Insulating material dielectric strength evaluation method and system based on trap level

Abstract

The invention discloses an insulating material dielectric strength evaluation method and system based on a trap level, belongs to the technical field of electrical equipment and electrical engineering, and is used for accurately evaluating the dielectric strength of an insulating material. The carrier mobility is calculated by collecting depolarization charge quantity attenuation curves of the insulating material after different polarization electric fields, the influence of the electric fields is corrected by adopting a Pole-Frenkel law, and trap level distribution of the insulating material under the different polarization electric fields is obtained. Through exponential decay function fitting, the influence of an electric field on a trap level is extrapolated to a higher electric field range, a corresponding limit trap level under a critical electric field is obtained, and a relation function with direct current breakdown field strength is established, so that the dielectric strength of the insulating material is accurately evaluated through the limit trap level.

Description

Technical Field

[0001] This invention belongs to the field of electrical equipment and electrical engineering technology, specifically relating to a method and system for evaluating the dielectric strength of insulating materials based on trap energy levels. Background Technology

[0002] Dielectric strength is a key indicator for measuring the ability of insulating materials to withstand high voltages without dielectric breakdown, and it is also one of the most important parameters for evaluating their insulation performance. In the field of electrical engineering, the research and development of high-dielectric-strength materials has always been a key focus, leading to the development of various methods for evaluating the dielectric strength of materials. For example, conductivity and dielectric loss, as key dielectric performance parameters, can reflect the dielectric strength characteristics of insulating materials to a certain extent. However, due to limitations in testing conditions, conventional methods often cannot be used to measure dielectric strength at high electric fields close to breakdown. Therefore, the obtained test data usually only represent the dielectric performance of the material under a specific applied electric field, making it difficult to establish a direct and effective correspondence with the actual dielectric strength of the material at high electric fields or even near breakdown, thus hindering further research and development of high-dielectric-strength materials.

[0003] Trapping characteristics are closely related to dielectric strength. The trap center can capture charge carriers migrating under an external electric field; the deeper the trap energy level, the more difficult it is for charge carriers to escape. When charge carriers are trapped in deep traps, their residence time far exceeds their lifetime, which significantly affects their migration behavior and ultimately has a significant impact on the dielectric strength of the insulating material. Therefore, the trapping characteristics of insulating materials can serve as an effective basis for evaluating their dielectric strength. Surface potential decay (SPD) and thermally stimulated current (TSC) methods are commonly used trap characterization techniques. They obtain the trap energy level distribution of the surface and bulk insulating materials under different polarization electric fields by applying polarization to the sample for a certain period and then collecting depolarization curves. However, the trap energy level distribution of the insulating material under different polarization electric fields varies under different polarization times or voltages, making it difficult to accurately extract material trap information and thus preventing the most accurate evaluation of the dielectric strength of the insulating material through trap characteristics. Summary of the Invention

[0004] This invention provides a method and system for evaluating the dielectric strength of insulating materials based on trap energy levels, in order to solve the technical problem in the prior art of failing to extract intrinsic trap parameters of insulating materials in order to establish the relationship between intrinsic trap parameters and dielectric strength.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for evaluating the dielectric strength of insulating materials based on trap energy levels includes the following steps: Obtain the depolarization charge decay curve of the insulating material and calculate the carrier mobility. μ(t) ; Based on carrier mobility μ(t) By correcting for the influence of the electric field using the Poole–Frenkel law, the trap energy level distribution of the insulating material under different polarization electric fields was obtained. ; Trapping energy level distribution under different polarization electric fields of insulating materials By fitting the exponential decay function, the limiting trap level under the critical electric field is obtained, and the relationship curve between the limiting trap level under the critical electric field and the DC breakdown field strength is established.

[0006] The specific steps for obtaining the depolarization charge decay curve of the insulating material are: applying a polarization electric field to the insulating material. E The material is polarized at 0 and then depolarized. The depolarization charge decay curve of the insulating material is collected.

[0007] The polarization of the insulating material specifically involves: DCIC- Q (t) The test system outputs voltage to the insulating material for polarization. The polarization voltage is set to 1~100 kV / mm, and the polarization time is 60~6000 s. DCIC- Q (t) The device sampling step size is 1~5 s; where depolarization specifically refers to a depolarization time of 100~10000 s, DCIC- Q (t) The sampling step size of the device is 1~5 s.

[0008] Based on the depolarization charge decay curve of the insulating material, the ratio of charge to the volume of the insulating material is obtained, and then the carrier mobility is calculated. μ(t) Carrier mobility μ(t) The calculation formula is as follows:

[0009] in, Charge density is the ratio of charge to the volume of the insulating material. The vacuum permittivity, is the relative permittivity.

[0010] Based on carrier mobility μ(t) By correcting for the influence of the electric field using the Poole-Frenkel law, the trap energy level distribution of the insulating material under different polarization electric fields was obtained. The median It can characterize the trap energy level of insulating materials.

[0011] The trap energy level distribution of the insulating material under different polarized electric fields The calculation formula is as follows:

[0012] in, It is Boltzmann's constant. It is thermodynamic temperature. It is the average distance of the local states. It is the escape frequency. It is the amount of electron charge. It is a polarized electric field.

[0013] Trapping energy level distribution under different polarization electric fields of insulating materials The polarization electric field is fitted by an exponential decay function. E With trap energy level The relationship between them, and the fitting relationship, are as follows:

[0014] in, The average trap energy level of the insulating material under a non-polarized electric field. The amplitude of the trap level vibration. The characteristic electric field is denoted as .

[0015] When fitting an exponential decay function, the fitting process ends when the error between the fitted value and the experimental value is less than 1%.

[0016] Based on polarized electric field E With trap energy level By extrapolating the polarization electric field, the trap energy levels of the insulating material under the critical electric field are obtained. Under the critical electric field, the field-assisted deep traps reach saturation, and the corresponding saturation trap energy level is the limiting value of the material, i.e., the limiting trap energy level under the critical electric field. The formula for the limiting trap energy level under the critical electric field is as follows: .

[0017] A dielectric strength evaluation system for insulating materials based on trap energy levels includes a mobility calculation module, a trap energy level distribution calculation module, and a relationship fitting module; The mobility calculation module is used to obtain the depolarization charge decay curve of the insulating material and calculate the carrier mobility. μ(t) ; The trap energy level distribution calculation module is used to calculate based on carrier mobility. μ(t) By correcting for the influence of the electric field using the Poole–Frenkel law, the trap energy level distribution of the insulating material under different polarization electric fields was obtained. ; The relationship fitting module is based on the trap energy level distribution of the insulating material under different polarization electric fields. By fitting the exponential decay function, the limiting trap level under the critical electric field is obtained, and the relationship curve between the limiting trap level under the critical electric field and the DC breakdown field strength is established.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for evaluating the dielectric strength of insulating materials based on trap energy levels. It introduces the Poole-Frenkel law to correct for the influence of the electric field, avoiding interference from the external electric field on carrier transport characteristics. Through the correction effect of this law, the interference of the external electric field on carrier mobility and the distribution of trap energy levels under different polarization electric fields of the insulating material can be effectively eliminated. This makes the final obtained trap energy level distribution of the insulating material under different polarization electric fields closer to the intrinsic state of the insulating material, laying a precise foundation for establishing the correlation between trap parameters and dielectric strength, and improving the scientific rigor of the entire evaluation system from the source.

[0019] Furthermore, this invention fits the relationship between the polarization electric field and the trap energy level using an exponential decay function, and obtains the limiting trap energy level under the critical electric field by extrapolating the polarization electric field. Then, it establishes a relationship curve between this limiting trap energy level and the DC breakdown field strength. This process breaks down the disconnect between microscopic parameters and macroscopic performance, allowing two previously difficult-to-correlate properties to form a clear correspondence. This enables dielectric strength assessment to delve into the microscopic essence of materials, moving beyond the observation of macroscopic phenomena and providing more profound technical support for dielectric strength assessment.

[0020] Furthermore, this invention is based on a standardized DCIC-Q(t) testing system. From setting polarization and depolarization test parameters to calculating carrier mobility, and then to deriving and fitting the trap energy level distribution of insulating materials under different polarization electric fields, each step has a clear logical chain and operating procedures. This standardized process design can effectively reduce the interference of human operation on the results, ensuring good consistency of evaluation results obtained by different operators in different testing scenarios, significantly improving the reliability and repeatability of the evaluation results, and reducing the uncertainty in the application of the technology.

[0021] Furthermore, by adjusting the polarization electric field, the trap energy level distribution of different insulating materials under different polarization electric fields can be characterized. This eliminates the need to reconstruct the test system for specific materials; simply setting the polarization electric field range according to the material properties is sufficient to extract intrinsic trap parameters and assess dielectric strength for various insulating materials. This flexibility not only expands the applicability of the technology but also lowers the barrier to entry for its application in different material fields. It can meet the needs of multiple scenarios, such as insulating material R&D screening and aging status assessment, thus enhancing the practical value of the technology.

[0022] Furthermore, during the fitting process of the exponential decay function, the fitting is explicitly set to end only when the error between the fitted value and the experimental value is less than 1%. This strict precision control ensures that key parameters such as the limiting trap energy level obtained through fitting have extremely high accuracy. As the core medium for establishing the correlation with the DC breakdown field strength, the accuracy of the limiting trap energy level directly affects the accuracy of subsequent dielectric strength assessment. By ensuring the accuracy of key parameters, this invention enables the final dielectric strength assessment results to better reflect the actual performance of the material, providing a more reliable basis for the performance optimization and quality control of insulating materials. Attached Figure Description

[0023] Figure 1 The carrier mobility curves of insulating material A1 in this embodiment of the invention are shown under four polarization electric fields of 10 kV / mm, 20 kV / mm, 40 kV / mm and 70 kV / mm. Figure 2 The diagram shows the trap energy level distribution of insulating material A1 under different polarization electric fields of 20~70 kV / mm in the embodiments of the present invention. Figure 3 The polarization electric field of insulating material A1 in the embodiments of the present invention E and trap energy level U ( E The relationship curve; Figure 4 The limiting energy levels and DC breakdown field strengths of different insulating materials in the embodiments of the present invention are shown. E bd Relationship curve; Figure 5 This is a schematic flowchart of a method for evaluating the dielectric strength of insulating materials based on trap energy levels, as described in an embodiment of the present invention. Detailed Implementation

[0024] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0025] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] Example 1 This embodiment proposes a method for evaluating the dielectric strength of insulating materials based on trap energy levels, such as... Figure 5 As shown, it includes the following steps: Obtain the depolarization charge decay curve of the insulating material and calculate the carrier mobility. μ(t) ; Based on carrier mobility μ(t)By correcting for the influence of the electric field using the Poole–Frenkel law, the trap energy level distribution of the insulating material under different polarization electric fields was obtained. ; Trapping energy level distribution under different polarization electric fields of insulating materials By fitting an exponential decay function, the influence of the electric field on the trap energy level is extrapolated to a higher electric field range to obtain the limiting trap energy level under the critical electric field. A relationship curve between the limiting trap energy level under the critical electric field and the DC breakdown field strength is established. Based on the obtained relationship curve between the limiting trap energy level under the critical electric field and the DC breakdown field strength, it is only necessary to measure the limiting trap energy level of the insulating material to be evaluated. Its DC dielectric strength can be directly obtained through this relationship curve, thus achieving rapid and accurate evaluation. Specifically, a DCIC-Q(t) testing system outputs a voltage to the insulating material to apply a polarized electric field to it. E Polarization is performed at 0, followed by depolarization. The depolarization charge decay curve of the insulating material is collected, and the carrier mobility is calculated. m (t The Poole-Frenkel law was used to correct for the influence of the electric field, and the trap energy levels of the insulating material under the initial polarization electric field were obtained. U ( E 0). By changing the polarization electric field and repeating the aforementioned steps, the trap energy levels of the insulating material under different polarization electric fields can be obtained. U ( E This allows us to obtain the trap energy level distribution of the insulating material under different polarization electric fields. .

[0027] In this embodiment, the insulation material thickness is 10~2000 μm, preferably 100~500 μm. Before testing, the insulation material should be dried in a vacuum oven to remove moisture and other impurities. Before polarization, it should be cleaned with a sterile cotton cloth soaked in alcohol. Subsequently, the insulation material is placed in a three-electrode system, and a voltage is output to the insulation material to polarize it. The polarization voltage is set to 1~100 kV / mm, and the polarization time is 60~6000 s. DCIC- Q (t) The sampling step size of the device is 1~5 s. After polarization is completed, the voltage is removed, the depolarization time is 100~10000 s, and the sampling step size is 1~5 s, thus obtaining the depolarization charge decay curve of the insulating material. Q atten ( t ).

[0028] Based on the depolarization charge decay curve of the insulating material, the ratio of charge to the volume of the insulating material is obtained, and then the carrier mobility is calculated. μ(t) Carrier mobility μ(t) The calculation formula is as follows:

[0029] in, Charge density is the ratio of charge to the volume of the insulating material. The vacuum permittivity is 8.854 × 10⁻⁶, which is 8.854 × 10⁻⁶ in this embodiment. -12 F / m, The relative permittivity is 2.3 in this embodiment. In this embodiment, the insulating material A1 was polarized and depolarized under four polarization electric fields of 20 kV / mm, 40 kV / mm, and 70 kV / mm, respectively, and the depolarization charge decay curve of the insulating material A1 was obtained, as shown below. Figure 1 As shown, the carrier mobility under each polarization field fluctuates with increasing decay time, and the higher the polarization field, the lower the overall level of carrier mobility.

[0030] Furthermore, based on carrier mobility μ(t) By correcting for the influence of the electric field using the Poole–Frenkel law, the trap energy level distribution of the insulating material under different polarization electric fields was obtained. The median Trapping energy levels can characterize insulating materials. The distribution of trapping energy levels in insulating materials under different polarization electric fields. The calculation expression is:

[0031] In the formula, It is the Boltzmann constant, which is 1.38 × 10⁻⁶. -23 ; It is the thermodynamic temperature, which is 298 K; The average distance between local states is 5 × 10⁻⁶. -9 m; It is the escape frequency, which is 10. 12 ~10 14 Hz; It is the electron charge, which is 1.6 × 10⁻⁶. -19 C; This refers to the polarization electric field, measured in kV / mm. This embodiment focuses on insulating material A1, and the trap energy level distributions of the insulating material under different polarization electric fields (20~70 kV / mm) are shown below. Figure 2 As shown, the trap energy level distribution of the insulating material under different polarization electric fields. It is a range within a polarized electric field. E Trapping energy level distribution of insulating materials under different polarization electric fields the median of The trap energy level reflects the insulating material; the median value under a 20 kV / mm polarization electric field is... =0.8181eV, under a polarization electric field of 30 kV / mm, median =0.91946eV, median at a polarization electric field of 40 kV / mm =0.9868eV, median under a polarization electric field of 50 kV / mm =1.05385eV, median value under a polarization electric field of 60 kV / mm =1.11169 eV, median value under a polarization electric field of 70 kV / mm. =1.14607 eV, the trap energy level distribution of the insulating material under different polarization electric fields increases with the increase of polarization electric field strength. the median of The larger the value, the higher the range of trap energy levels under different polarization electric fields of the insulating material.

[0032] Trapping energy level distribution under different polarization electric fields of insulating materials In this embodiment, data ranging from 20 to 50 kV / mm ((20, 0.81821), (30, 0.91946), (40, 0.9868), (50, 1.05385)) are selected, and the polarization electric field E and the trap energy level are fitted using an exponential decay function. The relationship between them, and the fitting relationship, are as follows:

[0033] in, This represents the average trap energy level of the insulating material under a non-polarized electric field, which is dominated by shallow traps. The amplitude of the trap level vibration. The characteristic electric field determines the sensitivity of the filling process to the electric field.

[0034] Substituting the polarization electric fields 60 and 70 into the above fitting equation, E Substituting =60 kV / mm, we get... U (60) = 1.099 eV, which has an error of 1.14% > 1% compared to the experimental value of 1.1169 eV in the trap energy level distribution diagram of the above insulating material under different polarization electric fields. Therefore, data from 20 to 60 kV / mm are further fitted to obtain:

[0035] Will E Substituting =70 kV / mm, we get... U(60) = 1.1498 eV, and the error between the experimental value of 1.14607 eV and the actual value is 0.33% < 1%. Therefore, the data of 20~60 kV / mm is sufficient to fit the relationship curve between the A1 trap energy level and the polarization electric field of the insulating material.

[0036] In the preferred embodiment, to make the fitting results more accurate, data from six points ranging from 20 to 70 kV / mm were selected, such as... Figure 3 As shown. The polarization electric field of the insulating material A1 is obtained. E and trap energy level U ( E Relationship curve:

[0037] Based on the fitted function, the polarization electric field can be extrapolated to obtain the trap energy levels of the insulating material under high fields. When the polarization electric field... E As the energy level approaches infinity, the field-assisted deep trap filling reaches saturation, and the corresponding saturation trap energy level is the limiting value of the material. At this point, we have: U ∞ =1.33eV. Simultaneously, the DC breakdown field strength of insulating material A1 was measured to be 477.25 kV / mm. To establish the relationship between the limiting trap level and the DC breakdown field strength, experiments need to be conducted on multiple materials.

[0038] Example 2 Based on the trap level-based dielectric strength evaluation method for insulating materials provided in Example 1, this example selects 0.1 mm thick insulating materials A1, A2, and A3, and 0.2 mm thick insulating materials B1, B2, and B3 as research objects to illustrate the method of the present invention, specifically including the following steps: Step 1: Utilizing DCIC- Q (t) The testing system tested six insulating materials: 0.1 mm thick insulating materials A1, A2, and A3; and 0.2 mm thick insulating materials B1, B2, and B3. The insulating samples were sequentially placed in a three-electrode system for polarization, with a polarization time of 600 s and a sampling step of 2 s. After polarization, the voltage was removed, and the depolarization time was 900 s with a sampling step of 2 s. The polarization electric field was sequentially increased from 20 kV / mm to 70 kV / mm, and the depolarization charge decay curves for different insulating materials under each polarization electric field were obtained.

[0039] Step 2: The depolarization charge decay curve of an insulating material can be used to calculate carrier mobility, as shown in the following expression:

[0040] Step 3: By using Poole–Frenkel's law to correct for the influence of the electric field, the trap energy level distribution of the insulating material under different polarization electric fields was obtained. Trapping energy level distribution of insulating materials under different polarization electric fields The calculation expression is:

[0041] Step 4: Trapping energy level distribution of insulating materials under different polarization electric fields It is a range. In a polarized electric field... E Trapping energy level distribution of insulating materials under different polarization electric fields the median of The trap energy levels reflect the properties of insulating materials. In different polarized electric fields, Fitting using an exponential decay function:

[0042] Based on the fitting formula of the exponential decay function, the trap energy levels, fitting functions, limiting energy levels when the polarization electric field approaches ∞, and DC breakdown field strengths of insulating materials A1, A2, and A3 in this embodiment under different electric fields are shown in Table 1 below: Table 1

[0043] As shown in Table 1, the trap energy levels of the three insulating materials all increase monotonically with the increase of polarization electric field strength, and eventually tend to their respective limiting energy levels. At the same time, the limiting energy level is positively correlated with the DC breakdown field strength, that is, the higher the limiting energy level, the greater the DC breakdown field strength of the material. This verifies that the method of evaluating dielectric strength by trap energy level parameters in this invention is scientific and reliable.

[0044] polarization electric field E Limiting energy level approaching ∞ U ∞ DC breakdown field strength E bd Plot the relationship curve, such as Figure 4 As shown. The fitting yields the following relationship between the two:

[0045] Limiting energy levels of three 0.2 mm thick insulating materials U ∞ DC breakdown field strength E bd The relational expression is as follows:

[0046] As the limiting energy level increases, the DC breakdown field strength of the material increases, indicating that the technical method provided by this patent effectively evaluates the dielectric strength of insulating materials through trap energy levels. It should be noted that this patent selected six insulating materials for implementation, three of which were 0.1 mm thick and the other three were 0.2 mm thick, resulting in two limiting energy levels. U ∞ DC breakdown field strength E bd The relationship is as follows. As more embodiments are added, the relationship may change. This is not because there is a problem with the method provided in this patent, but because the increased data makes the fitting results more accurate.

[0047] Example 3 Based on the method for evaluating the dielectric strength of insulating materials based on trap energy levels provided in Example 1, this example proposes a system for evaluating the dielectric strength of insulating materials based on trap energy levels, including a mobility calculation module, a trap energy level distribution calculation module, and a relationship fitting module. The mobility calculation module is used to obtain the depolarization charge decay curve of the insulating material and calculate the carrier mobility. μ(t) ; The trap energy level distribution calculation module is used to calculate based on carrier mobility. μ(t) By correcting the influence of the electric field using the Poole-Frenkel law, the effect of the external electric field on the carrier transport properties is eliminated, and the trap energy level distribution of the insulating material under different polarization electric fields is derived. ; The relationship fitting module is based on the trap energy level distribution of the insulating material under different polarization electric fields. By using an exponential decay function for fitting analysis, the limiting trap energy level under the critical electric field is determined. Then, by fitting multiple sets of measured data of the limiting trap energy level and the corresponding DC breakdown field strength, a quantitative relationship curve between the two is established, enabling rapid assessment of dielectric strength.

[0048] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for evaluating dielectric strength of a trap-energylevel-based insulating material, characterized by, Comprising the following steps: Obtaining the decay curve of the depolarization charge quantity of the insulating material, calculating the carrier mobility μ(t) ; Carrier mobility based μ(t) The trap energy distribution of insulating materials under different polarization electric fields is obtained by modifying the influence of electric field by Poole-Frenkel law ; Trap energy level distribution of insulating material under different polarization electric field An exponential decay function fitting is performed to obtain the limit trap energy level under the critical electric field, and a relationship curve between the limit trap energy level under the critical electric field and the direct current breakdown field strength is established.

2. The method of claim 1, wherein the method further comprises: The insulation material depolarization charge quantity decay curve is obtained, specifically, a polarization electric field is applied to the insulation material E 0 is polarized, then depolarized, and the insulation material depolarization charge quantity decay curve is collected.

3. The method of claim 2, wherein the method further comprises: The insulating material is polarized, specifically: DCIC- Q (t) The test system outputs a voltage to the insulating material for polarization, the polarization voltage is set to 1-100 kV / mm, and the polarization time is 60-6000 s, DCIC- Q (t) The sampling step of the device is 1-5 s; wherein, the depolarization is specifically: the depolarization time is 100-10000 s, DCIC- Q (t) The sampling step of the device is 1-5 s.

4. The method of claim 1, wherein the method further comprises: Based on the insulation material depolarization charge quantity decay curve, the ratio of charge quantity and insulation material volume is obtained, and then the carrier mobility is calculated μ(t) , carrier mobility μ(t) The calculation formula is as follows: wherein is the charge density, i.e. the ratio of the charge quantity to the volume of the insulating material, is the vacuum permittivity, is the relative permittivity.

5. The method of claim 4, wherein the method further comprises: Carrier mobility based μ(t) The trap energy distribution of insulating materials under different polarization electric fields is obtained by modifying the influence of electric field through Poole-Frenkel law Wherein the number of digits Characterize the trap energy level of insulating materials.

6. The method of claim 5, wherein the method further comprises: Trap energy level distribution of the insulating material under different polarization electric fields The calculation formula is as follows: wherein, is the Boltzmann constant, is the thermodynamic temperature, is the mean distance of the localized states, is the escape frequency, is the electronic charge, is the polarization electric field.

7. The method of claim 6, wherein the method further comprises: Trapping energy level distribution under different polarization electric fields of insulating materials The polarization electric field is fitted by an exponential decay function. E With trap energy level The relationship is fitted as follows: wherein E0is the average trap energy level of the insulating material when the electric field is zero, E0is the average trap energy level of the insulating material when the electric field is zero, E0is the average trap energy level of the insulating material when the electric field is zero, 8. The method of claim 7, wherein the method further comprises: When the error between the fitting value and the experimental value is less than 1%, the fitting is ended.

9. The method of claim 7, wherein the method further comprises: Based on the relationship between the polarization electric field E and the trap energy level , by extrapolating the polarization electric field, the trap energy level of the insulating material under the critical electric field is obtained, under the critical electric field, the field-assisted deep trap filling reaches saturation, and the corresponding saturation trap energy level is the limit value of the material, that is, the limit trap energy level under the critical electric field, the formula of the limit trap energy level under the critical electric field is as follows: 。 10. A trap-energylevel-based insulation-material dielectric strength evaluation system based on the trap-energylevel-based insulation-material dielectric strength evaluation method according to any one of claims 1 to 9, characterized by Comprising a mobility calculation module, a trap energy level distribution calculation module, and a relationship fitting module; The migration rate calculation module is configured to acquire a decay curve of the depolarization charge quantity of the insulating material and calculate the carrier migration rate μ (t) ; The trap level distribution calculation module is configured to calculate the trap level distribution of the insulating material under different polarization electric fields based on the carrier mobility μ(t) , the influence of the electric field is corrected by the Poole-Frenkel law . The relationship fitting module is based on the trap energy level distribution of the insulating material under different polarization electric fields. The polarization electric field is fitted by an exponential decay function. E With trap energy level The relationship between the limiting trap level under the critical electric field was obtained, and the relationship curve between the limiting trap level under the critical electric field and the DC breakdown field strength was established.

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