current law to correct the drift diffusion model and the bipolar charge sub-model, it can not only reflect the law of the electrostatic field, but also reflect the law of the constant electric field; it can calculate the displacement current, but also the conduction current; it can not only simulate the internal electric field distribution, charge distribution, and current density distribution of the insulating medium accompanying the discharge development process under the action of the external circuit, but also calculate the pulse current induced by the discharge process in the external circuit. This method can be used not only for oil-paper insulation systems, but also for any liquid-solid two-phase insulation system or liquid, solid single-phase insulation system, and only needs to set the corresponding parameters according to the dielectric properties. The discharge phenomenon that can be described by the present invention can be not only streamer discharge, but also surface discharge or corona discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0031] Figure 1(a) to Figure 1(b) The results of the prior art model calculating the oil-paper interface charge and potential under AC / DC composite voltage, where 1(a) is the curve of the maximum polarization charge density at the interface changing with time, and 1(b) is the curve of the interface potential changing with time;

[0032] Figure 2(a) to Figure 2(b) The results of calculating the charge and potential of the oil-paper interface under AC / DC composite voltage by the model of the present invention, wherein 2(a) is the curve of the maximum polarization charge density at the interface changing with time, and 2(b) is the curve of the interface potential changing with time;

[0033] Figure 3(a) to Figure 3(b) The model of the present invention calculates the external circuit pulse current induced by oil-paper insulation discharge under AC / DC composite voltage, where 3(a) is an underdamped oscillating current pulse and 3(b) is an overdamped single-peak current pulse. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Therefore, the following Figure 1(a) to Figure 3(b) The detailed description of the embodiments of the present invention provided in the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0041] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. A method for simulating an insulating medium discharge pulse based on the full current law includes:

[0042] A method for simulating an insulating medium discharge pulse based on the full current law, characterized in that it comprises the following steps:

[0043] The first step is to measure the material parameters of the insulating medium, collect the ambient temperature T of the insulating medium, the ambient temperature is in Kelvin, and determine the structure and parameters of the electrical circuit that triggers the discharge of the insulating medium. The insulating medium includes liquid medium and solid medium, wherein:

[0044] The insulating medium material parameters include the relative dielectric constant ε of the insulating medium r , the conductivity of the insulating medium σ, the negative charge injection barrier ω in the insulating medium e and the positive charge injection barrier ω p , positive charge mobility μ in insulating medium p and negative charge mobility μ e ;

[0045] The electrical circuit includes a power supply system, circuit components, and an insulating medium as a load; the circuit components include resistors, capacitors, and inductors; the parameters of the electrical circuit include the voltage waveform and amplitude output by the power supply system, the resistance value of the resistor, the capacitance value of the capacitor, and the inductance value of the inductor; the structure of the electrical circuit refers to the connection arrangement structure between the power supply system, the circuit components, and the insulating medium, wherein the insulating medium is connected to the power supply system or the circuit components through the electrode boundary; the electrical circuit provides an electric field environment for the insulating medium and enables the insulating medium to withstand voltage and flow current;

[0046] In the second step, based on the fluid dynamics drift diffusion model and the bipolar load sub-model, the finite element simulation calculation model of the discharge evolution process in the liquid insulating medium and the solid insulating medium is constructed respectively. In the finite element simulation calculation model, the Poisson equation is used as the electrostatic field calculation control equation:

[0047] In the fluid dynamics drift-diffusion model:

[0048] In the bipolar charge submodel: Where ε0 is the dielectric constant of vacuum; E is the electric field; ρ p , n , e are the charge densities of positive ions, negative ions and electrons in the liquid medium respectively; ρ hμ , ht , eμ , et are the charge densities of free holes, trapped holes, free electrons, and trapped electrons in solid media, respectively;

[0049] The third step is to supplement the conduction current density term and the external current density term in the electrostatic field calculation control equation based on the full current law to construct the electric field calculation control equation taking into account the full current:

[0050] Where t is the simulation time; E is the electric field; J and J o are the total current density in the insulating medium and the external current density respectively; the electric field calculation control equation taking into account the total current can simultaneously reflect the electrostatic field effect and the constant electric field effect;

[0051] The fourth step is to replace the Poisson equation in the finite element simulation calculation model with the electric field calculation control equation taking into account the full current, and establish a coupling relationship between the electric field calculation control equation taking into account the full current and the current continuity equation:

[0052] In the fluid dynamics drift-diffusion model:

[0053] In the bipolar charge submodel:

[0054] In this way, a finite element model based on the full current law is constructed;

[0055] The fifth step is to set t i is the simulation calculation time corresponding to the i-th simulation progress; i is a serial number parameter and satisfies i=0, 1, 2...., N d ; N d The number of simulation calculation steps is specified; the insulating medium in the electrical circuit is equivalent to a current source, and the output current of the current source is zero at time t0;

[0056] In t i At this moment, according to the structure and parameters of the electrical circuit and the output current of the current source, Kirchhoff's law and the voltage-current relationship of the circuit components are used to calculate the voltage at the current source port;

[0057] The sixth step is to substitute the current source port voltage as a boundary condition into the finite element model based on the full current law, and use the finite element model based on the full current law to calculate the electric field distribution and charge distribution at the boundary of the insulating medium electrode, and calculate the current at the electrode boundary through the electric field and charge:

[0058] Negative Polarity Boundary:

[0059] Positive Polarity Boundary: Where s is the integral path of the electrode boundary; A is the Richardson constant; q is the unit charge; k B is the Boltzmann constant; J e With J p They represent the current density at the negative polarity boundary and the positive polarity boundary respectively, and their directions are perpendicular to the interface normal vector and in the same direction as the electric field; C ext is the extraction coefficient; ρ pos With μ p are the density and mobility of positive charge respectively; ρ neg With μ e are the density and mobility of negative charge respectively; I e with I p are the currents at the negative electrode and the positive electrode respectively, and their directions are consistent with the direction of the electric field, I e with I p It is obtained by line integral in a two-dimensional model and by surface integral in a three-dimensional model. The positive charge in a liquid medium refers to positive ions and in a solid medium refers to free holes. The negative charge in a liquid medium refers to electrons and in a solid medium refers to free electrons.

[0060] Step 7: Select I when the boundary voltage is positive p , when the boundary voltage is negative, select I e , the selected current is taken as t i+1 The output current of the current source at time t i+1 The current source port voltage at the moment; and so on, until the simulation reaches the specified number of advancements, the simulation ends.

[0061] The following example uses an oil-paper insulated needle plate electrode with a 1:1 AC / DC composite voltage:

[0062] C ext Take 0.8;

[0063] Since it is a 1:1 AC / DC composite voltage, there is a polarity reversal. Therefore, an if statement is added during the calculation process. When the boundary voltage is greater than 0, I p , when the boundary voltage is less than 0, take I eWhen the boundary voltage is equal to 0, the judgment is made according to the voltage state of the previous advancement number.

[0064] The implementation results are shown as follows (taking the oil-paper insulated needle plate electrode with a 1:1 AC / DC composite voltage as an example):

[0065] 1) Modification of existing simulation method based on full current law

[0066] The curves of the steady-state partial pressure (when no streamer is generated) and the maximum polarization charge density at the interface changing with time before and after the model improvement are shown in Figure 2. Figure 1(a) to Figure 1(b) and Figure 2(a) to Figure 2(b) As shown in the figure, by comparison, the original model cannot calculate the polarization charge at the interface under AC / DC composite voltage, and the interface potential cannot reflect the polarization (charging) process. The improved model solves the above problems.

[0067] As is known to all, the polarization charge at the oil-paper interface acts as a barrier to the development of dielectric discharge. In an electric field environment containing a DC component, it is inaccurate to calculate the electric field distribution and charge distribution of the discharge process without considering the polarization charge. The applicant explored the following to solve the discharge simulation under the action of the DC component:

[0068] Initially, the applicant approximated the interface polarization charge under the extremely non-uniform electric field within the needle tip range as a uniform distribution, and only set it as an initial condition in the simulation model (without the control equation to continuously calculate it). From the perspective of simulation model construction (mathematical control equation), there are still large errors. In fact, the applicant initially used the method of setting the initial conditions of the interface charge to equate the interface polarization charge. Although the discharge law under the action of the DC component was studied to a certain extent, there are two sources of error: (1) The interface charge is a function of position: the interface charge distribution under the extremely non-uniform electric field is non-uniform and cannot be replaced by a constant; (2) The interface charge is a function of time: the interface charge changes dynamically with the change of the electric field and the development of the discharge, and cannot be simply equivalent to the initial condition or constant.

[0069] To further solve the above problems, the applicant thought that the fundamental reason for the generation of interfacial polarization charge is that the voltage is distributed according to the resistance, and the conduction current generates polarization charge. Therefore, the conduction current term can be added to the original displacement current to form the "total current". Finally, the original model was corrected using the total current law.

[0070] 2) Implementation of streamer discharge field-circuit coupling simulation calculation

[0071] In the early stage, in order to simulate the pulse current induced by the streamer, the applicant used the capacitance and resistance parameters to simulate the residual oil gap, used the variable resistor to simulate the equivalent resistance of the streamer channel, and constructed a multi-level equivalent circuit network model in a decoupled form to calculate the pulse current induced by the streamer in the loop. Although a good fitting effect was obtained for the rising edge of the pulse signal, the calculation of the circuit parameters was based on the finite element simulation results, which only reflected the influence of the "field" on the "path", and did not reflect the influence of the "path" on the "field". In addition, the uniform approximation and piecewise discrete processing were used in the parameter calculation, resulting in certain errors in the calculation results.

[0072] Based on preliminary attempts, the applicant discovered that the essence of the streamer inducing the generation of pulse current in the external circuit is that the discharge channel changes the equivalent capacitance and equivalent resistance of the insulating medium. If the discharge model is regarded as a time-varying RC circuit, and the current of this circuit is fed back to the external circuit, the external circuit will generate a new voltage divider at the discharge model port. The new voltage divider will cause the streamer to develop (RC parameters change), and a new current will be obtained. By iterating repeatedly in this way, the pulse current can be accurately calculated at each time step. This is how the field-circuit coupling simulation method for streamers and their induced pulse currents described in this scheme is derived. From the simulation results, it can be seen that Figure 3(a) to Figure 3(b) As shown, this method can simulate underdamped oscillatory current pulses in discharge, and can also simulate overdamped single-peak current pulses in discharge.

[0073] Finally, it should be noted that the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making any creative work are within the scope of protection of the present application.

[0074] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for simulating an insulating medium discharge pulse based on the full current law, characterized in that: It includes the following steps: The first step is to measure the material parameters of the insulating medium and collect the ambient temperature of the insulating medium. T , the ambient temperature is in Kelvin, and determines the structure and parameters of the electrical circuit that triggers the discharge of the insulating medium. The insulating medium includes liquid medium and solid medium, among which, The insulating medium material parameters include the relative dielectric constant of the insulating medium , conductivity of insulating medium σ , Negative charge injection barrier in insulating medium Positive charge injection barrier , Positive charge mobility in insulating medium Negative charge mobility ; The electrical circuit includes a power supply system, circuit components, and an insulating medium as a load; the circuit components include resistors, capacitors, and inductors; the parameters of the electrical circuit include the voltage waveform and amplitude output by the power supply system, the resistance value of the resistor, the capacitance value of the capacitor, and the inductance value of the inductor; the structure of the electrical circuit refers to the connection arrangement structure between the power supply system, the circuit components, and the insulating medium, wherein the insulating medium is connected to the power supply system or the circuit components through the electrode boundary; the electrical circuit provides an electric field environment for the insulating medium and enables the insulating medium to withstand voltage and flow current; In the second step, based on the fluid dynamics drift diffusion model and the bipolar load sub-model, the finite element simulation calculation model of the discharge evolution process in the liquid insulating medium and the solid insulating medium is constructed respectively. In the finite element simulation calculation model, the Poisson equation is used as the electrostatic field calculation control equation: In the fluid dynamics drift-diffusion model: ; In the bipolar charge submodel: ,in, is the dielectric constant of vacuum; E is the electric field; p , n , e are the charge densities of positive ions, negative ions, and electrons in the liquid medium, respectively; , ht , , et are the charge densities of free holes, trapped holes, free electrons, and trapped electrons in solid media, respectively; The third step is to supplement the conduction current density term and the external current density term in the electrostatic field calculation control equation based on the full current law to construct the electric field calculation control equation taking into account the full current: ,in, t Calculate time for simulation; E is the electric field; J and J o are the total current density in the insulating medium and the external current density respectively; the electric field calculation control equation taking into account the total current can simultaneously reflect the electrostatic field effect and the constant electric field effect; The fourth step is to replace the Poisson equation in the finite element simulation calculation model with the electric field calculation control equation taking into account the full current, and establish a coupling relationship between the electric field calculation control equation taking into account the full current and the current continuity equation: In the fluid dynamics drift-diffusion model: ; In the bipolar charge submodel: ; In this way, a finite element model based on the full current law is constructed; The fifth step is to set t i is the simulation calculation time corresponding to the i-th simulation progress; i is a serial parameter and satisfies i=0,1,2....,N d ;N d The number of simulation calculation steps is specified; the insulating medium in the electrical circuit is equivalent to a current source, and the output current of the current source is zero at time t0; In t i At this moment, according to the structure and parameters of the electrical circuit and the output current of the current source, Kirchhoff's law and the voltage-current relationship of the circuit components are used to calculate the voltage at the current source port; The sixth step is to substitute the current source port voltage as a boundary condition into the finite element model based on the full current law, and use the finite element model based on the full current law to calculate the electric field distribution and charge distribution at the boundary of the insulating medium electrode, and calculate the current at the electrode boundary through the electric field and charge: Negative Polarity Boundary: ; Positive Polarity Boundary: ; in, s is the integration path of the electrode boundary; A is the Richardson constant; q is the unit charge; k B is the Boltzmann constant; J e and J p They represent the current density at the negative polarity boundary and the positive polarity boundary, respectively, and their directions are perpendicular to the interface normal vector and in the same direction as the electric field; C ext is the extraction coefficient; and are the density and mobility of positive charge respectively; and are the density and mobility of negative charge respectively; I e and I p are the currents at the negative electrode and the positive electrode respectively, and their directions are consistent with the direction of the electric field. I e and I p It is obtained by line integral in a two-dimensional model and by surface integral in a three-dimensional model. The positive charge in a liquid medium refers to positive ions and in a solid medium refers to free holes. The negative charge in a liquid medium refers to electrons and in a solid medium refers to free electrons. Step 7: Select when the boundary voltage is positive I p , when the boundary voltage is negative, select I e , the selected current is taken as t i+1 The output current of the current source at time t i+1 The current source port voltage at the moment; and so on, until the simulation reaches the specified number of advancements, the simulation ends.

2. The method for simulating an insulating medium discharge pulse based on the full current law according to claim 1, characterized in that: Extraction coefficient C ext The value range is 0 to 1.

3. The method for simulating an insulating medium discharge pulse based on the full current law according to claim 1, characterized in that: The finite element model based on the full current law is used alone for dielectric discharge simulation to calculate the electric field distribution and charge distribution accompanying the dielectric discharge process in an electric field environment containing a DC component.

4. The method for simulating an insulating medium discharge pulse based on the full current law according to claim 1, characterized in that: The electric field environment includes a direct current electric field, an alternating current electric field, a pulse electric field, and a superimposed composite electric field thereof.

5. The method for simulating an insulating medium discharge pulse based on the full current law according to claim 1, characterized in that: The method finally obtains the electric field distribution, charge distribution, current density distribution inside the insulating medium, and the pulse current waveform caused by the discharge of the insulating medium.

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