Simulation method and device for cable insulation space charge based on coupling of aging factor

Abstract

The application discloses a cable insulation space charge simulation method and device based on an aging factor coupling, and relates to the technical field of electrical engineering; the method comprises the following steps: a bipolar carrier charge transport model is established, and model parameters comprise a detrapping coefficient and a diffusion coefficient; a cable insulation is sampled, isothermal relaxation current of a sample is measured to calculate an aging factor of the sample; actual carrier mobility of the sample is measured by using a time-of-flight method; the detrapping coefficient is updated based on the aging factor, the diffusion coefficient is updated based on the actual carrier mobility, and an aging factor coupling type insulation charge transport model is obtained; the aging factor coupling type insulation charge transport model is numerically solved to obtain simulation data of space charge distribution and local electric field change of the cable insulation. The technical scheme accurately simulates the space charge distribution and the local electric field change of the cable insulation, and can provide scientific evaluation for the aging state of the cable insulation.

Description

Technical Field

[0001] This invention relates to the field of electrical engineering technology, and in particular to a method and apparatus for simulating space charge in cable insulation based on aging factor coupling. Background Technology

[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 constantly increasing, which places higher demands on the withstand voltage and long-term stability of insulating materials. One of the main factors that has long restricted the development of polymer-insulated DC cables is the dendritic breakdown caused by the accumulation of space charge in the polymer solid dielectric under DC high voltage. Therefore, establishing an insulation charge transport model and predicting the life of insulating materials is of great significance for improving the electric field distribution inside the cable, optimizing the cable structure design, improving the insulation performance of DC cables, and extending the cable life.

[0003] In existing research, the bipolar carrier charge transport model proposed by J.M.A. Lison and R.M. Hill can dynamically simulate the migration, diffusion, trapping, and detrapping of space charge. After attempts and improvements by different scholars, a theoretical space charge distribution close to the measurement results can be obtained under the condition of a flat plate electrode. However, a bipolar carrier transport model under aging conditions, which is extremely important and closer to reality, has not yet been reported, and is still a blank in the current research field of polymer insulation. During long-term operation, cable insulation materials gradually age under the combined effects of electrical, thermal, mechanical stress and environmental factors, and their physical, chemical and electrical properties gradually deteriorate, thereby increasing the risk of equipment failure and safety hazards. Therefore, it is urgent to propose a bipolar carrier transport model that is more in line with the actual aging conditions of cable insulation, so as to accurately simulate the space charge distribution and local electric field changes of cable insulation, and provide a more scientific assessment of the aging state of insulation. Summary of the Invention

[0004] This invention provides a method for simulating the space charge of cable insulation based on aging factor coupling, which aims to accurately simulate the space charge distribution and local electric field changes of cable insulation and provide a scientific assessment of the aging state of the insulation.

[0005] The cable insulation space charge simulation method based on aging factor coupling provided by this invention includes the following steps:

[0006] S1, Establish a bipolar carrier charge transport model, wherein the parameters of the bipolar carrier charge transport model include the trapping coefficient and the diffusion coefficient;

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

[0008] S3, update the de-trapping coefficient based on the aging factor, and update the diffusion coefficient based on the actual carrier mobility to obtain the aging factor coupled insulating charge transport model;

[0009] S4. Numerical solution is performed on the aging factor coupled insulation charge transport model to obtain simulation data of space charge distribution and local electric field changes in cable insulation.

[0010] Optionally, the de-trapping coefficient includes:

[0011] The escape coefficient D of a trapped electron recovering freedom from a deep trap. e Defined as:

[0012] ;

[0013] The escape coefficient D of a trap cavity regaining freedom from a deep trap. h Defined as:

[0014] ;

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

[0016] Optionally, the diffusion coefficient includes:

[0017] Electron diffusion coefficient D fe Defined as:

[0018] ;

[0019] Hole diffusion coefficient D fh Defined as:

[0020] ;

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

[0022] Optionally, in step S2, the isothermal relaxation current is fitted using the following third-order exponential decay function:

[0023] ;

[0024] In the formula, I(t) represents the isothermal relaxation current, I0 represents the steady-state current value of the insulation when it is stable, and a i τ is the amplitude coefficient. i Let e ​​be the time constant and e be the natural constant.

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

[0026] ;

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

[0028] ;

[0029] .

[0030] Optionally, the step of updating the deterioration coefficient based on the aging factor specifically includes:

[0031] The escape coefficient D that frees trapped electrons from deep traps e Updated to the following formula:

[0032] ;

[0033] The escape coefficient D for freeing a hole from a deep trap. h Updated to the following formula:

[0034] .

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

[0036] Actual electron mobility μ eA It can be calculated using the following formula:

[0037] ;

[0038] Actual hole mobility μ hA It can be calculated using the following formula:

[0039] ;

[0040] In the above formula, d is the thickness of the insulating 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 specifically includes:

[0042] The electron diffusion coefficient D fe Updated to the following formula:

[0043] ;

[0044] The hole diffusion coefficient D fh Updated to the following formula:

[0045] .

[0046] Optionally, the method provided by the present invention is used for space charge simulation of polypropylene insulation.

[0047] The present invention also provides a cable insulation space charge simulation device based on aging factor coupling, the device comprising:

[0048] The simulation model building module is used to build a bipolar carrier charge transport model, the parameters of which include the trapping coefficient and the diffusion coefficient.

[0049] The experimental data acquisition module is used to obtain the aging factor and actual carrier mobility of cable insulation samples.

[0050] The simulation model update module is used to update the de-trapping coefficient of the bipolar carrier charge transport model according to the aging factor, and to update the diffusion coefficient of the bipolar carrier charge transport model according to the actual carrier mobility; the updated simulation model is denoted as the aging factor coupled insulating charge transport model.

[0051] The simulation calculation module is used to numerically solve the aging factor coupled insulation charge transport model in virtual space to obtain simulation data of the space charge distribution and local electric field changes of the cable insulation.

[0052] The present invention also provides a computer device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method for simulating space charge in cable insulation based on aging factor coupling.

[0053] The present invention has the following beneficial effects:

[0054] The technical solution of this invention is based on aging coupling parameters corrected by experimental data. It couples the aging factor and the actual carrier mobility into the traditional dual carrier transport model, eliminating the prediction bias caused by neglecting aging factors in the traditional model. This enables a more accurate simulation of the space charge distribution and local electric field changes in cable insulation, providing theoretical support for the optimization of cable insulation structure and online diagnosis of aging conditions, and helping to improve the safety and operational reliability of power equipment. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 The following are flowcharts of some embodiments of the cable insulation space charge simulation method based on aging factor coupling of the present invention;

[0057] Figure 2 A schematic diagram of the bipolar carrier conduction mechanism inside a medium;

[0058] Figure 3 This is the equivalent circuit diagram of the isothermal relaxation method test system. Detailed Implementation

[0059] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0060] The space charge situation in cable insulation materials is closely related to the aging and deterioration of the insulation materials. The coupling mechanism is as follows: In polymer insulation, electrical aging introduces trap defects and affects the carrier transport characteristics. The injection and accumulation of space charge leads to the enhancement of the local electric field, thereby accelerating the aging mechanism such as the destruction of material bonds. Studies have shown that space charge accumulation is a key factor in insulation aging and breakdown, which increases the aging rate and accelerates material failure. As the aging degree deepens, the density of deep traps in the material increases, and more charges are captured and retained, resulting in a significant increase in local field distortion. This distortion, in turn, further aggravates material aging, thus forming a positive feedback loop and accelerating the degradation of insulation performance.

[0061] Therefore, coupling the aging factor into the traditional dual-carrier transport model is of great significance for accurately simulating the space charge distribution and local electric field changes of cable insulation, as well as scientifically assessing the aging state of the insulation. Based on this, this invention proposes a cable insulation space charge simulation method based on aging factor coupling.

[0062] This invention is applicable to space charge simulation of polypropylene insulation. Polypropylene is the most widely used insulation material in the field of electrical equipment due to its excellent insulation properties, heat resistance, chemical stability and mechanical properties. This invention is also applicable to other types of cable insulation materials such as cross-linked polyethylene, polyvinyl chloride, polyurethane, polystyrene, polyimide, etc.

[0063] See Figure 1 Taking polypropylene insulation as an example, the cable insulation space charge simulation method based on aging factor coupling provided in this embodiment of the invention includes the following steps:

[0064] S1. Establish a bipolar carrier charge transport model. The parameters of the bipolar carrier charge transport model include the trapping coefficient and the diffusion coefficient.

[0065] Among them, the conduction mechanism of bipolar carriers is as follows: Figure 2 As shown, the bipolar carrier charge transport model contains four types of charged particles: free electrons, free holes, trapped electrons and trapped holes trapped inside traps. The charge conduction process includes three parts: electrode injection of electrons and holes, trap capture and detachment, and recombination. In the bipolar carrier charge transport model, by applying a DC voltage, charge is injected into the dielectric material through electrodes. The charge transport process in the dielectric can be represented by the continuity equation, Poisson's equation, and conduction equation.

[0066] Continuity equation:

[0067] ;

[0068] Poisson equation:

[0069] ;

[0070] Conduction equation:

[0071] ;

[0072] In the above formula, This represents the current density per unit volume of the sample. and These represent charge mobility and charge density, respectively. Indicates the diffusion coefficient. Represents net space charge density. Represents the relative permittivity. This represents the vacuum permittivity, and the subscript 'a' indicates a hole or electron. The source term is represented by the equation described below:

[0073] ;

[0074] ;

[0075] ;

[0076] ;

[0077] Where, n eμ and n hμ n represents the density of free electrons and free holes. et and n ht n represents the density of trapped electrons and trapped holes. oet and n oht It represents the maximum density of electron and hole traps, where S0, S1, S2, and S3 are recombination coefficients, and B... e and B h D is the cross-sectional factor for the trapping of free electrons and free holes by deep traps. e and D h The escape coefficient is the factor by which trapped electrons and trapped holes regain freedom from deep traps.

[0078] The de-trapping coefficient includes:

[0079] The escape coefficient D of a trapped electron recovering freedom from a deep trap. e Defined as:

[0080] ;

[0081] The escape coefficient D of a trap cavity regaining freedom from a deep trap. h Defined as:

[0082] ;

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

[0084] Using μ respectively e μ represents electron mobility.h This represents the hole mobility, and the diffusion coefficient is further calculated. The diffusion coefficient includes:

[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 μ represents electron mobility. h denoted as hole mobility, k as Boltzmann constant, T as absolute temperature, and e as electron charge.

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

[0091] The energy level distribution of traps and the dynamic parameters of carrier traps inside the material are obtained by isothermal relaxation current (IRC) experiments. The specific steps are as follows: First, a certain DC electric field is applied to the sample for polarization pre-charging. Then, the electrode is short-circuited and the decay curve of its relaxation current over time is measured at a constant temperature. This decay current comes from the release (de-trapping) process of the charge previously trapped. Its amplitude and decay rate directly reflect the number and depth of traps inside the material.

[0092] Measuring the isothermal relaxation current of insulating materials through isothermal relaxation current experiments can reveal the defects within the material, which reflect the aging process. The equivalent circuit of the isothermal relaxation current testing system is described in [reference needed]. Figure 3 In the aging theory of solid dielectrics, the dielectric can be equivalent to three pairs of parallel resistors and capacitors, representing three polarization processes within the dielectric: solid insulator polarization, amorphous-crystalline interface polarization, and various defects introduced by aging (such as polarization by metal salts and hydrated ions). Based on this theory, the isothermal relaxation current of the dielectric can be fitted using a three-exponential function: ;

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

[0094] To better study and evaluate the aging of dielectrics, an aging factor A is introduced to quantitatively calculate the aging status of the dielectric:

[0095] ;

[0096] in:

[0097] ;

[0098] .

[0099] The time-of-flight method is used to measure carrier mobility. 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. A voltage is directly applied between the two electrodes, and the current in the circuit is very small. One electrode is transparent. At the beginning of the test, a single-pulse laser with a pulse width on the nanosecond scale is used to irradiate the sample from the transparent electrode side. The laser cannot penetrate the sample, but it will generate a thin layer of holes and electrons near the electrode. Taking the hole test as an example, in this case, the transparent electrode is connected to the positive electrode. Under the influence of the electric field, the electrons generated by the laser radiation quickly enter the positive electrode, while the holes move towards the negative electrode. As the holes move, a current is induced in the external circuit. The current in the circuit can be obtained by recording the voltage across a known resistor connected in series in the external circuit with an oscilloscope. When the carriers have completely reached the negative electrode, the current in the external circuit disappears. The transient current signal obtained in this way can be used to determine the time it takes for the carriers to move between the two electrodes. This time is called the transit time τ. The actual mobility can be obtained according to the following formula:

[0100] Actual electron mobility μ eA It can be calculated using the following formula:

[0101] ;

[0102] Actual hole mobility μ hA It can be calculated using 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. Based on the aging factor, update the de-trapping coefficient to obtain the aging coupling correction de-trapping coefficient; based on the actual carrier mobility, update the diffusion coefficient to obtain the aging coupling correction diffusion coefficient; substitute the aging coupling correction de-trapping coefficient and the aging coupling correction diffusion coefficient into the bipolar carrier charge transport model to obtain the aging factor coupled insulating charge transport model.

[0106] Specifically, embodiments of the present invention prepare a series of insulating material samples with different aging degrees (through artificial accelerated aging tests or field samples taken from different service times). These samples represent multiple stages from unaged fresh state to severely aged state. Under the condition that other factors are kept consistent, electrical tests are performed on each sample separately to eliminate the influence of stray factors and only examine the effect of aging factor on charge carrier transport characteristics. For example, in some experiments, the isothermal relaxation current decay of aged samples is significantly slower, and the steady residual current is larger, indicating an increase in deep trap content. Through fitting analysis, it was found that aged samples have a longer decay time constant τ than unaged samples, resulting in a higher trap activation energy ΔU. This indicates that as the degree of aging increases, deeper trap energy levels are generated inside the material, and it is more difficult for charges to be released from the traps. At the same time, aging also leads to an increase in the total trap density, which is manifested in the increase of the initial and stable values ​​of the relaxation current. These quantitative data comprehensively characterize the influence of aging factor on trap parameters (depth and density).

[0107] Based on the above theoretical and experimental data patterns, the specific steps for updating the deterioration coefficient based on aging factors are as follows:

[0108] The escape coefficient D that frees trapped electrons from deep traps e Updated to the following formula:

[0109] ;

[0110] The escape coefficient D for freeing a hole from a deep trap. h Updated to the following formula:

[0111] .

[0112] Similarly, the carrier mobility of samples at each aging stage was determined using the time-of-flight method, and the electron / hole mobility data of samples at each aging stage were obtained. The experimental results show that the carrier mobility of the samples decreases as aging intensifies. This is mainly due to the increase in internal defects and the deepening of traps in the material, which causes carriers to be captured and scattered more frequently during migration. Therefore, the actual carrier mobility of the samples is also an important parameter that aging factors are coupled into the bipolar carrier charge transport model.

[0113] Based on the above theoretical and experimental data patterns, the specific steps for updating the diffusion coefficient based on the actual carrier mobility are as follows:

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

[0115] ;

[0116] The hole diffusion coefficient Dfh Updated to the following formula:

[0117] .

[0118] Substituting the de-trapping coefficient and diffusion coefficient after aging coupling into the bipolar carrier transport model, we obtain the aging factor coupled insulating charge transport model.

[0119] S4. Numerical solution is performed on the aging factor coupled insulation charge transport model to obtain simulation data of space charge distribution and local electric field changes in cable insulation. The numerical solution process is consistent with the traditional bipolar carrier charge transport model. The difference in this embodiment is that the de-trapping coefficient and diffusion coefficient after aging coupling are used.

[0120] The embodiments of this invention use aging coupling parameters corrected based on experimental data to couple the aging factor and the actual carrier mobility into the traditional dual-carrier transport model. This eliminates the prediction bias caused by neglecting aging factors in the traditional model, and achieves a more accurate simulation of the space charge distribution and local electric field changes in cable insulation. It can provide theoretical support for the optimization of cable insulation structure and online diagnosis of aging status, and help improve the safety and operational reliability of power equipment.

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

[0122] In scenario 1, the model dynamically updates parameters by utilizing the relationship between the aging factor A and changes in electron / hole mobility, trapping coefficient, and diffusion coefficient, thereby achieving accurate simulation of space charge distribution and electric field changes under different aging states. For example, aging reduces the threshold field strength for space charge accumulation, making it easier to form stagnant charges even at lower fields, resulting in greater field inhomogeneity. The model can reproduce this phenomenon through simulation by introducing the influence of the aging factor on the threshold field strength.

[0123] Scenario 2: Traditional research methods determine the aging factor using isothermal relaxation current experimental data and then directly compare it with judgment criteria (such as those established by Germany, Australia, and South Korea) to ultimately determine the remaining lifespan of the cable insulation. This method can only provide a rough estimate of the cable insulation's lifespan. In contrast, this invention is based on an aging factor-coupled insulation charge transport model, which uses space charge behavior as a characterization of aging. Specifically, after obtaining the aging factor and actual carrier mobility of the insulation material sample experimentally, the space charge distribution of the insulation material under the working electric field is obtained through simulation. The residual local electric field strength can be compared with data from different aging stages to determine the current actual aging state of the material. For example, research in this field has found that the amount of residual space charge in the dielectric under short-circuit conditions is linearly related to aging time and corresponds to a linear decrease in breakdown field strength. Therefore, the accumulated space charge obtained through simulation can quantitatively assess the degree of dielectric performance degradation caused by material aging factors. At the same time, simulation can provide rich aging information (such as changes in space charge threshold field strength) that cannot be directly obtained by traditional methods such as DC withstand voltage and dielectric loss, providing a more accurate and richer basis for assessing insulation status.

[0124] The present invention 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 update module, and a simulation calculation module.

[0125] The simulation model building module is used to build a bipolar carrier charge transport model. The parameters of the bipolar carrier charge transport model include the trapping coefficient and the diffusion coefficient.

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

[0127] The simulation model update module is used to update the detrapping coefficient of the bipolar carrier charge transport model according to the aging factor, and to update the diffusion coefficient of the bipolar carrier charge transport model according to the actual carrier mobility; the updated simulation model is denoted as the aging factor coupled insulating charge transport model.

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

[0129] The definitions of parameters in each module and the calculation methods used are as described in the aforementioned method embodiments. The device can achieve all the technical effects that can be achieved in the aforementioned method embodiments, and will not be elaborated here.

[0130] The present invention also provides a computer device. In some embodiments, the computer device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the cable insulation space charge simulation method based on aging factor coupling in the foregoing embodiments. Therefore, the computer device can achieve all the technical effects that can be achieved by the foregoing method embodiments, and will not be repeated here.

[0131] Those skilled in the art will understand that all or part of the processes in the foregoing method embodiments can be implemented by a computer program instructing related hardware, and the computer program can be stored in a non-volatile computer-readable storage medium; any reference to memory, storage, database or other media used in the embodiments of the present invention may include at least one of non-volatile and volatile memory.

[0132] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for simulating space charge in cable insulation based on aging factor coupling, characterized in that, Including the following steps: S1, Establish a bipolar carrier charge transport model, wherein the parameters of the bipolar carrier charge transport model include the trapping coefficient and the diffusion coefficient; S2, sample the cable insulation, measure the isothermal relaxation current of the sample to calculate the aging factor of the sample; use the time-of-flight method to measure the actual carrier mobility of the sample; S3, update the de-trapping coefficient based on the aging factor, and update the diffusion coefficient based on the actual carrier mobility to obtain the aging factor coupled insulating charge transport model; S4, Numerical solution is performed on the aging factor coupled insulation charge transport model to obtain simulation data of space charge distribution and local electric field changes in cable insulation; Specifically, the step of updating the deterioration coefficient based on the aging factor is as follows: The escape coefficient D that frees trapped electrons from deep traps e Updated to the following formula: ； The escape coefficient D for freeing a hole from a deep trap. h Updated to the following formula: ； The specific steps for updating the diffusion coefficient based on the actual carrier mobility are as follows: The electron diffusion coefficient D fe Updated to the following formula: ； The hole diffusion coefficient D fh Updated to the following formula: ； In the above formulas, v is the escape frequency, k is the Boltzmann constant, T is the absolute temperature, and ΔU is the value of ΔU. tre For the depth of the electron trap, ΔU trh Let A be the depth of the hole trap, A be the aging factor, e be the electron charge, and μ be the depth of the hole trap. eA μ represents the actual electron mobility. hA This represents the actual hole mobility.

2. The method for simulating cable insulation space charge based on aging factor coupling according to claim 1, characterized in that, In step S1, the de-trapping coefficient includes: The escape coefficient D of a trapped electron recovering freedom from a deep trap. e Defined as: ； The escape coefficient D of a trap cavity as it recovers freedom from a deep trap. h Defined as: ； In the above formulas, v is the escape frequency, k is the Boltzmann constant, T is the absolute temperature, and U is the absolute temperature. c U is the bottom energy level of the conduction band. v U is the top energy level of the valence band. e For the deep trap energy level of electrons, U h For the deep trap energy level of a hole, ΔU tre For the depth of the electron trap, ΔU trh The depth of the deep trap is the cavity.

3. The cable insulation space charge simulation method based on aging factor coupling according to claim 1, characterized in that, In step S1, the diffusion coefficient includes: Electron diffusion coefficient D fe Defined as: ； Hole diffusion coefficient D fh Defined as: ； In the above formula, μ e μ represents electron mobility. h denoted as hole mobility, k as Boltzmann constant, T as absolute temperature, and e as electron charge.

4. The method for simulating cable insulation space charge based on aging factor coupling according to claim 1, characterized in that, In step S2, the isothermal relaxation current is fitted using the following third-order exponential decay function: ； In the formula, I(t) represents the isothermal relaxation current, I0 represents the steady-state current value of the insulation when it is in a steady state, and a i τ is the amplitude coefficient. i Let e ​​be the time constant and e be the natural constant. The aging factor is calculated using the following formula: ； In the formula, A represents the aging factor, and Q(τ3) and Q(τ2) are calculated using the following formula: ； 。 5. The cable insulation space charge simulation method based on aging factor coupling according to claim 3, characterized in that, In step S2, the actual carrier mobility includes: Actual electron mobility μ eA It can be calculated using the following formula: ； Actual hole mobility μ hA It can be calculated using 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.

6. The method for simulating space charge in cable insulation based on aging factor coupling according to any one of claims 1-5, characterized in that, The cable insulation is made of polypropylene.

7. A cable insulation space charge simulation device based on aging factor coupling, characterized in that, include: The simulation model building module is used to build a bipolar carrier charge transport model, the parameters of which include the trapping coefficient and the diffusion coefficient. The experimental data acquisition module is used to obtain the aging factor and actual carrier mobility of cable insulation samples. The simulation model update module is used to update the de-trapping coefficient of the bipolar carrier charge transport model according to the aging factor, and to update the diffusion coefficient of the bipolar carrier charge transport model according to the actual carrier mobility. The updated simulation model is denoted 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 virtual space to obtain simulation data of the space charge distribution and local electric field changes of the cable insulation. Specifically, updating the de-trapping coefficient of the bipolar carrier charge transport model based on the aging factor includes: The escape coefficient D that frees trapped electrons from deep traps e Updated to the following formula: ； The escape coefficient D for freeing a hole from a deep trap. h Updated to the following formula: ； Updating the diffusion coefficient of the bipolar carrier charge transport model based on the actual carrier mobility specifically includes: The electron diffusion coefficient D fe Updated to the following formula: ； The hole diffusion coefficient D fh Updated to the following formula: ； In the above formulas, v is the escape frequency, k is the Boltzmann constant, T is the absolute temperature, and ΔU is the value of ΔU. tre For the depth of the electron trap, ΔU trh Let A be the depth of the hole trap, A be the aging factor, e be the electron charge, and μ be the depth of the hole trap. eA μ represents the actual electron mobility. hA This represents the actual hole mobility.

8. A computer device, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the cable insulation space charge simulation method based on aging factor coupling as described in any one of claims 1-6.

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