A test system and test method for uneven aging of zinc oxide varistors

Abstract

This invention discloses a testing system and method for testing the aging non-uniformity of zinc oxide varistors. The system includes multiple measuring resistors, a DC aging voltage source, a multi-channel switching module, a voltage acquisition module, and a data processing module. The first electrode of the zinc oxide varistor under test is divided into multiple regions, with the second electrode serving as a common terminal. Each measuring resistor is connected in series between its respective region and the common ground terminal to form multiple measuring branches. Each measuring channel of the multi-channel switching module is connected in series between the first terminal of each measuring resistor and the input terminal of the voltage acquisition module. The output terminal of the voltage acquisition module is connected to the common ground terminal, so that the selected measuring channel and the voltage acquisition module are connected in series and then connected in parallel across the corresponding measuring resistor. This invention can detect the aging non-uniformity of zinc oxide varistors, accurately distinguish the aging degree of different regions, and provide data support for optimizing the sintering process and improving overall uniformity.

Description

Technical Field

[0001] This invention relates to the field of zinc oxide varistor sintering process optimization, and in particular to a testing system and method for testing the aging non-uniformity of zinc oxide varistors. Background Technology

[0002] Metal oxide surge arresters, with zinc oxide varistors as their core material, are important power equipment that protects the insulation of power cables from lightning strikes, operational overvoltages, and other damage, and maintains the safe and stable operation of power cables.

[0003] Damage to ZnO surge arresters occurs frequently during operation, and operational data shows that surge arrester failures account for a significant proportion of power distribution faults. Therefore, the safe and reliable operation of surge arresters is a crucial factor determining the safe and stable operation of a power system. Because ZnO surge arresters are subjected to induced voltage for extended periods, the zinc oxide varistors may age, posing a potential threat to the insulation of high-voltage cables.

[0004] Numerous cases of ZnO surge arrester failures have revealed that the aging failure of zinc oxide varistors often occurs in a specific localized area of ​​the zinc oxide varistor, proving that zinc oxide varistors do not age uniformly.

[0005] In existing technologies, only the overall leakage current of zinc oxide varistors is monitored, which cannot reveal the aging differences in different regions and makes it difficult to locate the region with the highest degree of aging. Therefore, it cannot provide targeted improvement directions for sintering process optimization. Summary of the Invention

[0006] This invention provides a testing system and method for testing the aging non-uniformity of zinc oxide varistors, which can identify the easily broken-down areas of zinc oxide varistors, provide improvement directions for enhancing the overall uniformity and aging resistance of zinc oxide varistors, and promote the optimization of the sintering process of zinc oxide varistors.

[0007] The technical solution of this application is as follows: In a first aspect, this application provides a testing system for the aging non-uniformity of zinc oxide varistors. The testing system includes multiple measuring resistors, a DC aging voltage source, a multi-channel switching module, a voltage acquisition module, and a data processing module.

[0008] The first electrode of the zinc oxide varistor under test is divided into multiple regions, while the second electrode of the zinc oxide varistor is a complete electrode, serving as the common terminal.

[0009] Each measuring resistor is connected in series between each area and the common ground terminal. The first end of each measuring resistor is electrically connected to the corresponding area, and the second end of each measuring resistor is connected to the common ground terminal to form multiple parallel measuring branches.

[0010] The positive terminal of the DC aging voltage source is connected to the second electrode of the zinc oxide varistor, and the negative terminal of the DC aging voltage source is connected to the common ground terminal, which is used to apply aging voltage to the zinc oxide varistor and each measurement branch.

[0011] The multi-channel switching module includes multiple measurement channels, each of which is connected in series between the first end of each measuring resistor and the input end of the voltage acquisition module, and is used to sequentially close the internal switch of the corresponding channel at set time intervals.

[0012] The output of the voltage acquisition module is connected to the common ground terminal, so that the selected measurement channel and the voltage acquisition module are connected in series and then connected in parallel across the two ends of the measurement resistor of the corresponding branch, which is used to acquire the voltage division data of the measurement resistor corresponding to the selected measurement channel.

[0013] The data processing module is connected to the voltage acquisition module and is used to calculate the leakage current and / or voltage difference of each region based on the voltage division data of each measuring resistor, and to evaluate the aging status of each region of the zinc oxide varistor based on the calculation results, and to determine the region with a high degree of aging.

[0014] Specifically, the testing system for the aging non-uniformity of zinc oxide varistors provided in the first aspect divides one electrode of the zinc oxide varistor into multiple regions and measures the resistance in series in each region. This enables parallel monitoring of the aging behavior of the varistor at different spatial locations, overcoming the limitation of traditional methods that can only detect the overall leakage current and cannot distinguish regional differences. This provides data support for optimizing the sintering process of zinc oxide varistors and improving overall uniformity. By using a multi-channel switching module to sequentially close the internal switches of corresponding channels at set time intervals, only a small number of voltage acquisition modules are needed to complete the acquisition of multiple signals, significantly reducing the system hardware cost and complexity.

[0015] Each measurement channel of the multi-channel switching module is connected in series between the first end of the measuring resistor and the input end of the voltage acquisition module. The output end of the voltage acquisition module is connected to the common ground. This ensures that the selected measurement channel and the voltage acquisition module are connected in series and then connected in parallel across the two ends of the measuring resistor. This connection method ensures that the multi-channel switching module is not inserted into the main power circuit and does not change the impedance of the main circuit, thus guaranteeing the accuracy of leakage current measurement.

[0016] The data processing module can calculate leakage current and / or voltage differences based on voltage divider data, providing a hardware foundation for two different aging evaluation methods. Users can flexibly choose the evaluation method according to actual testing needs. Furthermore, the two evaluation methods can complement each other, improving the accuracy of detection.

[0017] In one possible design, the multiple regions are several equal-area regions that are uniformly divided from the first side electrode, and the division is done by cutting only the electrode surface.

[0018] Specifically, the testing system for the aging non-uniformity of zinc oxide varistors provided by this embodiment divides the electrodes into equal-area regions, ensuring electrical comparability between regions. This allows the differences in leakage current or voltage between different regions to accurately reflect the spatial distribution of aging, rather than being caused by differences in area. "Cutting only the electrode surface" means that the zinc oxide varistor body is not damaged; only the surface electrodes are scraped off to achieve regional electrical isolation. This division method does not change the microstructure and electrical characteristics of the resistor body, ensuring the integrity of the resistor body during the aging test, and enabling the measurement results to accurately reflect the aging behavior of the resistor body. Furthermore, the combination of equal-area partitioning and surface-only cutting allows for easy tracing of the exact location of the region with the highest aging degree on the resistor after the test, providing clear direction for process optimization.

[0019] In one possible design, multiple measuring resistors have the same resistance value. In this way, the voltage across each measuring resistor directly reflects the magnitude of the leakage current in the corresponding area, and the voltage difference represents the leakage current difference. There is no need to perform resistance normalization correction, which simplifies the data processing flow.

[0020] In one possible design, the resistance value of each measuring resistor is configured such that its voltage division is less than 0.01 times the aging voltage and less than the withstand voltage of the multi-channel switching module and the voltage acquisition module.

[0021] Specifically, the voltage division of the measuring resistor is less than 0.01 times the aging voltage, meaning the resistance of the measuring resistor is much smaller than the equivalent impedance of each region of the zinc oxide varistor under the aging voltage. This configuration ensures that the impact of the series connection of the measuring resistor on the main power circuit is negligible, and the aging voltage borne by each region is essentially equal to the applied aging voltage, without affecting the authenticity and reliability of the aging process. The voltage division of the measuring resistor is less than the withstand voltage of the multi-channel switching module and the voltage acquisition module, ensuring that the measurement signal is within the safe input range of the equipment, avoiding damage to the acquisition equipment due to signal overvoltage, and guaranteeing the long-term operational stability of the system.

[0022] In one possible design, the data processing module includes a region grouping program unit, which groups the set of test data from multiple branches collected by the voltage acquisition module according to time intervals, reassigns the test data to each region, and supplements the aging time information corresponding to each region.

[0023] Specifically, the mixed dataset is regrouped according to time intervals using a regional grouping program unit, systematically mapping scattered data to each region and establishing a clear one-to-one correspondence between data and spatial location. Aging time information for each region is supplemented, giving each data point a clear time coordinate, providing a data structure foundation for plotting leakage current-time evolution curves. The grouped data can be directly used for horizontal comparisons between different regions, significantly improving the efficiency and accuracy of data processing.

[0024] In one possible design, the multi-channel switching module is a multi-channel PLC module.

[0025] Specifically, the PLC module is highly programmable, allowing users to flexibly set the channel switching sequence, switching time interval, and number of cycles according to testing needs, adapting to the requirements of different aging test schemes. Furthermore, the PLC module possesses industrial-grade reliability and anti-interference capabilities, enabling long-term stable operation in high-temperature (120℃) aging environments, ensuring the continuity and reliability of data acquisition during extended aging tests.

[0026] Secondly, based on the same inventive concept, this application also provides a method for testing the aging non-uniformity of zinc oxide varistors using any of the above-mentioned testing systems, the method comprising the following steps: S1) Apply aging voltage to each branch.

[0027] S2) Using a multi-channel switching module, the internal switches of the corresponding channels are closed sequentially at set time intervals, and the voltage division data of the measurement resistors corresponding to the selected measurement channels are collected through the voltage acquisition module.

[0028] S3) Calculate the leakage current of each region based on the voltage division data of each measuring resistor, and draw the evolution graph of the leakage current of each region with aging time based on the leakage current of each region at different times. Determine the time required for each region to enter a stable state based on the evolution graph. The shorter the time required, the higher the degree of aging and the easier it is to break down.

[0029] Specifically, based on the method for testing the aging non-uniformity of zinc oxide varistors provided in the second aspect, the aging process of each region is visualized by plotting the evolution of leakage current over aging time. This allows for an intuitive observation of the changing trends and evolution characteristics of leakage current in different regions. Using the "time required to reach a steady state" as an evaluation index of the aging degree, regions with higher aging degrees reach a steady state more quickly (i.e., the aging response is more rapid). This criterion has clear physical meaning and is easy to quantify and compare. Furthermore, this method is based on the leakage current-time evolution graph, eliminating the need for complex equivalent circuit models or parameter fitting. It is simple to operate and suitable for rapid on-site evaluation in engineering projects.

[0030] In one possible design, step S3) further includes: starting the aging time with the i-th region. Corresponding leakage current Using this as an initial value, calculate the relative change in leakage current for the i-th region at the k-th sampling time: .in, For the i-th region in Leakage current at any given moment.

[0031] Calculate the rate of change of leakage current between two adjacent sampling times: .

[0032] When judging the degree of aging, when the time required to enter a stable state is close, the relative amount of change and the rate of change are compared in turn.

[0033] Specifically, the relative change in leakage current is normalized based on the initial leakage current of each region, eliminating the interference of differences in initial leakage current between different regions on the assessment of aging degree, thus making the aging degree between regions comparable. The rate of change of leakage current reflects the response speed of each region to aging stress; the greater the rate of change, the more drastic the change in aging degree of that region per unit time, and the higher its aging sensitivity. This method first uses the time required to reach a steady state as the main criterion, and then compares the relative change and the rate of change sequentially when these indicators are close, achieving a refined assessment of the aging degree and avoiding misjudgments that may be caused by a single indicator.

[0034] Thirdly, based on the same inventive concept, this application also provides a second method for testing the aging non-uniformity of zinc oxide varistors using any of the above-mentioned testing systems, the method comprising the following steps: J1) Apply aging voltage to each branch.

[0035] J2) Using a multi-channel switching module, the internal switches of the corresponding channels are closed sequentially at set time intervals, and the voltage division data of the measured resistors in the selected branch are collected through the voltage acquisition module.

[0036] J3) Calculate the voltage difference of each region based on the voltage division data of each measuring resistor, and evaluate the aging status of each region of the zinc oxide varistor based on the calculation results to determine the region with a high degree of aging.

[0037] Specifically, this method does not rely on the absolute value of leakage current in each region as the primary criterion. Instead, it uses the relative voltage difference between different regions at the same time to evaluate spatial non-uniformity. This self-referenced comparison method is insensitive to overall fluctuations in aging voltage, thus improving the reliability of the evaluation results. Furthermore, compared with evaluation methods based on the absolute value of leakage current, this method can reduce the impact of overall fluctuations in aging voltage and changes in overall sample current on the evaluation results.

[0038] In one possible design, the steps for assessing the aging status of different regions of the zinc oxide varistor based on voltage differences specifically include: At the k-th sampling time, calculate the average value of the sampled voltage in each region: Where N is the total number of regions. This represents the voltage value of the i-th region at the k-th sampling time.

[0039] Calculate the local aging deviation coefficient of the i-th region: . This represents the voltage value of the i-th region at the moment aging begins. This represents the average value of the sampled voltage in each region at the moment aging begins.

[0040] Local aging deviation coefficient A i (t k ) The larger the value, the more significant the voltage deviation of the i-th region relative to its initial state. A i (t k ) The largest area is identified as the area with the highest degree of aging and change. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the zinc oxide varistor electrode region segmentation provided in an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the composition structure of a test system for the aging non-uniformity of a zinc oxide varistor provided in an embodiment of the present invention.

[0043] Figure 3 The graph shows the evolution of leakage current in different regions of the zinc oxide varistor as a function of aging time, as provided in the embodiments of the present invention.

[0044] The attached diagram is labeled as follows: 1. Zinc oxide varistor. 11. First side electrode. 12. Second side electrode. 111. Region. 2. Measuring resistor. 3. DC aging voltage source. 4. Multi-channel PLC module. 5. Voltmeter. 6. Data processing module. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and drawings of this application are intended to cover non-exclusive inclusion.

[0047] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] The present application will be described in detail below with reference to the accompanying drawings.

[0049] Figure 1 This is a schematic diagram of the electrode region division for a zinc oxide varistor provided in an embodiment of the present invention. The zinc oxide varistor 1 is coated with aluminum electrodes on both sides. Before conducting an aging non-uniformity test, the electrode on the first side needs to be divided into multiple regions 111. The areas of the multiple regions 111 can be equal or unequal. Generally, the multiple regions 111 are regions of equal area. Figure 1As shown, in one embodiment of this application, the first side electrode 11 can be divided into 16 square regions 111 of 10×10mm each, and 8 of these regions 111 are selected for series measurement of the resistor 2. The second side electrode 12 of the zinc oxide varistor 1 is a complete electrode and serves as the common terminal. In this way, by physically dividing the first side electrode 11, a large electrode is disassembled into multiple independent small electrodes, and each region 111 becomes an independent electrical measurement unit.

[0050] Figure 2 This is a schematic diagram illustrating the structural composition of a testing system for the aging non-uniformity of a zinc oxide varistor, provided in an embodiment of the present invention. Please refer to... Figure 2 In one embodiment of this application, the testing system for the uneven aging of zinc oxide varistors includes multiple measuring resistors 2, a DC aging voltage source 3, a multi-channel PLC module 4, a voltmeter 5, and a data processing module 6. The first electrode 11 of the zinc oxide varistor 1 under test is divided into multiple regions 111, and the second electrode 12 of the zinc oxide varistor 1 is a complete electrode, serving as a common terminal. Each measuring resistor 2 is connected in series between each region 111 and the common ground terminal. The first terminal of each measuring resistor 2 is electrically connected to the corresponding region 111, and the second terminal of each measuring resistor 2 is connected to the common ground terminal, forming multiple parallel measuring branches. The positive terminal of the DC aging voltage source 3 is connected to the second electrode 12 of the zinc oxide varistor 1, and the negative terminal of the DC aging voltage source 3 is connected to the common ground terminal, used to apply aging voltage to the zinc oxide varistor 1 and each measuring branch. The multi-channel PLC module 4 includes multiple measuring channels, each measuring channel being connected in series between the first terminal of each measuring resistor 2 and the input terminal of the voltage acquisition module, used to sequentially close the internal switch of the corresponding channel at set time intervals.

[0051] The output terminal of the voltage acquisition module is connected to the common ground terminal, so that the selected measurement channel and the voltage acquisition module are connected in series and then connected in parallel across the two ends of the corresponding branch measurement resistor 2, which is used to acquire the voltage division data of the measurement resistor 2 corresponding to the selected measurement channel.

[0052] The data processing module 6 is connected to the voltage acquisition module and is used to calculate the leakage current and / or voltage difference of each region 111 based on the voltage division data of each measuring resistor 2, and to evaluate the aging status of each region 111 of the zinc oxide varistor 1 based on the calculation results, and to determine the region 111 with a high degree of aging.

[0053] In the testing system, multiple measuring resistors 2 have the same resistance value, for example, all are high-precision 10kΩ resistors. The resistance value of each measuring resistor 2 is configured such that its voltage division is less than 0.01 times the aging voltage, and less than the withstand voltage of the multi-channel switching module and the voltage acquisition module. The aging voltage is 0.8 times the rated voltage Ub of the zinc oxide varistor 1, and the DC aging temperature is 120℃.

[0054] It should be noted that, Figure 2 This is merely one specific embodiment of this application. A multi-channel acquisition module refers to a data acquisition device that has multiple analog input channels and can switch between channels via electronic switches. In addition to using a multi-channel PLC module 4, data acquisition cards, distributed I / O modules, etc., can also be used.

[0055] Data processing module 6 refers to a physical unit containing a processor (CPU / MCU), memory, and I / O interfaces. Specifically, it can take the form of an industrial control computer, an embedded motherboard, or a cloud virtual server. Data processing module 6 can be integrated into the multi-channel PLC module 4 or function as independent host computer software.

[0056] The method for testing the aging non-uniformity of zinc oxide varistors based on the above-mentioned testing system includes the following steps: S1: Apply aging voltage to each branch. The positive terminal of the DC aging voltage source 3 is connected to the second electrode 12 of the zinc oxide varistor 1, and the negative terminal is connected to the common ground terminal. Apply a DC aging voltage with an amplitude of 0.8 times the rated voltage of the zinc oxide varistor 1. The DC aging temperature is 120℃.

[0057] S2: Use a 12-channel PLC module to connect the measuring resistor 2 and the voltmeter 5, and switch the measurement every 5 minutes to measure the voltage of the measuring resistor 2 connected in series in different areas 111.

[0058] S3: Calculate the leakage current of each region 111 based on the voltage divider data of each measuring resistor 2. Since the resistance value of each measuring resistor 2 is known (10kΩ), the current flowing through each measuring resistor 2, i.e., the leakage current of each region, can be calculated according to Ohm's law I=U / R.

[0059] Based on the leakage current at different times in each region, plot the evolution of the leakage current of 111 in each region with aging time (e.g., Figure 3 (As shown). Figure 3 The eight curves in the figure correspond to the evolution of leakage current in eight regions over aging time.

[0060] Based on the evolution diagram, the time required for each region to enter a stable state is determined. Curve 6 enters the stable stage earliest as the aging time increases, indicating that region 111, numbered 6, has the fastest aging response and the highest aging sensitivity. Therefore, region 111, numbered 6, is determined to be the region with the highest degree of aging, that is, region 111, numbered 6, has the worst anti-aging performance and is the most easily broken down.

[0061] It should be noted that in some other embodiments of this application, step S3) further includes starting the aging time at the i-th region. Corresponding leakage current Using this as an initial value, calculate the relative change in leakage current for the i-th region at the k-th sampling time: .in, For the i-th region in Leakage current at any given moment.

[0062] Calculate the rate of change of leakage current between two adjacent sampling times: .

[0063] When judging the degree of aging, when the time required to enter a stable state is close, the relative amount of change and the rate of change are compared in turn.

[0064] Another method for testing the aging non-uniformity of zinc oxide varistors based on the above test system includes the following steps: J1: Apply aging voltage to each branch. The positive terminal of the DC aging voltage source 3 is connected to the second electrode 12 of the zinc oxide varistor 1, and the negative terminal is connected to the common ground terminal. Apply a DC aging voltage with an amplitude of 0.8 times the rated voltage of the zinc oxide varistor 1. The DC aging temperature is 120℃.

[0065] J2: Using a multi-channel switching module, the internal switches of the corresponding channels are closed sequentially at set time intervals, and the voltage division data of the measurement resistor 2 corresponding to the selected measurement channel is collected through the voltage acquisition module.

[0066] J3: Calculate the voltage difference of each region 111 based on the voltage divider data of each measuring resistor 2, and evaluate the aging status of each region 111 of the zinc oxide varistor 1 based on the calculation results, and determine the region 111 with a high degree of aging.

[0067] Specifically, while maintaining a continuous DC aging voltage, the multi-channel switching module sequentially selects the corresponding measurement channels for each region at set time intervals to measure the voltage across the series-connected measurement resistor 2 in each region. Since the resistance value of the series-connected measurement resistor 2 is the same in each region, the voltage difference across each measurement resistor 2 can characterize the difference in leakage current between different regions.

[0068] At the k-th sampling time, calculate the average value of the sampled voltage in each region: Where N is the total number of regions.

[0069] Furthermore, calculate the local aging deviation coefficient for the i-th region: .

[0070] Local aging deviation coefficient A i (t k ) The larger the value, the more significant the voltage deviation of the i-th region relative to its initial state. A i (t k ) The largest area is identified as the area with the highest degree of aging and change.

[0071] The second aging evaluation method does not use the absolute value of leakage current in each region as the criterion, but instead uses the relative voltage difference between different regions at the same time to evaluate spatial non-uniformity. This method facilitates rapid multi-channel measurements, is more sensitive to minute differences between different regions, and can reduce the impact of overall aging voltage fluctuations and overall sample current changes on the evaluation results. It is suitable for identifying localized aging non-uniformity.

[0072] In summary, the two methods described above evaluate the aging state of zinc oxide varistors from different perspectives. The first aging evaluation method is suitable for long-term aging process monitoring, evaluating the aging response speed, degree of change, and time required to reach a stable state by analyzing the temporal evolution of leakage current in each region. The second aging evaluation method is suitable for multi-channel rapid detection and screening of local non-uniformity, identifying the region with the most significant deviation from the overall state by comparing the relative voltage difference between different regions at the same time. The first method focuses on temporal evolution, while the second method focuses on spatial differences. The evaluation results of the two methods can be mutually verified, thus providing a more comprehensive evaluation of the aging non-uniformity of zinc oxide varistors.

Claims

1. A testing system for the aging non-uniformity of zinc oxide varistors, characterized in that, It includes multiple measuring resistors, a DC aging voltage source, a multi-channel switching module, a voltage acquisition module, and a data processing module; The first electrode of the zinc oxide varistor under test is divided into multiple regions, and the second electrode of the zinc oxide varistor is a complete electrode, serving as a common terminal. Each of the measuring resistors is connected in series between each of the regions and the common ground terminal. The first end of each measuring resistor is electrically connected to the corresponding region, and the second end of each measuring resistor is connected to the common ground terminal to form multiple parallel measuring branches. The positive terminal of the DC aging voltage source is connected to the second electrode of the zinc oxide varistor, and the negative terminal of the DC aging voltage source is connected to the common ground terminal, which is used to apply aging voltage to the zinc oxide varistor and each measurement branch. The multi-channel switching module includes multiple measurement channels, each of which is connected in series between the first end of each measurement resistor and the input end of the voltage acquisition module, and is used to sequentially close the internal switch of the corresponding channel at a set time interval. The output terminal of the voltage acquisition module is connected to the common ground terminal, so that the selected measurement channel is connected in series with the voltage acquisition module and then connected in parallel across the two ends of the measurement resistor of the corresponding branch, for acquiring the voltage division data of the measurement resistor corresponding to the selected measurement channel; The data processing module is connected to the voltage acquisition module and is used to calculate the leakage current and / or voltage difference of each region based on the voltage division data of each of the measuring resistors, and to evaluate the aging status of each region of the zinc oxide varistor based on the calculation results, and to determine the region with a high degree of aging.

2. The testing system for the aging non-uniformity of zinc oxide varistors according to claim 1, characterized in that, The plurality of regions are several equal-area regions that are uniformly divided from the first side electrode, and the division is performed by cutting only the electrode surface.

3. The testing system for the aging non-uniformity of zinc oxide varistors according to claim 1, characterized in that, The resistance values ​​of the multiple measured resistors are the same.

4. The testing system for the aging non-uniformity of zinc oxide varistors according to claim 3, characterized in that, The resistance value of each of the measuring resistors is configured such that its voltage division is less than 0.01 times the aging voltage, and less than the withstand voltage of the multi-channel switching module and the voltage acquisition module.

5. The testing system for the aging non-uniformity of zinc oxide varistors according to claim 1, characterized in that, The data processing module includes a region grouping program unit, which is used to group the set of test data from multiple branches collected by the voltage acquisition module according to time intervals, re-map the test data to each region, and supplement the aging time information corresponding to each region.

6. The test system for the aging non-uniformity of zinc oxide varistors according to any one of claims 1 to 5, characterized in that, The multi-channel switching module is a multi-channel PLC module.

7. A method for testing the aging non-uniformity of zinc oxide varistors based on the testing system according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1) Apply aging voltage to each branch; S2) Using a multi-channel switching module, the internal switches of the corresponding channels are closed sequentially at set time intervals, and the voltage division data of the measurement resistors corresponding to the selected measurement channels are collected through the voltage acquisition module. S3) Calculate the leakage current of each region based on the voltage divider data of each of the measured resistors, and plot the evolution of the leakage current of each region with aging time based on the leakage current of each region at different times. Determine the time required for each region to enter a stable state based on the evolution graph. The shorter the time required, the higher the degree of aging and the easier it is to break down.

8. A method for testing the aging non-uniformity of zinc oxide varistors based on the testing system described in claim 7, characterized in that, Step S3) also includes: starting the aging time with the i-th region. Corresponding leakage current Using these as initial values, calculate the relative change in leakage current for the i-th region at the k-th sampling time. : ;in, For the i-th region in Leakage current at any given moment; Calculate the rate of change of leakage current between two adjacent sampling times: ； When judging the degree of aging, when the time required to enter a stable state is close, the relative amount of change and the rate of change are compared in turn.

9. A method for testing the aging non-uniformity of zinc oxide varistors based on the testing system according to any one of claims 1 to 6, characterized in that, Includes the following steps: J1) Apply aging voltage to each branch; J2) Using a multi-channel switching module, the internal switches of the corresponding channels are closed sequentially at set time intervals, and the voltage division data of the measured resistor in the selected branch is collected by the voltage acquisition module. J3) Calculate the voltage difference of each region based on the voltage divider data of each of the measured resistors, and evaluate the aging status of each region of the zinc oxide varistor based on the calculation results, and determine the region with a high degree of aging.

10. A method for testing the aging non-uniformity of zinc oxide varistors based on the testing system of claim 9, characterized in that, The steps for assessing the aging status of different regions of a zinc oxide varistor based on voltage differences specifically include: At the k-th sampling time, calculate the average value of the sampled voltage in each region. : Where N is the total number of regions; This represents the voltage value of the i-th region at the k-th sampling time; Calculate the local aging deviation coefficient of the i-th region: ; This represents the voltage value of the i-th region at the moment aging begins; This represents the average value of the sampled voltage in each region at the moment aging begins; Local aging deviation coefficient A i (t k ) The larger the value, the more significant the voltage deviation of the i-th region relative to its initial state. A i (t k ) The largest area is identified as the area with the highest degree of aging and change.

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