Cable insulation space charge simulation method and device based on aging factor coupling

Abstract

The invention discloses a cable insulation space charge simulation method and device based on aging factor coupling, and relates to the technical field of electrical engineering. The method comprises the following steps: establishing a bipolar carrier charge transport model, wherein model parameters comprise a detrapping coefficient and a diffusion coefficient; sampling the cable insulation, and measuring the isothermal relaxation current of the sample to calculate the aging factor of the sample; measuring the actual carrier mobility of the sample by using a time-of-flight method; a detrapping coefficient is updated based on the aging factor, a diffusion coefficient is updated based on the actual carrier mobility, and an aging factor coupling type insulation charge transport model is obtained; and carrying out numerical solution on the aging factor coupling type insulation charge transport model to obtain simulation data of space charge distribution and local electric field change of cable insulation. According to the technical scheme, space charge distribution and local electric field change of cable insulation are accurately simulated, and scientific evaluation can be provided for the aging state of cable insulation.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electrical engineering, and in particular to a cable insulation space charge simulation method and device based on coupling of an aging factor. BACKGROUND

[0002] In modern power systems and electronic equipment, the electrical performance of insulating materials is crucial to the safety and reliability of the system; with the development of high-voltage technology, the operating voltage of power equipment is continuously increasing, and higher requirements are put forward for the withstand voltage and long-term stability of insulating materials; one of the main factors restricting the development of polymer insulation DC cables for a long time is the treeing breakdown caused by the accumulation of space charges in polymer solid dielectric under DC high voltage, and therefore it is of great significance to establish an insulation charge transport model and predict the service life of insulating materials for improving the electric field distribution in the cable, optimizing the cable structure design, improving the insulation performance of the DC cable, and prolonging the service life of the cable.

[0003] In existing research, the bipolar carrier charge transport model proposed by J.M.Alison and R.M.Hill can dynamically simulate the migration, diffusion, trapping and detrapping of space charges, and after attempts and improvement by different scholars, the theoretical space charge distribution obtained under the condition of a flat electrode is similar to the measurement result; however, the bipolar carrier transport model under the condition of aging, which is extremely important and closer to the actual situation, has not been reported, and it is still blank in the current field of polymer insulation research; during the long-term operation of cable insulation materials, the materials are gradually aged under the combined action of power, heat, mechanical stress and environmental factors, and their physical, chemical and electrical properties are gradually deteriorated, thereby increasing the risk of equipment failure and safety hazards, and therefore it is urgent to propose a bipolar carrier transport model that is more in line with the actual aging condition of cable insulation, so as to accurately simulate the space charge distribution and local electric field change of the cable insulation and provide a more scientific evaluation of the aging state of the insulation. SUMMARY

[0004] The application provides a cable insulation space charge simulation method based on coupling of an aging factor, which aims to accurately simulate the space charge distribution and local electric field change of the cable insulation and provide a scientific evaluation of the aging state of the insulation.

[0005] The cable insulation space charge simulation method based on coupling of an aging factor provided by the application comprises the following steps:

[0006] S1, a bipolar carrier charge transport model is established, and the parameters of the bipolar carrier charge transport model include a detrapping coefficient and a diffusion coefficient;

[0007] S2, sampling the cable insulation, measuring the isothermal relaxation current of the sample to calculate the aging factor of the sample; measuring the actual carrier mobility of the sample by using the time-of-flight method;

[0008] S3, updating the detrapping coefficient based on the aging factor, updating the diffusion coefficient based on the actual carrier mobility, to obtain an aging factor coupled insulation charge transport model;

[0009] S4, numerically solving the aging factor coupled insulation charge transport model to obtain simulation data of the spatial charge distribution and local electric field change of the cable insulation.

[0010] Optionally, the detrapping coefficient comprises:

[0011] The detrapping coefficient D of the trap electron recovering free from the deep trap e , defined as:

[0012] ;

[0013] The detrapping coefficient D of the trap hole recovering free from the deep trap h , defined as:

[0014] ;

[0015] In the above formula, v is the escape frequency, k is the Boltzmann constant, T is the absolute temperature, U c is the conduction band bottom energy level, U v is the valence band top energy level, U e is the deep trap energy level of the electron, U h is the deep trap energy level of the hole, ΔU tre is the deep trap depth of the electron, ΔU trh is the deep trap depth of the hole.

[0016] Optionally, the diffusion coefficient comprises:

[0017] The electron diffusion coefficient D fe , defined as:

[0018] ;

[0019] The hole diffusion coefficient D fh , defined as:

[0020] ;

[0021] In the above formula, μ e is the electron mobility, μ h is the hole mobility, k is the Boltzmann constant, T is the absolute temperature, and e is the electron charge.

[0022] Optionally, in the step S2, the isothermal relaxation current is fitted by a third-order exponential decay function as follows:

[0023] ;

[0024] wherein I(t) represents the isothermal relaxation current, I0 represents the current steady-state value of the insulation at the steady time, a i is the amplitude coefficient, τ i is the time constant, and e is the natural constant;

[0025] The aging factor is calculated by the following formula:

[0026] ;

[0027] wherein A represents the aging factor, Q(τ3) and Q(τ2) are calculated by the following formula:

[0028] ;

[0029] .

[0030] Optionally, the step of updating the detrapping coefficient based on the aging factor is specifically as follows:

[0031] The detrapping coefficient D e for recovering the trapped electrons from the deep traps to be free is updated as follows:

[0032] ;

[0033] The detrapping coefficient D h for recovering the trapped holes from the deep traps to be free is updated as follows:

[0034] .

[0035] Optionally, in the step S2, the actual carrier mobility includes:

[0036] The actual electron mobility μ eA is calculated by the following formula:

[0037] ;

[0038] The actual hole mobility μ hA is calculated by the following formula:

[0039] ;

[0040] In the above formula, d is the thickness of the insulation sheet, V is the applied voltage, and τ is the transit time.

[0041] Optionally, the step of updating the diffusion coefficient based on the actual carrier mobility is specifically:

[0042] The electron diffusion coefficient D fe is updated as follows:

[0043] ;

[0044] The hole diffusion coefficient D fh is updated as follows:

[0045] .

[0046] Optionally, the method is used for polypropylene insulation space charge simulation.

[0047] The application further provides a cable insulation space charge simulation device based on an aging factor coupling, which comprises:

[0048] A simulation model establishing module is configured to establish a bipolar carrier charge transport model, parameters of the bipolar carrier charge transport model including a detrapping coefficient and a diffusion coefficient;

[0049] An experimental data obtaining module is configured to obtain an aging factor and an actual carrier mobility of a cable insulation sample;

[0050] A simulation model updating module is configured to update the detrapping coefficient of the bipolar carrier charge transport model according to the aging factor, and update the diffusion coefficient of the bipolar carrier charge transport model according to the actual carrier mobility; and the updated simulation model is recorded as an aging factor coupling type insulation charge transport model;

[0051] A simulation calculation module is configured to perform numerical solution on the aging factor coupling type insulation charge transport model in a virtual space, and obtain simulation data of space charge distribution and local electric field change of the cable insulation.

[0052] The application further provides a computer device, which comprises a memory and a processor, the memory stores a computer program, and the processor realizes the above-mentioned cable insulation space charge simulation method based on an aging factor coupling when executing the computer program.

[0053] The application has the following beneficial effects:

[0054] The technical scheme of the application corrects the aging coupling parameter based on experimental data, couples the aging factor and the actual carrier mobility into the traditional double-carrier transport model, eliminates the prediction deviation caused by the traditional model ignoring the aging factor, realizes more accurate simulation of the cable insulation space charge distribution and the local electric field change, can provide theoretical support for cable insulation structure optimization and online diagnosis of the aging state, and helps to improve the safety and operation reliability of power equipment. BRIEF DESCRIPTION OF DRAWINGS

[0055] In order to more clearly illustrate the technical schemes in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0056] Figure 1 The flowchart for some embodiments of the cable insulation space charge simulation method based on the aging factor coupling of the present application is shown in the figure.

[0057] Figure 2 The schematic diagram of the dielectric internal bipolar carrier conduction mechanism is shown in the figure.

[0058] Figure 3 The equivalent circuit diagram of the isothermal relaxation method test system is shown in the figure. DETAILED DESCRIPTION

[0059] In order to make the purposes, features and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the embodiments described below are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0060] The space charge in the cable insulation material is closely related to the aging and degradation of the insulation material, and the coupling mechanism is as follows: in the polymer insulation, electrical aging will introduce trap defects and affect the carrier transport characteristics, the injection and accumulation of space charge will cause local electric field enhancement, thereby accelerating the aging mechanism such as material bond chain damage; research shows that space charge accumulation is a key factor of insulation aging and breakdown, which can increase the aging rate and cause material failure in advance; as the aging degree deepens, the deep trap density in the material increases, more charges are captured and retained, causing more significant local field distortion, which in turn further aggravates material aging, thereby forming a positive feedback and accelerating the degradation of insulation performance.

[0061] Therefore, it is of great significance to couple the aging factor into the traditional double-carrier transport model for accurately simulating the space charge distribution and local electric field change of the cable insulation and scientifically evaluating the aging state of the insulation; based on this, an aging factor coupling-based cable insulation space charge simulation method is provided in the embodiments of the present application.

[0062] The embodiments of the present application are suitable for the space charge simulation of polypropylene insulation; the polypropylene is the most widely used insulation material in the electrical equipment field due to its good insulation performance, heat resistance, chemical stability and mechanical properties; the embodiments of the present application are also suitable for other types of cable insulation materials such as cross-linked polyethylene, polyvinyl chloride, polyurethane, polystyrene and polyimide.

[0063] Referring to Figure 1 Taking the polypropylene insulation as an example, the aging factor coupling-based cable insulation space charge simulation method provided by the embodiments of the present application includes the following steps:

[0064] S1, a bipolar carrier charge transport model is established, and the parameters of the bipolar carrier charge transport model include a detrapping coefficient and a diffusion coefficient.

[0065] The conduction mechanism of the bipolar carrier is as shown in Figure 2 There are four types of charge particles in the bipolar carrier charge transport model: free electrons, free holes, trapped electrons trapped in traps and trapped holes, and the charge conduction process includes three parts: electrode injection of electrons and holes, trap capture and detrapping, and recombination; in the bipolar carrier charge transport model, the charges are injected into the dielectric material from the electrodes by applying a direct current voltage, and the transport process of the charges in the dielectric material can be represented by a continuity equation, a Poisson equation and a conduction equation.

[0066] Continuity equation:

[0067] ;

[0068] Poisson equation:

[0069] ;

[0070] Conduction equation:

[0071] ;

[0072] In the above formulae, denotes the current density in a unit volume of the sample, and denote the charge mobility and the charge density, respectively, denotes the diffusion coefficient, denotes the net space charge density, represents the relative dielectric constant, represents the vacuum dielectric constant, subscript a represents holes or electrons, Represents the source term; the specific description equation of the source term is as follows:

[0073] ;

[0074] ;

[0075] ;

[0076] ;

[0077] Among them, n eμ and n hμ is the density of free electrons and free holes, n et and n ht is the density of trapped electrons and trapped holes, n oet and n oht is the maximum density of electron and hole traps, S0, S1, S2, S3 are recombination coefficients, and B e and B h is the cross-section coefficient of free electrons and free holes captured by deep traps, D e and D h is the detrapping coefficient for trapped electrons and trapped holes to recover from deep traps.

[0078] The escape coefficient includes:

[0079] The release coefficient D of trapped electrons recovering from deep traps e , defined as:

[0080] ;

[0081] The release coefficient D of trapped holes recovering from deep traps h , defined as:

[0082] ;

[0083] In the above formula, v is the escape frequency, k is the Boltzmann constant, T is the absolute temperature, and U is c is the conduction band bottom energy level, U v is the valence band top energy level, U e is the deep trap energy level of electrons, U h is the deep trap energy level of holes, ΔU tre is the electron trap depth, ΔU trh is the deep trap depth of the hole.

[0084] μ e represents electron mobility, μh denotes the hole mobility, and the diffusion coefficient is further calculated, including:

[0085] electron diffusion coefficient D fe , defined as:

[0086] ;

[0087] hole diffusion coefficient D fh , defined as:

[0088] ;

[0089] In the above formula, μ e is the electron mobility, μ h is the hole mobility, k is the Boltzmann constant, T is the absolute temperature, and e is the electron charge.

[0090] S2, sampling the cable insulation, measuring the isothermal relaxation current of the sample to calculate the aging factor of the sample; the actual carrier mobility of the sample is measured by the time-of-flight method.

[0091] The isothermal relaxation current (IRC) experiment is used to obtain the trap energy level distribution and carrier trap dynamic parameters inside the material. The specific steps are as follows: first, a certain direct current field is applied to the sample for polarization precharge, then the electrodes are short-circuited and the decay curve of the relaxation current with time is measured at a constant temperature. The decay current is derived from the release (de-trapping) process of the charges previously captured by the traps, and the amplitude and decay rate directly reflect the number and depth of traps inside the material.

[0092] The isothermal relaxation current of the insulating material is measured by the isothermal relaxation current experiment, so as to understand the defect condition of the insulating material, and the defect condition reflects the aging condition; wherein, the equivalent circuit of the isothermal relaxation current test system refers to Figure 3 In the solid dielectric aging theory, the dielectric can be equivalent to three pairs of parallel resistance and capacitance, representing three polarization processes inside the dielectric, including solid insulator polarization, amorphous and crystal interface polarization, and various defects introduced by aging (such as polarization of metal salt and hydrated ion); based on the theory, the isothermal relaxation current of the dielectric can be fitted by a three-index function: ;

[0093] In the formula, I(t) represents the isothermal relaxation current, I0 represents the current steady-state value of the insulation at the stable time, a i is the amplitude coefficient, τ i is the time constant, and e is the natural constant.

[0094] In order to better study and evaluate the aging condition of the dielectric, an aging factor A is introduced to quantitatively calculate the aging condition of the dielectric:

[0095]

[0096] Among them:

[0097]

[0098]

[0099] The time-of-flight method is used to measure the carrier mobility, and the device structure used in the test is: electrode / insulating sheet / electrode; There is a large potential barrier between the electrode and the insulating sheet, and a voltage is directly applied between the two electrodes, and the current in the circuit is very small. One side of the electrode is transparent, and at the beginning of the test, a single pulse laser with a pulse width in the nanosecond scale is radiated from the transparent electrode side of the sample, and the laser cannot penetrate the sample, but a thin layer of holes and electrons will be generated near the electrode. Taking the test of holes as an example, in this case, the transparent electrode is connected to the positive electrode, and under the action of the electric field, the electrons generated by the laser radiation quickly enter the positive electrode, and the holes move towards the negative electrode. With the movement of the holes, a current will be induced in the external circuit, and the size of the voltage across a known resistor connected in series in the external circuit can be recorded by an oscilloscope, and the current in the circuit can be obtained. When the carriers completely reach the negative electrode, the current in the external circuit disappears. The transient current signal obtained in this way can be used to determine the movement time of the carriers between the two electrodes, which is called the transit time τ. The actual mobility can be obtained according to the following formula:

[0100] The actual electron mobility μ eA is calculated by the following formula:

[0101]

[0102] The actual hole mobility μ hA is calculated by the following formula:

[0103]

[0104] In the above formula, d is the thickness of the insulating sheet, V is the applied voltage, and τ is the transit time.

[0105] S3, update the detrapping coefficient based on the aging factor to obtain the aging coupling corrected detrapping coefficient; update the diffusion coefficient based on the actual carrier mobility to obtain the aging coupling corrected diffusion coefficient; substitute the aging coupling corrected detrapping coefficient and the aging coupling corrected diffusion coefficient into the bipolar carrier charge transport model to obtain the aging factor coupling type insulating charge transport model.

[0106] ​​​​​Specifically, the embodiment of the present application prepares a series of insulation material samples with different aging degrees (through artificial accelerated aging test or from field samples with different service times), which represent multiple stages from the fresh state without aging to severe aging, and the electrical tests are respectively conducted on each sample under the condition that other conditions are consistent, so as to eliminate the influence of stray factors and only investigate the influence of the aging factor on the carrier transport characteristics; for example, in some experiments, the isothermal relaxation current decay of the aged sample is obviously slower, and the steady residual current is larger, which indicates that the deep trap content is increased, and through fitting analysis, it is found that the decay time constant τ of the aged sample is longer than that of the unaged sample, and the trap activation energy ΔU is higher, which indicates that deeper trap energy levels are generated in the material with the deepening of the aging degree, and it is more difficult for charges to be released from the traps; at the same time, aging also leads to the increase of the total density of traps, which is manifested as the increase of the initial value and the stable value of the relaxation current; these quantitative data comprehensively characterize the influence of the aging factor on the trap parameters (depth and density).

[0107] On the basis of the above theory and experimental data rules, the steps of updating the detrapping coefficient based on the aging factor are as follows:

[0108] The detrapping coefficient D for recovering the trap electron from the deep trap to be free e is updated to the following formula:

[0109] ;

[0110] The detrapping coefficient D for recovering the trap hole from the deep trap to be free h is updated to the following formula:

[0111] .

[0112] Similarly, the time-of-flight method is used to measure the carrier mobility of the samples at each aging stage, and the electron / hole mobility data of the samples at each aging stage are obtained, and the experimental results show that with the aggravation of aging, the carrier mobility of the sample shows a downward trend - this is mainly due to the increase of defects in the material, the deepening of traps, and the more frequent capture and scattering of carriers in the migration process; therefore, the actual carrier mobility of the sample is also an important parameter of the aging factor coupled into the bipolar carrier charge transport model.

[0113] On the basis of the above theory and experimental data rules, the steps of updating the diffusion coefficient based on the actual carrier mobility are as follows:

[0114] The electron diffusion coefficient D fe is updated to the following formula:

[0115] ;

[0116] The hole diffusion coefficient Dfh The update is as follows:

[0117] .

[0118] The above aging-coupled detrapping coefficient and diffusion coefficient are substituted into the bipolar carrier transport model to obtain an aging factor coupled insulation charge transport model.

[0119] S4, the aging factor coupled insulation charge transport model is numerically solved to obtain simulation data of the spatial charge distribution and local electric field change of the cable insulation; the process of numerical solution is consistent with the traditional bipolar carrier charge transport model, and the difference of the embodiment of the application lies in that the aging-coupled detrapping coefficient and diffusion coefficient are used.

[0120] The embodiment of the application corrects the aging-coupled parameters based on experimental data, couples the aging factor and the actual carrier mobility into the traditional bipolar carrier transport model, eliminates the prediction deviation caused by ignoring the aging factor in the traditional model, realizes more accurate simulation of the spatial charge distribution and local electric field change of the cable insulation, and provides theoretical support for the optimization of the cable insulation structure and the online diagnosis of the aging state, which helps to improve the safety and operation reliability of the power equipment.

[0121] For example, the following two practical application situations:

[0122] Situation 1: The parameters in the model are dynamically updated by using the relationship between the aging factor A and the changes of electron / hole mobility, trap detrapping coefficient and diffusion coefficient, so as to realize accurate simulation of the spatial charge distribution and electric field change under different aging states; for example, aging can reduce the threshold field strength of spatial charge accumulation, so that it is easier to form trapped charges even under lower field, causing greater field inhomogeneity; the model can reproduce this phenomenon by introducing the influence of the aging factor on the threshold field strength.

[0123] In case 2, the conventional research method obtains the aging factor through the isothermal relaxation current experiment data, and then directly compares through the judgment basis (for example, the standard judgment basis formulated by Germany, Australia, South Korea and other countries) to finally obtain the residual life of the cable insulation. This method can only roughly predict the life of the cable insulation. In the embodiment of the present application, the space charge behavior is taken as the representation of the aging degree based on the aging factor coupling type insulation charge transport model. Specifically, after obtaining the aging factor and the actual carrier mobility of the insulation material sample through experiments, the space charge distribution and the residual local field strength of the insulation material under the working electric field are obtained through simulation, which can be compared with the data at different aging stages to determine the actual aging state of the material. For example, it has been found in the field that the amount of space charge trapped in the dielectric under short circuit conditions is linearly related to the aging time, and corresponds to the linear decrease of the breakdown field strength. Therefore, the space charge accumulation obtained through simulation can quantitatively evaluate the degree of dielectric performance degradation caused by the material aging factor. At the same time, simulation can provide rich aging information (such as the change of the space charge threshold field strength) that cannot be directly obtained by traditional DC voltage resistance and dielectric loss methods, and provide more accurate and rich basis for evaluating the insulation state.

[0124] The present application also provides a cable insulation space charge simulation device based on aging factor coupling. In some embodiments, the device includes a simulation model establishment module, an experimental data acquisition module, a simulation model updating module and a simulation calculation module.

[0125] The simulation model establishment module is used to establish a bipolar carrier charge transport model, and the parameters of the bipolar carrier charge transport model include the detrapping coefficient and the diffusion coefficient.

[0126] The experimental data acquisition module is used to obtain the aging factor and the actual carrier mobility of the cable insulation sample.

[0127] The simulation model updating module is used to update the detrapping coefficient of the bipolar carrier charge transport model according to the aging factor, and update the diffusion coefficient of the bipolar carrier charge transport model according to the actual carrier mobility. The updated simulation model is recorded as the aging factor coupling type insulation charge transport model.

[0128] The simulation calculation module is used to numerically solve the aging factor coupling type insulation charge transport model in a virtual space to obtain the simulation data of the space charge distribution and the local electric field change of the cable insulation.

[0129] The definitions of the parameters in each module and the calculation methods adopted refer to the aforementioned method embodiments, and the technical effects that can be achieved by the aforementioned method embodiments can be achieved by the device, which will not be described here.

[0130] The application further provides a computer device, which comprises a memory and a processor in some embodiments, the memory stores a computer program, and the processor implements the method for simulating space charge in cable insulation based on coupling of aging factors in the foregoing embodiments when executing the computer program; therefore, the computer device can achieve the technical effects of the foregoing method embodiments, which will not be described herein again.

[0131] It can be understood by those skilled in the art that all or part of the processes in the foregoing method embodiments can be completed by instructing relevant hardware through a computer program, and the computer program can be stored in a nonvolatile computer readable storage medium; any reference to the memory, storage, database or other medium used in the embodiments of the application can include at least one of the nonvolatile and volatile memories.

[0132] The foregoing embodiments are only used to illustrate the technical solutions of the application, rather than limit the same; although the application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A cable insulation space charge simulation method based on aging factor coupling, characterized in that: Including steps: S1, establishing a bipolar carrier charge transport model, wherein the parameters of the bipolar carrier charge transport model include a detrapping coefficient and a diffusion coefficient; S2, sampling the cable insulation, measuring the isothermal relaxation current of the sample to calculate the aging factor of the sample; using the time-of-flight method to measure the actual carrier mobility of the sample; S3, updating the detrapping coefficient based on the aging factor, and updating the diffusion coefficient based on the actual carrier mobility, to obtain an aging factor coupled insulating charge transport model; S4, numerically solving the aging factor coupled insulation charge transport model to obtain simulation data of the spatial charge distribution and local electric field changes of the cable insulation.

2. The cable insulation space charge simulation method based on aging factor coupling according to claim 1 is characterized in that: The detrapment coefficient includes: The release coefficient D of trapped electrons recovering from deep traps e , defined as: ； The release coefficient D of trapped holes recovering from deep traps h , defined as: ； In the above formula, v is the escape frequency, k is the Boltzmann constant, T is the absolute temperature, and U is c is the conduction band bottom energy level, U v is the top energy level of the valence band, U e is the deep trap energy level of electrons, U h is the deep trap energy level of the hole, ΔU tre is the electron trap depth, ΔU trh is the deep trap depth of the hole.

3. The cable insulation space charge simulation method based on aging factor coupling according to claim 1 is characterized in that: The diffusion coefficients include: Electron diffusion coefficient D fe , defined as: ； Hole diffusion coefficient D fh , defined as: ； In the above formula, μ e is the electron mobility, μ h is the hole mobility, k is the Boltzmann constant, T is the absolute temperature, and e is the electron charge.

4. The cable insulation space charge simulation method based on aging factor coupling according to claim 1 is characterized in that: In step S2, the isothermal relaxation current is fitted by the following third-order exponential decay function: ； Where, I(t) represents the isothermal relaxation current, I0 represents the steady-state value of the insulation current when it is stable, and a i is the amplitude coefficient, τ i is the time constant, e is the natural constant; The aging factor is calculated by the following formula: ； Where A represents the aging factor, and Q(τ3) and Q(τ2) are calculated by the following formula: ； 。 5. The cable insulation space charge simulation method based on aging factor coupling according to claim 4 is characterized in that: The steps of updating the detrapment coefficient based on the aging factor are specifically as follows: The release coefficient D that frees trapped electrons from deep traps e Update to the following: ； The release coefficient D that frees trapped holes from deep traps h Update to the following: 。 6. The cable insulation space charge simulation method based on aging factor coupling according to claim 3 is characterized in that: In step S2, the actual carrier mobility includes: Actual electron mobility μ eA , calculated by the following formula: ； Actual hole mobility μ hA , calculated by the following formula: ； In the above formula, d is the thickness of the insulating sheet, V is the applied voltage, and τ is the transit time.

7. The cable insulation space charge simulation method based on aging factor coupling according to claim 6 is characterized in that: The step of updating the diffusion coefficient based on the actual carrier mobility is specifically: The electron diffusion coefficient D fe Update to the following: ； The hole diffusion coefficient D fh Update to the following: 。 8. The cable insulation space charge simulation method based on aging factor coupling according to any one of claims 1 to 7, characterized in that: The cable insulation is made of polypropylene.

9. A cable insulation space charge simulation device based on aging factor coupling, characterized in that: include: A simulation model establishment module is used to establish a bipolar carrier charge transport model, wherein the parameters of the bipolar carrier charge transport model include a detrapping coefficient and a diffusion coefficient; Experimental data acquisition module, used to obtain the aging factor and actual carrier mobility of cable insulation samples; A simulation model updating module, configured to update a detrapping coefficient of the bipolar carrier charge transport model according to the aging factor, and to update a diffusion coefficient of the bipolar carrier charge transport model according to the actual carrier mobility; The updated simulation model is recorded as the aging factor coupled insulating charge transport model; The simulation calculation module is used to numerically solve the aging factor coupled insulation charge transport model in a virtual space to obtain simulation data of the spatial charge distribution and local electric field changes of the cable insulation.

10. A computer device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the cable insulation space charge simulation method based on aging factor coupling according to any one of claims 1 to 8 is implemented.

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