A method and system for evaluating the resistance of a zinc oxide varistor

Abstract

The present application relates to the technical field of power equipment testing and material resistance evaluation, and particularly relates to a zinc oxide resistor piece resistance evaluation method and system. The zinc oxide resistor piece resistance evaluation method comprises obtaining an initial impact residual voltage of a zinc oxide resistor piece to be tested and an initial leakage current under a preset constant direct current voltage; obtaining an impact residual voltage of a current round and a leakage current under the preset constant direct current voltage after each round of impact current application; calculating a residual voltage offset rate of the current round based on the initial impact residual voltage and the impact residual voltage of the current round; calculating a leakage current growth rate of the current round based on the initial leakage current and the leakage current of the current round; and determining the resistance of the zinc oxide resistor piece according to the change trend of the residual voltage offset rate and the leakage current growth rate with the impact round. The present application can provide a breakthrough quantitative evaluation method for the selection and safe and stable operation of high-reliability lightning protection equipment of a power system.

Description

Technical Field

[0001] This invention relates to the field of power equipment testing and material durability assessment technology, specifically to a method and system for assessing the durability of zinc oxide resistor sheets. Background Technology

[0002] In actual power system operation scenarios, surge arresters are often subjected to complex and variable electromagnetic environments. Zinc oxide resistors are core components of surge arresters and other overvoltage protection devices. With their excellent nonlinear volt-ampere characteristics, they play a crucial role in limiting overvoltages and releasing surge energy in power systems. The electrical performance and internal grain boundary stability of zinc oxide resistors directly determine the operational safety of the overvoltage protection equipment and even the entire power system.

[0003] Besides occasional extreme lightning strikes, zinc oxide resistors are more commonly subjected to multiple lightning strikes or system overvoltage surges with amplitudes below their single physical damage threshold during long-term service. This necessitates that zinc oxide resistors possess excellent multi-impact withstand capabilities. Therefore, in power equipment selection, factory inspection, and pre-grid testing, accurately assessing the withstand performance and health status of zinc oxide resistors under multiple cumulative impacts is a crucial aspect of ensuring high grid reliability.

[0004] Traditional single high-current impulse tests only provide a binary criterion of whether a device "explodes" or "does not explode," and conventional DC tests are severely insensitive to early microscopic damage. When using this traditional testing method for inspection and selection, the inability to quantify and assess the irreversible cumulative damage caused by repeated impacts to the grain boundaries within the resistor element means that "qualified" devices that perform normally in a single impulse test often experience rapid deterioration or even physical failure (such as thermal breakdown) once installed in an actual power grid and subjected to continuous multiple impact stresses. This prevents power maintenance personnel in real-world scenarios from obtaining accurate warnings of performance degradation before resistor failure, ultimately posing a significant potential safety hazard to expensive power equipment and the reliability of power supply systems.

[0005] Therefore, in the existing endurance assessment scenarios, there is an urgent problem to be solved concerning the actual operation safety of the power grid: traditional testing methods cannot effectively capture the early hidden cumulative damage caused by zinc oxide resistors under multiple impacts, which can easily lead to the risk of sudden failure of products that are judged to be qualified in actual service. Summary of the Invention

[0006] To address the technical problems of low accuracy and poor reliability in traditional zinc oxide resistance chip tolerance assessment methods, this invention provides solutions in the following aspects.

[0007] In a first aspect, the present invention provides a method for evaluating the tolerance of zinc oxide resistor sheets, comprising the following steps: The initial impact residual voltage and the initial leakage current under a preset constant DC voltage of the zinc oxide resistor under test are obtained. In response to applying at least three rounds of impact current to the zinc oxide resistor, the impact residual voltage and the leakage current under the preset constant DC voltage are obtained after each round of impact current application. Based on the initial impact residual voltage and the impact residual voltage of the current round, the residual voltage offset rate of the current round is calculated. Based on the initial leakage current and the leakage current of the current round, the leakage current growth rate of the current round is calculated. The withstand capability of the zinc oxide resistor is determined according to the changing trends of the residual voltage offset rate and the leakage current growth rate with the number of impact rounds.

[0008] In one embodiment, the method for obtaining the preset constant DC voltage includes: obtaining the initial DC reference voltage of the zinc oxide resistor, and weighting the initial DC reference voltage with a preset coefficient to obtain the preset constant DC voltage.

[0009] In one embodiment, before taking a measurement after each round of impact current is applied, a set time interval is further included; the set time interval is 30s to 120s.

[0010] In one embodiment, the methods for measuring the initial impact residual pressure and the impact residual pressure of the current round both include: applying a standard non-destructive measurement current to the zinc oxide resistive element and obtaining the voltage across its terminals.

[0011] In one embodiment, the application of impact current in at least three rounds, with the amplitude remaining constant or increasing in a stepwise manner, is carried out sequentially.

[0012] In one embodiment, the determination of the tolerance of the zinc oxide resistor includes: determining that the zinc oxide resistor has entered a critical damage state when the changes in the residual voltage offset rate and the leakage current growth rate meet a preset critical damage criterion; and determining its tolerance level based on the total number of impact cycles it has withstood before entering the critical damage state.

[0013] In one embodiment, the critical damage criterion includes: the value of the residual voltage offset rate is greater than a first preset threshold, and the value of the leakage current growth rate is greater than a second preset threshold.

[0014] In one embodiment, the first preset threshold is 5%; the second preset threshold is 200%.

[0015] In one embodiment, the critical damage criterion includes: the curve of the residual pressure offset rate changing with the number of impact cycles shows an accelerating inflection point, and the curve of the leakage current growth rate changing with the number of impact cycles shows a non-linear correlation and divergence trend with the curve of the residual pressure offset rate changing.

[0016] In a second aspect, the present invention also provides a zinc oxide resistor sheet tolerance assessment system, comprising: a processor and a memory; the memory storing computer program instructions for assessing the tolerance of zinc oxide resistor sheets, wherein when the processor executes the computer program instructions, it implements the zinc oxide resistor sheet tolerance assessment method as described above.

[0017] The beneficial effects of this invention are as follows: According to the present invention, in the actual selection and operation and maintenance scenarios of overvoltage protection equipment in power systems, a stepped cumulative impact test sequence is designed, and a dual-feature parameter model is constructed using residual voltage offset rate and leakage current growth rate. This model can accurately quantify and evaluate the degree of irreversible early cumulative micro-damage generated by the internal grain boundaries of zinc oxide resistors after multiple impacts by utilizing the dynamic offset changes of the dual parameters under cumulative impacts. By scientifically combining the critical damage criteria of static threshold and dynamic divergence trend, the model achieves accurate quantification and classification of irreversible early micro-damage inside overvoltage protection equipment under multiple electrical stress impacts. This model can provide early warning before physical failure of components, providing a breakthrough quantitative evaluation method for the selection and safe and stable operation of high-reliability lightning protection equipment in power systems.

[0018] Furthermore, by introducing a dual-parameter correlation early warning mechanism that combines dynamic evolution trends with static thresholds, this invention can keenly capture the gradual process of equipment performance degradation. It can issue accurate early warnings 1 to 2 times before the zinc oxide resistor sheet is physically damaged, greatly reducing the probability of misjudgment and providing sufficient response window for fault prevention and condition-based maintenance of power lightning protection equipment. Attached Figure Description

[0019] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein: Figure 1 An exemplary flow diagram of a zinc oxide resistor sheet tolerance assessment method according to an embodiment of the present invention is shown; Figure 2 A schematic diagram illustrating the tolerance assessment process of the zinc oxide resistor sheet using the present invention is shown. Figure 3 A schematic diagram of the composition of a zinc oxide resistor sheet tolerance assessment system according to an embodiment of the present invention is shown. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Zinc oxide resistors, as core components of overvoltage protection devices such as surge arresters, directly determine the safety of power equipment. Traditional single high-current impulse tests can only provide a binary criterion of pass or fail, failing to assess the irreversible cumulative damage generated at the grain boundaries within the resistor after multiple impulses below the failure threshold. Furthermore, conventional DC leakage current and reference voltage tests are insufficiently sensitive to early cumulative damage caused by impulses. Therefore, this invention provides a zinc oxide resistor withstand capability assessment method based on the correlation analysis of impulse residual voltage characteristic shift and leakage current. Utilizing conventional impulse and DC testing equipment, by designing specific test sequences and correlating the dynamic shifts between residual voltage and leakage current, the method quantitatively assesses the multi-stress withstand capability and early damage of the zinc oxide resistor.

[0022] Before implementing the evaluation method of this invention, standard basic testing equipment needs to be configured. Specifically, the hardware testing environment includes a standard impulse current generator and a DC leakage current testing device. The standard impulse current generator is configured to output an impulse current with a standard waveform (e.g., waveform parameters of 8 / 20μs); the DC leakage current testing device is configured to provide a high-precision constant DC bias voltage and has microampere-level current detection capability to ensure accurate capture of weak leakage currents.

[0023] Figure 1 An exemplary flow diagram of a zinc oxide resistor sheet withstand capability assessment method according to an embodiment of the present invention is shown. The method mainly includes the following steps: like Figure 1 As shown, in step S101, the initial impact residual voltage of the zinc oxide resistor under test and the initial leakage current under a preset constant DC voltage are obtained. In some embodiments, the preset constant DC voltage can be obtained by: obtaining the initial DC reference voltage of the zinc oxide resistor and weighting the initial DC reference voltage with a preset coefficient to obtain the preset constant DC voltage.

[0024] In step S102, in response to applying at least three rounds of impact current sequentially to the zinc oxide resistive sheet, the residual impact voltage of the current round and the leakage current under the preset constant DC voltage are acquired after each round of impact current application. Before measurement after each round of impact current application, a set time interval is allowed. This set time interval is between 30s and 120s. This time interval setting effectively avoids thermal breakdown damage caused by excessively short impact intervals leading to rapid internal heat accumulation, while also preventing reversible recovery of the grain boundary state due to excessively long intervals. This ensures that the data obtained from the test can most accurately capture and accumulate the microscopic damage caused to the device by each electrical stress, significantly improving the reliability and accuracy of parameter evaluation in practical engineering applications.

[0025] Furthermore, at least three rounds of impact current are applied in sequence, with the amplitude remaining constant or increasing in a stepwise manner.

[0026] In step S103, the residual pressure offset rate of the current round is calculated based on the initial impact residual pressure and the impact residual pressure of the current round.

[0027] In step S104, the leakage current growth rate of the current cycle is calculated based on the initial leakage current and the leakage current of the current cycle.

[0028] The methods for measuring the initial impact residual pressure and the impact residual pressure of the current round both include: applying a standard non-destructive measurement current to the zinc oxide resistive element and obtaining the voltage across its terminals.

[0029] In step S105, the withstand capability of the zinc oxide resistor is determined based on the changing trends of the residual voltage offset rate and leakage current growth rate with the number of impact cycles. In some embodiments, the process of determining the withstand capability of the zinc oxide resistor may include determining that the zinc oxide resistor has entered a critical damage state when the changes in the residual voltage offset rate and leakage current growth rate meet a preset critical damage criterion. Its withstand level is determined based on the total number of impact cycles it has withstood before entering the critical damage state. The aforementioned critical damage criterion may include two methods: threshold judgment and trend judgment.

[0030] In an exemplary scenario, the critical damage criteria include: the residual voltage offset rate is greater than a first preset threshold, and the leakage current growth rate is greater than a second preset threshold. Preferably, the first preset threshold can be set to 5%, and the second preset threshold can be 200%.

[0031] In another exemplary scenario, the critical damage criterion includes: the curve of the residual pressure offset rate changing with the number of impact cycles shows an accelerating inflection point, and the curve of the leakage current growth rate changing with the number of impact cycles shows a non-linear correlation and divergence trend with the curve of the residual pressure offset rate changing.

[0032] The above provides a brief description of the solution of the present invention. The solution of the present invention will be further elaborated in conjunction with specific embodiments below. Figure 2 A schematic diagram of the zinc oxide resistor sheet tolerance assessment process in which the present invention is applied is shown.

[0033] like Figure 2 As shown, step S201: Preparation and initial measurement.

[0034] Obtain the zinc oxide resistor sample to be tested, and measure and record the initial DC reference voltage of the sample using a DC leakage current testing device. V 1mA (0). Next, the initial leakage current of the sample was measured at a preset constant voltage. I leak (0). Subsequently, a standard non-destructive measurement current was output from a standard impact current generator to perform the first impact on the sample, and the initial impact residual pressure was measured and recorded. U res (0).

[0035] As a specific implementation scenario, a 10kV system zinc oxide resistive element was selected as the sample to be tested. The average initial DC reference voltage of the sample was measured by the equipment. V 1mA (0) is 25.3kV. The constant voltage is set to 0.75 times the initial DC reference voltage, and the initial leakage current is measured. I leak (0) is 28 μA. The sample was subjected to its first impact using a measuring current with a waveform of 8 / 20 μs and an amplitude of 5 kA, and the initial impact residual pressure was measured. U res (0) is 60.1kV.

[0036] Step S202: Perform a stepped cumulative impact test sequence.

[0037] In an exemplary scenario, the above samples are sequentially subjected to... M Wheel impact current test, including wheel parameters. M ≥3. After each impact, a set time interval must be waited for, during which the parameters after this impact must be measured. Specific measurement operations include: using a standard non-destructive measurement current to measure the... i Impact residual pressure of the sample after wheel impact U res ( i Simultaneously, under the aforementioned preset constant DC voltage, the leakage current of the sample is measured. I leak ( i ).

[0038] In this embodiment, the M The amplitude of the impact current can remain constant or increase in a stepwise manner. As a preferred option, the aforementioned time interval is preferably set to 30-120 seconds. When the time interval is shorter than 30 seconds, the heat generated inside the resistor due to the absorption of impact energy cannot be effectively dissipated, and the rapid heat accumulation can easily induce non-electrical aging thermal breakdown damage. When the time interval is longer than 120 seconds, the overall test cycle is excessively prolonged, and the grain boundary state inside the resistor may undergo reversible recovery due to thermal relaxation, thus failing to accurately capture the true cumulative damage level.

[0039] Therefore, in this embodiment, the interval time is preferably controlled to 60 seconds, which ensures that the grain boundary temperature is within a reasonable fluctuation range and accurately locks and accumulates the microscopic damage caused by each electrical stress. For example, multiple rounds of impact are performed using an 8 / 20μs impact current with a constant amplitude of 8kA. After each round of impact, a 60-second wait is waited before the current impact value is immediately obtained. U res ( i )and I leak ( i The data is subjected to continuous impact until the sample suffers significant physical damage or a drastic change in electrical properties.

[0040] Step S203: Calculate the characteristic parameter sequence. This characteristic parameter sequence includes residual voltage offset rate, leakage current growth rate, etc.

[0041] To quantify the drift of the macroscopic residual voltage characteristics of zinc oxide resistive elements under multiple impact stresses, the following formula is constructed to calculate the residual voltage offset rate after each round of impact, using the initial impact residual voltage as a benchmark: Δ U res% ( i )=[( U res ( i )- U res (0)) / U res (0)]×100%; Where, Δ U res% ( i ) indicates the first i Residual pressure offset rate after wheel impact U res ( i ) indicates the first i Impact residual pressure measured after wheel impact, U res(0) represents the initial impact residual pressure. From the above formula, it can be seen that when continuous impacts gradually damage the grain boundary structure, causing the current-voltage characteristics to deteriorate, the independent variable... U res ( i Compared to a constant benchmark U res (0) will increase, thus making the molecule larger, and the final output dependent variable Δ U res% ( i The value will show a positive increasing trend, and the increase of this value directly reflects the gradual deterioration of the nonlinear protection characteristics of the resistor under impact scenarios.

[0042] Similarly, in order to accurately characterize the insulation performance degradation of the resistor under a specific DC bias, the following formula for calculating the leakage current growth rate is constructed based on the initial leakage current: Δ I leak% ( i )=[( I leak ( i )- I leak (0)) / I leak (0)]×100%; Where, Δ I leak% ( i ) indicates the first i The rate of increase of leakage current after wheel impact I leak ( i ) indicates the first i Leakage current measured after wheel impact, I leak (0) represents the initial leakage current. From the above formula, it can be seen that when the microscopic grain boundary barrier is irreversibly damaged and reduced due to accumulated impacts, the independent variable flowing through the sample under a constant bias voltage... I leak ( i The value of Δ will increase significantly, leading to a rapid expansion of the molecule, and ultimately resulting in the calculated strain Δ. I leak% ( i The sharp increase reflects the extremely high sensitivity of this indicator to monitoring the early microscopic damage state of the resistor.

[0043] Step S204: Withstandability Assessment and Judgment. Specifically, the withstandability of the zinc oxide resistor is determined based on the changing trends of the residual voltage offset rate and the leakage current growth rate with the number of impact cycles.

[0044] In an exemplary scenario, based on ΔU res% ( i ) and Δ I leak% ( i A dynamic evaluation model is established based on the changing trend of impact cycles. When Δ U res% ( i ) and Δ I leak% ( i When the change in stress meets the preset critical damage criterion, the sample is determined to have entered the critical damage state. The multi-stress tolerance level is determined based on the number of impact cycles the sample endured before entering the critical damage state.

[0045] Specifically, the critical damage criterion in this embodiment includes a first criterion based on a static threshold and a second criterion based on a dynamic trend. Criterion one is set as: Δ U res% ( i The value exceeds the first preset threshold. α , and Δ I leak% ( i The value exceeds the second preset threshold. β Criterion two is set as follows: in successive impact cycles, Δ U res% ( i The curve of change of ) shows an inflection point of accelerated rise, and Δ I leak% ( i The change curve of ) shows a non-linear divergent trend.

[0046] A dynamic correlation analysis is conducted based on the measured data from the aforementioned implementation scenarios. After the third impact, the measured... U res (3) is 60.8kV, and Δ is calculated. U res% (3) is 1.2%; measured I leak (3) is 35 μA, and Δ is calculated. I leak% (3) was 25%. After the sixth round of testing, the two indicators increased to 2.7% and 86%, respectively. It can be seen that in the first six rounds of testing, the growth of both was relatively slow and roughly linearly correlated.

[0047] However, after the first round of shocks, Δ I leak% The growth rate accelerated significantly and far exceeded Δ U res%The growth rate of Δ began to show non-linear divergence in the data curve. At this point, applying criterion two, it was determined that a correlation divergence inflection point occurred around the 7th round. Furthermore, by the 9th impact, Δ U res% (9) It reached 5.7%, exceeding the first preset threshold. α The preferred value is 5%; at the same time Δ I leak% (9) It surged to 329%, significantly exceeding the second preset threshold. β The preferred value is 200%. At this point, the data strictly satisfies criterion one. Based on the above criteria, it can be accurately determined that the sample entered a critical damage state between rounds 7 and 9. The sample ultimately experienced physical failure in round 10.

[0048] For classifying the multiple stress tolerance levels, this embodiment establishes a quantitative grading system based on the total number of impact cycles completed by the sample before reaching the critical damage criterion. For example, it defines L1 as samples that withstand 3-5 impact cycles to reach critical damage, L2 as samples that withstand 6-10 impact cycles, and L3 as samples that withstand more than 10 impact cycles. Since the sample in the aforementioned implementation scenario effectively withstood 9 impact cycles before failure, it is precisely assessed as having L2 tolerance capability.

[0049] To verify the beneficial effects of the embodiments of the present invention, a comparative example using a traditional testing method is introduced. Another sample from the same batch as the aforementioned sample was subjected to a standard single 8 / 20μs, 40kA high-current impact test. This comparative sample did not suffer physical damage under the single impact and its residual voltage was qualified, and it was judged to be a qualified product according to traditional standards.

[0050] However, when the qualified comparative sample was placed in the cumulative impact test sequence of the present invention, it triggered the critical damage criterion prematurely after only 5 rounds of constant 8kA impacts, and was rated as a lower L1 level of tolerance according to the grading standard of the present invention.

[0051] The comparison clearly shows that traditional qualified products may still have a huge potential risk of damage when encountering multiple impact stresses in actual power systems. However, the method provided by the embodiments of the present invention not only successfully captures the dynamic process of performance degradation, but also, with the help of scientific dual-parameter correlation criteria, can issue accurate warnings 1-2 rounds before physical damage occurs, providing a new quantitative basis for the selection of high-reliability overvoltage protection devices.

[0052] The solution described above, by designing specific test sequences and utilizing conventional equipment to correlate and analyze the dynamic shifts between residual voltage and leakage current, achieves quantitative assessment of early damage. This process requires only a standard impulse generator and DC testing equipment, thus having low equipment requirements. It transforms static single-point testing into dynamic process tracking, effectively revealing the patterns of cumulative damage. Through correlation divergence criteria, systemic degradation can be identified before physical failure occurs, achieving early warning and effectively improving the reliability of the power system.

[0053] This invention also provides a zinc oxide resistor sheet tolerance assessment system, such as... Figure 3 As shown, the system includes a processor and a memory. The memory stores computer program instructions for evaluating the withstand capability of zinc oxide resistors. When the processor executes the computer program instructions, it implements a zinc oxide resistor withstand capability evaluation method as described in one or more of the foregoing embodiments. This zinc oxide resistor withstand capability evaluation method has been described in detail above and will not be repeated here.

[0054] While embodiments of the invention have been described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and intent of the invention. It should be understood that various alternatives to the embodiments described herein may be employed in the practice of the invention. The appended claims are intended to define the scope of the invention and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A method for evaluating the withstand capability of zinc oxide resistor sheets, characterized in that, Includes the following steps: The initial impact residual voltage of the zinc oxide resistor under test and the initial leakage current under a preset constant DC voltage are obtained. In response to applying at least three rounds of impact current sequentially to the zinc oxide resistor, the residual impact voltage of the current round and the leakage current under the preset constant DC voltage are obtained after each round of impact current is applied. Based on the initial impact residual pressure and the impact residual pressure of the current round, the residual pressure offset rate of the current round is calculated; Based on the initial leakage current and the leakage current of the current round, the leakage current growth rate of the current round is calculated; The tolerance of the zinc oxide resistor is determined based on the changing trends of the residual pressure offset rate and the leakage current growth rate with the number of impact cycles.

2. The method for evaluating the tolerance of zinc oxide resistor sheets according to claim 1, characterized in that, The method for obtaining the preset constant DC voltage includes: Obtain the initial DC reference voltage of the zinc oxide resistor, and calculate the preset constant DC voltage by weighting the initial DC reference voltage with a preset coefficient.

3. The method for evaluating the tolerance of zinc oxide resistor sheets according to claim 1, characterized in that, Before taking measurements after each round of impact current is applied, a set time interval is also included; the set time interval is 30s to 120s.

4. The method for evaluating the tolerance of zinc oxide resistor sheets according to claim 1, characterized in that, The methods for measuring the initial impact residual pressure and the impact residual pressure of the current round both include: A standard nondestructive measurement current is applied to the zinc oxide resistor, and the voltage across its terminals is obtained.

5. The method for evaluating the tolerance of zinc oxide resistor sheets according to claim 1, characterized in that, The impact current is applied in no less than three rounds in sequence, with its amplitude remaining constant or increasing in a stepwise manner.

6. The method for evaluating the tolerance of zinc oxide resistor sheets according to claim 1, characterized in that, The determination of the resistance of the zinc oxide resistor includes: When the changes in the residual voltage offset rate and the leakage current growth rate meet the preset critical damage criteria, the zinc oxide resistor is determined to have entered a critical damage state; and its tolerance level is determined based on the total number of impact cycles it has withstood before entering the critical damage state.

7. The method for evaluating the tolerance of zinc oxide resistor sheets according to claim 6, characterized in that, The critical damage criteria include: the residual voltage offset rate is greater than a first preset threshold, and the leakage current growth rate is greater than a second preset threshold.

8. The method for evaluating the tolerance of zinc oxide resistor sheets according to claim 7, characterized in that, The first preset threshold is 5%; the second preset threshold is 200%.

9. The method for evaluating the tolerance of zinc oxide resistor sheets according to claim 6, characterized in that, The critical damage criteria include: the curve of the residual pressure offset rate changing with the number of impact cycles shows an accelerating inflection point, and the curve of the leakage current growth rate changing with the number of impact cycles shows a non-linear correlation and divergence trend with the curve of the residual pressure offset rate changing.

10. A zinc oxide resistor sheet withstand capability assessment system, characterized in that, include: Processor and memory; The memory stores computer program instructions for evaluating the tolerance of zinc oxide resistor sheets. When the processor executes the computer program instructions, it implements the zinc oxide resistor sheet tolerance evaluation method as described in any one of claims 1-9.

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