A method, system, device and storage medium for testing a surge arrester

Abstract

The present disclosure relates to the technical field of lightning protection detection, and particularly relates to a lightning arrester through-flow test method, system, device and storage medium, wherein the method comprises the following steps: acquiring multiple lightning stroke parameters, constructing a combined test sequence based on the multiple lightning stroke parameters, and determining a lightning current peak value and a lightning time interval based on the combined test sequence; determining lightning test parameters based on the lightning current peak value and the lightning time interval, and constructing a test unit based on the lightning test parameters; testing the lightning arrester based on the test unit, collecting lightning arrester test parameters, and determining a test time interval based on the lightning arrester test parameters; testing the lightning arrester based on the test unit and the test time interval, acquiring voltage variation and leakage current growth multiple before and after lightning stroke of the lightning arrester, and determining a through-flow grade of the lightning arrester based on the voltage variation and the leakage current growth multiple before and after lightning stroke of the lightning arrester and a preset threshold, to obtain a determination result, thereby realizing hidden detection of the lightning arrester and improving test effectiveness.

Description

Technical Field

[0001] This disclosure relates to the field of lightning protection testing technology, and in particular to a method, system, device and storage medium for testing the current carrying capacity of a surge arrester. Background Technology

[0002] Groundless transmission lines are widely used in mountainous and rural areas with complex terrain due to their low cost and convenient construction. However, due to the lack of shielding and current diversion provided by an overhead ground wire, the lightning tripping rate of groundless lines is 3-5 times higher than that of grounded lines, and they are more susceptible to multiple lightning strikes. According to field fault statistics, about 40% of surge arrester failures in groundless lines are caused by multiple lightning strikes—the first lightning strike causes the surge arrester to absorb some energy, and subsequent lightning strikes (with high current rise rate and short wavefront time) can cause the surge arrester varistors to break down due to energy accumulation or thermal runaway failure.

[0003] Because existing tests only use breakdown as the failure criterion, surge arresters that pass the test may still fail shortly after being put into operation, indicating that the test is not effective enough. Summary of the Invention

[0004] To address the aforementioned technical issues, this disclosure provides a surge arrester current-carrying test method, system, device, and storage medium.

[0005] This disclosure provides a method for testing the current carrying capacity of a surge arrester, including: Obtain multiple lightning strike parameters, construct a combined test sequence of the first lightning strike and multiple subsequent lightning strikes based on the multiple lightning strike parameters, and determine the peak lightning current and lightning strike time interval based on the combined test sequence; The lightning strike test parameters are determined based on the peak lightning current and the lightning strike time interval, and a test unit is constructed based on the lightning strike test parameters; The surge arrester is tested using the test unit, the surge arrester test parameters are collected, and the test time interval is determined based on the surge arrester test parameters. The surge arrester is tested based on the test unit and the test time interval to obtain the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike. Based on the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike and a preset threshold, the current carrying capacity of the surge arrester is determined, and the determination result is obtained.

[0006] Further, the step of determining lightning strike test parameters based on the peak lightning current and the lightning strike time interval, and constructing a test unit based on the lightning strike test parameters, includes: The rated output current of the impulse current generator is determined by the peak value of the lightning strike current. The damping resistance is determined by the peak value of the lightning strike current and the residual voltage of the surge arrester; The grounding resistance limit is determined by the peak value of the lightning current and the voltage to ground of the surge arrester. The test unit is constructed based on the rated output current of the impulse current generator, the damping resistor, and the grounding resistance limit. The test unit includes: the impulse current generating unit, the surge arrester fixing unit, the multi-dimensional monitoring unit, and the data acquisition and analysis unit.

[0007] Further, the step of testing the surge arrester based on the test unit, collecting the surge arrester test parameters, and determining the test time interval based on the surge arrester test parameters includes: The surge arrester test parameters include: maximum temperature rise after the first lightning strike, cooling rate after the first lightning strike, ambient temperature of the surge arrester, and cyclic cooling rate. The settling time after the first lightning strike is determined based on the maximum temperature rise after the first lightning strike and the cooling rate after the first lightning strike. The cyclic test interval is determined based on the ambient temperature of the surge arrester and the cyclic cooling rate.

[0008] Furthermore, the current-carrying capacity of the surge arrester is determined based on the voltage change before and after the lightning strike, the leakage current increase factor, and a preset threshold, and the determination result is obtained, including: If the surge arrester is struck by lightning at least four times, the voltage change is less than or equal to a first voltage threshold, and the leakage current increase factor is less than or equal to a first increase factor threshold, then it is determined to be a first-level current-carrying device. If the surge arrester is struck by lightning at least three times, the voltage change is less than or equal to the second voltage threshold, and the leakage current increase factor is less than or equal to the second increase factor threshold, then it is determined to be a secondary current-carrying device. If the surge arrester is struck by lightning at least twice, the voltage change is less than or equal to the third voltage threshold, and the leakage current increase factor is less than or equal to the third increase factor threshold, then it is determined to be a level three current-carrying device.

[0009] This disclosure also provides a surge arrester current-carrying test system, including: The determination module is used to acquire multiple lightning strike parameters, construct a combined test sequence of the first lightning strike and multiple subsequent lightning strikes based on the multiple lightning strike parameters, and determine the peak lightning current and lightning strike time interval based on the combined test sequence. A construction module is used to determine lightning test parameters based on the peak lightning current and the lightning time interval, and to construct a test unit based on the lightning test parameters; The acquisition module is used to test the surge arrester based on the test unit, acquire the surge arrester test parameters, and determine the test time interval based on the surge arrester test parameters; The determination module is used to test the surge arrester based on the test unit and the test time interval, obtain the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike, and determine the failure of the surge arrester based on the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike and a preset threshold, and obtain the determination result.

[0010] Furthermore, the building module is specifically used for: The rated output current of the impulse current generator is determined by the peak value of the lightning strike current. The damping resistance is determined by the peak value of the lightning strike current and the residual voltage of the surge arrester; The grounding resistance limit is determined by the peak value of the lightning current and the voltage to ground of the surge arrester. The test unit is constructed based on the rated output current of the impulse current generator, the damping resistor, and the grounding resistance limit. The test unit includes: the impulse current generating unit, the surge arrester fixing unit, the multi-dimensional monitoring unit, and the data acquisition and analysis unit.

[0011] Furthermore, the acquisition module is specifically used for: The surge arrester test parameters include: maximum temperature rise after the first lightning strike, cooling rate after the first lightning strike, ambient temperature of the surge arrester, and cyclic cooling rate. The settling time after the first lightning strike is determined based on the maximum temperature rise after the first lightning strike and the cooling rate after the first lightning strike. The cyclic test interval is determined based on the ambient temperature of the surge arrester and the cyclic cooling rate.

[0012] Furthermore, the determination module is specifically used for: If the surge arrester is struck by lightning at least four times, the voltage change is less than or equal to a first voltage threshold, and the leakage current increase factor is less than or equal to a first increase factor threshold, then it is determined to be a first-level current-carrying device. If the surge arrester is struck by lightning at least three times, the voltage change is less than or equal to the second voltage threshold, and the leakage current increase factor is less than or equal to the second increase factor threshold, then it is determined to be a secondary current-carrying device. If the surge arrester is struck by lightning at least twice, the voltage change is less than or equal to the third voltage threshold, and the leakage current increase factor is less than or equal to the third increase factor threshold, then it is determined to be a level three current-carrying device.

[0013] This disclosure also provides a computer device, including a memory and a processor, wherein the memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the steps of the surge arrester current-carrying test method.

[0014] This disclosure also provides a computer-readable storage medium storing computer-readable instructions, which, when executed by a processor, implement the steps of the surge arrester current-carrying test method.

[0015] The technical solution provided in this disclosure has the following advantages compared with the prior art: By acquiring multiple lightning strike parameters, a lightning strike test sequence is constructed based on these parameters, and the peak lightning current and lightning strike time interval are determined based on the test sequence. Lightning strike test parameters are then determined based on the peak lightning current and lightning strike time interval, and a test unit is constructed based on these parameters. The surge arrester is then tested using the test unit, and its test parameters are collected. The test time interval is then determined based on these parameters. The surge arrester is then tested again using the test unit and the test time interval, acquiring the voltage change and leakage current increase factor before and after the lightning strike. Based on the voltage change, leakage current increase factor, and preset threshold, the surge arrester's current carrying capacity is determined, and the determination result is obtained. This achieves implicit detection of the surge arrester and improves the effectiveness of the test. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the surge arrester current-carrying test method provided in the embodiments of this disclosure; Figure 2 A schematic diagram of a method for constructing a test unit provided in an embodiment of this disclosure; Figure 3 A schematic diagram of a surge arrester current-carrying test system provided in an embodiment of this disclosure. Detailed Implementation

[0019] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0020] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0021] Figure 1 This is a schematic diagram of the surge arrester current-carrying test method provided in the embodiments of this disclosure; as shown Figure 1 As shown, this disclosure provides a method for testing the current carrying capacity of a surge arrester, including: Step S1: Obtain multiple lightning strike parameters, construct a combined test sequence of the first lightning strike and multiple subsequent lightning strikes based on the multiple lightning strike parameters, and determine the peak lightning current and lightning strike time interval based on the combined test sequence; In this embodiment, multiple lightning strike parameters are acquired because surge arresters are subjected to not only a single lightning strike in actual operation, but also a possible initial lightning strike and multiple subsequent lightning strikes in combination. By acquiring lightning strike parameters, including lightning intensity, number of lightning strikes, time interval between adjacent lightning strikes, terrain correction coefficient, aging correction coefficient, and regional thunderstorm intensity coefficient, a lightning strike test sequence is constructed to ensure that the test process matches the timing and intensity of multiple lightning strikes in the actual power grid environment.

[0022] Furthermore, by constructing a test sequence, the peak current and time interval of each lightning strike can be calculated. By comprehensively considering various influencing factors through quantitative formulas, the multi-dimensional characteristics of actual lightning strikes can be reflected in the experiment. At the same time, by calculating the peak current and time interval in advance, accurate input parameters can be provided for subsequent test unit design and system construction.

[0023] Step S2: Determine the lightning strike test parameters based on the peak lightning current and the lightning strike time interval, and construct a test unit based on the lightning strike test parameters; In this embodiment, lightning strike test parameters are further determined by the peak lightning current and lightning strike time interval, and a test unit is constructed. The lightning strike test parameters include the rated output current of the impulse current generator, the series damping resistor, the grounding resistance limit, the clamp angle of the fixing unit, and the diameter of the equalizing ring, etc. The test unit consists of an impulse current generating unit, a complete surge arrester fixing unit, a multi-dimensional monitoring unit, and a data acquisition and analysis unit. By using the peak lightning current as a reference, the impulse current generator is designed to ensure that the output current can cover the most extreme lightning strike conditions. The time interval parameter is used to determine the timing control logic of the test system, so that the applied lightning strike can simulate the actual lightning strike interval within a short time without causing test errors. Simultaneously, the multi-dimensional monitoring unit can achieve synchronous acquisition of current, voltage, temperature, and partial discharge, thereby ensuring accurate recording and real-time feedback of each test parameter during the experiment, and ensuring that the test system can fully cover the operating limits of the surge arrester.

[0024] Figure 2 This is a schematic diagram of the method for constructing a test unit provided in an embodiment of this disclosure; as shown Figure 2 As shown, specifically, step S2, determining the lightning strike test parameters based on the peak lightning current and the lightning strike time interval, and constructing a test unit based on the lightning strike test parameters, includes: step S21, determining the rated output current of the impulse current generator through the peak lightning current; step S22, determining the damping resistance through the peak lightning current and the residual voltage of the surge arrester; step S23, determining the grounding resistance limit through the peak lightning current and the voltage to ground of the surge arrester; step S24, constructing a test unit based on the rated output current of the impulse current generator, the damping resistance, and the grounding resistance limit. The test unit includes: an impulse current generation unit, a surge arrester fixing unit, a multi-dimensional monitoring unit, and a data acquisition and analysis unit.

[0025] In this embodiment, the peak value of the lightning current and the lightning time interval are used to determine the test parameters, and a test unit for testing the current carrying capacity of the entire surge arrester is constructed. The rated output current of the impulse current generator can be determined by the peak value of the lightning current, ensuring that the test system can apply a lightning current greater than the actual possible lightning current to cover the limit state of the surge arrester's withstand capacity, thereby ensuring that the experimental data can reflect the current carrying performance of the surge arrester under the most severe lightning conditions.

[0026] Meanwhile, by calculating the damping resistance by comparing the peak value of the lightning strike current with the residual voltage of the surge arrester, the overshoot of the circuit voltage can be effectively controlled when the current is applied, ensuring that the test voltage waveform meets the preset standard and preventing non-lightning strike damage to the surge arrester during the experiment.

[0027] By combining the peak lightning current with the arrester's allowable voltage to ground, the grounding resistance limit is determined to ensure that the grounding conditions of the entire test system meet safety regulations. This also guarantees the smooth flow of lightning current and avoids measurement errors or localized overheating due to poor grounding. This ensures that the applied lightning current in the experiment matches the actual lightning strike conditions. Furthermore, by appropriately setting the damping resistor and grounding conditions, the current waveform and loop safety can be controlled, improving data accuracy.

[0028] Step S3: Test the surge arrester based on the test unit, collect the surge arrester test parameters, and determine the test time interval based on the surge arrester test parameters; In this embodiment, the test unit simulates the initial lightning strike and subsequent strikes, ensuring that the surge arrester can withstand multiple high-current impacts in a short period. Simultaneously, a multi-dimensional monitoring unit accurately records the surge arrester's voltage response, leakage current, temperature changes, and partial discharge. The collected data is used to evaluate the surge arrester's dynamic performance under multiple lightning strikes, and by analyzing temperature rise and cooling characteristics, the required rest and cyclic test intervals between subsequent lightning strikes are determined, ensuring that the surge arrester's state closely approximates the cooling conditions of the actual operating environment at the time of each lightning strike. Dynamically determining the test time interval avoids unrealistic thermal effects caused by excessively rapid accumulation of lightning strikes. Furthermore, the collected test parameters provide quantitative basis for subsequent failure determination, making the assessment of latent failures and current carrying capacity more accurate.

[0029] Specifically, in step S3, the surge arrester is tested based on the test unit, the surge arrester test parameters are collected, and the test time interval is determined based on the surge arrester test parameters, including: the surge arrester test parameters include: the maximum temperature rise after the first lightning strike, the cooling rate after the first lightning strike, the ambient temperature of the surge arrester, and the cyclic cooling rate; the settling time after the first lightning strike is determined based on the maximum temperature rise after the first lightning strike and the cooling rate after the first lightning strike; and the cyclic test interval is determined based on the ambient temperature of the surge arrester and the cyclic cooling rate.

[0030] In this embodiment, the maximum temperature rise after the first lightning strike and the cooling rate of the surge arrester after the first lightning strike are recorded. These two parameters are used to calculate the resting time after the first lightning strike to ensure that the surge arrester can dissipate heat and return to a state close to the ambient temperature before being subjected to subsequent lightning strikes, thereby avoiding the heat accumulation effect from having a misleading impact on the test results.

[0031] Meanwhile, by monitoring ambient temperature and cyclic cooling rate, the cyclic test interval can be dynamically determined, ensuring that the interval between each lightning strike meets the thermal balance requirements of the surge arrester under natural cooling conditions. Furthermore, parameters such as current, voltage, temperature, and partial discharge collected during the test provide fundamental data for evaluating the performance changes of the surge arrester under continuous lightning strikes. This allows the test to not only reflect the transient current-carrying capacity of the surge arrester but also to capture latent performance degradation, such as increased leakage current or elevated residual voltage—potential latent failure indicators. Ensuring that the conditions of multiple lightning strike tests closely resemble actual operating conditions while avoiding unrealistic heat accumulation caused by excessively short lightning strike intervals results in more accurate and reliable test data.

[0032] Step S4: Test the surge arrester based on the test unit and test time interval to obtain the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike. Based on the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike and the preset threshold, determine the current carrying capacity of the surge arrester and obtain the determination result.

[0033] In this embodiment, by comparing multi-dimensional indicators such as U1mA voltage, leakage current increment, tanδ, and partial discharge quantity before and after a lightning strike, it can be determined whether the surge arrester has experienced direct failure (such as casing rupture, valve plate temperature exceeding the limit, current cutoff, etc.) or latent failure (such as electrical performance degradation, leakage current increase exceeding the threshold). By comparing with preset level standards, the surge arrester is classified into Class I, Class II, or Class III current-carrying levels. Through quantitative and multi-dimensional data analysis, the performance of the surge arrester is evaluated, enabling the identification of not only obvious damage but also potential latent degradation, thus providing important basis for product improvement and operation and maintenance.

[0034] Specifically, in step S4, based on the voltage change, leakage current growth factor, and preset threshold of the surge arrester before and after a lightning strike, the current carrying level of the surge arrester is determined, and the determination result is obtained, including: if the surge arrester is struck by lightning at least four times, the voltage change is less than or equal to the first voltage threshold, and the leakage current growth factor is less than or equal to the first growth factor threshold, it is determined to be a level one current carrying device; if the surge arrester is struck by lightning at least three times, the voltage change is less than or equal to the second voltage threshold, and the leakage current growth factor is less than or equal to the second growth factor threshold, it is determined to be a level two current carrying device; if the surge arrester is struck by lightning at least twice, the voltage change is less than or equal to the third voltage threshold, and the leakage current growth factor is less than or equal to the third growth factor threshold, it is determined to be a level three current carrying device.

[0035] In this embodiment, by analyzing the voltage change and leakage current increase factor of the surge arrester before and after a lightning strike, and combining it with a preset threshold, the current carrying capacity of the surge arrester is determined, which directly determines the classification of the surge arrester's current carrying capacity.

[0036] The surge arrester's U1mA voltage change and leakage current increment before and after a lightning strike are compared with a set threshold, and the current carrying capacity is determined by comprehensively considering the number of lightning strikes and performance changes. If the surge arrester withstands at least four lightning strikes, and the voltage change is less than or equal to the first voltage threshold and the leakage current increase does not exceed the first increase multiple threshold, it is determined to be a Class 1 current carrying capacity, indicating that the surge arrester has extremely high lightning strike withstand capability and can meet harsh operating conditions. If the surge arrester withstands at least three lightning strikes and the voltage and leakage current changes within the second threshold range, it is determined to be a secondary current-carrying arrester, indicating that the surge arrester still has good lightning protection capability during normal operation, but there is a certain margin decrease under extreme conditions. If a surge arrester withstands at least two lightning strikes and the current change remains within the third threshold range, it is classified as a Class III current-carrying arrester. This indicates that the arrester can still carry current under multiple lightning strikes, but its performance is approaching its design limit, requiring attention to its service life and maintenance cycle. Classification reflects the performance status of the surge arrester under multiple lightning strikes, enabling the detection of both direct failures and latent degradation.

[0037] Among some possible implementation methods, a method for testing the lightning strike high current carrying capacity of the entire surge arrester of an ungrounded transmission line considering multiple lightning strikes includes the following steps: Determine the parameters of multiple lightning strikes: Construct a test sequence of "1 initial lightning strike + N subsequent lightning strikes" (N≥1), calculate key parameters using quantitative formulas, with an interval of 30-300ms between adjacent lightning strikes; Quantitative formula: Peak current of the first lightning strike: ; In the formula: The peak value of the first lightning strike current (kA); This is the standard value for a grounded line; (1.2-1.3) represents the groundless current gain coefficient; (Mountainous areas 1.1-1.2, plains 1.0-1.05, hilly areas 1.05-1.1) are terrain correction factors; (1.1 for ≥5 years of operation, 1.0 for <5 years) is the aging correction factor.

[0038] Subsequent peak lightning current: ; In the formula: The peak current (kA) of the nth subsequent lightning strike; n is the number of subsequent lightning strikes; (0.7-0.9) is the attenuation coefficient, 0.85-0.9 for strong lightning zones and 0.7-0.8 for ordinary lightning zones.

[0039] Lightning strike interval: ; In the formula: The interval between adjacent lightning strikes (ms); As the reference interval; (0.6-0.8 for thunderstorm days ≥ 40, 1.0-1.2 for thunderstorm days < 40) is the thunderstorm intensity correction factor.

[0040] The test system is constructed, including an impulse current generation unit, a complete surge arrester fixing unit, a multi-dimensional monitoring unit, and a data acquisition and analysis unit. The parameters of each unit are designed using the following formulas: Rated output current of the inrush current generator: (≥200kA); In the formula: This represents the peak value of the first lightning strike current during the test (kA).

[0041] The impulse current generator has a rated voltage ≥500kV, with a 5-10Ω damping resistor in series and a zinc oxide voltage limiting element in parallel; the fixing unit clamp has an inclination angle of 0°-15°, and the equalizing ring diameter is: ( ).

[0042] Damping resistor: (5-10Ω); In the formula: This is the maximum residual voltage (kV) of the surge arrester.

[0043] Grounding resistance limit: (≤0.5Ω); In the formula: The maximum allowable voltage to ground at the grounding terminal is 10% of the rated voltage of the surge arrester.

[0044] The multi-dimensional monitoring unit includes a Rogowski coil, a capacitive voltage divider, etc., and the monitoring accuracy meets the following requirements: , , , ;in, Error in measuring current for the Rogowski coil; The error in measuring voltage using a capacitor voltage divider; and These represent the errors in measuring temperature and measuring charge, respectively.

[0045] Perform time-sequential current flow testing: First, preprocess (appearance, initial performance testing, system debugging), including U1mA (rate of change of 1mA reference voltage after the test), I0.75U, and tanδ (dielectric loss factor) detection; system debugging must meet waveform error requirements. Timing accuracy Apply the first lightning strike + N subsequent lightning strikes, collect data synchronously, and retest after the initial test; key timing parameter formulas: Resting time after the first lightning strike: (≥10s); In the formula: The maximum temperature rise (°C) after the first lightning strike. (5-8℃ / s at 25℃) is the cooling rate.

[0046] After the first lightning strike, the system should be left to stand still for ≥10 seconds, with a cycle test interval of ≥5 minutes, and the cooling effect should meet the requirements. .

[0047] Cyclic test interval: (≥5min); In the formula: Ambient temperature (°C); This refers to the time during which the temperature difference between the sample and the ambient temperature is less than 5°C during the cooling process. ; (10-15℃ / min) is the circulating cooling rate.

[0048] Multi-dimensional Failure Assessment and Classification: Failure is assessed using quantitative thresholds to classify flow levels; Assessment formula: The rate of change of U1mA is given by the following formula: (Latent failure threshold ≥ ±10%) Leakage current growth factor: (Latent failure threshold ≥ 3); In the formula, The rate of change of U1mA; This is the 1mA reference voltage after the test. This is the 1mA reference voltage before the test; This is the leakage current growth factor; and These are the leakage currents before and after the test, respectively.

[0049] Direct failure conditions: casing rupture / explosion / flashover, current cutoff ≥10μs ( Valve plate temperature ≥800℃ ) or outer coat temperature ≥200℃ Latent failure conditions: , tanδ≥0.01 (25℃), partial discharge quantity≥20pC ( ).

[0050] Flow rating: Level 1 (withstands 1+3 lightning strikes) and Level 2 (1+2 times) and Level 3 (1+1 times) and ).

[0051] For example: Determining parameters for multiple lightning strikes: Standard value of the first lightning strike current for a 220kV line with a ground wire. Groundless current gain coefficient (Mountainous area), terrain correction factor aging correction factor (Running for <5 years), according to the formula The peak value of the initial lightning strike current was determined to be 125kA (25 / 100μs waveform).

[0052] Subsequent lightning strike attenuation coefficient (Strong lightning zone), subsequent lightning strikes N=3 times, calculated according to the formula: the current of the first subsequent lightning strike. The second time The 3rd (All waveforms are 1.2 / 50μs).

[0053] Thunderstorm intensity correction factor (Thunderstorm days ≥ 40 days), baseline interval According to the formula The interval between adjacent lightning strikes was determined to be 35ms.

[0054] Setting up a test system: Rated output current of the impulse current generator Based on industry standards, the rated output voltage is 200kA. Take 500kV; damping resistor Based on the requirements, the resistance should be 5Ω; grounding resistance limit. The Ω should be controlled at 0.15Ω.

[0055] Fixed unit fixture tilt angle (Actual installation angle of the line: 8°, correction factor) ); Equalizing ring diameter Take 1.0m.

[0056] The multi-dimensional monitoring unit uses: Rogowski coil (bandwidth DC-100MHz, accuracy ±1%), capacitive voltage divider (voltage ratio 1000:1, accuracy ±2%), K-type thermocouple (range -50℃-1200℃, accuracy ±0.5℃), high-definition high-speed camera (1000fps), and partial discharge detector (sensitivity ≤1pC) to ensure that the monitoring accuracy meets quantitative requirements.

[0057] The data acquisition card has a sampling rate of 1GS / s and a resolution of 16 bits. The analysis software supports waveform storage, parameter calculation, and trend analysis, and can automatically generate test reports.

[0058] Perform time-sequential current carrying test: In the preprocessing stage, check that there are no cracks in the surge arrester housing and no deformation in the equalizing ring. Detect the initial U1mA=275kV, I0.75U=12μA, and tanδ=0.006 (25℃); debug the system to ensure that the waveform error is ≤±5% and the timing control accuracy is ≤±1ms.

[0059] An initial lightning strike (125 kA, 25 / 100 μs) was applied for 200 μs, and data was collected simultaneously to monitor the maximum temperature rise. According to the formula (at 25℃) Let it stand for 10 seconds.

[0060] Three subsequent lightning strikes (110kA, 96.8kA, and 85.18kA, all at 1.2 / 50μs) were applied sequentially at 35ms intervals, each lasting 100μs, with data collected simultaneously; this test was repeated three times, with ambient temperature... , , According to the formula The cooling effect was verified at 5-minute intervals. It meets the requirements.

[0061] Let stand for 30 minutes after testing. , According to the formula (Take 30 minutes to ensure stability), retest U1mA=272kV, I0.75U=18μA, tanδ=0.007, partial discharge quantity 8pC, no abnormal appearance.

[0062] Failure determination and severity classification: Calculation of U1mA change rate ( : 1mA reference voltage change rate, in percentage; 272kV, 275kV: 1mA reference voltage U1mA before and after the test, in kilovolts (kV), respectively; leakage current increase factor. ( : 0.75U1mA leakage current growth factor, unitless; 18μA, 12μA: leakage current I0.75U before and after the test, respectively, in microamps (μA). Neither of them reached the failure threshold, and they withstood "1 first lightning strike + 3 subsequent lightning strikes" (number of lightning strikes, unitless), which meets the first-level current carrying capacity standard. Therefore, the current carrying capacity of the surge arrester is deemed to be up to standard.

[0063] Figure 3 This is a schematic diagram of the surge arrester current-carrying test system provided in the embodiments of this disclosure; as shown. Figure 3 As shown, this disclosure also provides a surge arrester current-carrying test system, comprising: The determination module 401 is used to acquire multiple lightning strike parameters, construct a combined test sequence of the first lightning strike and multiple subsequent lightning strikes based on the multiple lightning strike parameters, and determine the peak lightning current and lightning strike time interval based on the combined test sequence; the construction module 402 is used to determine the lightning strike test parameters based on the peak lightning current and lightning strike time interval, and construct a test unit based on the lightning strike test parameters; the acquisition module 403 is used to test the surge arrester based on the test unit, acquire the surge arrester test parameters, and determine the test time interval based on the surge arrester test parameters; the judgment module 404 is used to test the surge arrester based on the test unit and the test time interval, acquire the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike, and determine the failure of the surge arrester based on the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike and a preset threshold, and obtain the judgment result.

[0064] In some possible implementations, a module is constructed specifically for: determining the rated output current of the impulse current generator based on the peak value of the lightning current; determining the damping resistance based on the peak value of the lightning current and the residual voltage of the surge arrester; determining the grounding resistance limit based on the peak value of the lightning current and the voltage to ground of the surge arrester; and constructing a test unit based on the rated output current of the impulse current generator, the damping resistance, and the grounding resistance limit. The test unit includes: an impulse current generation unit, a surge arrester fixing unit, a multi-dimensional monitoring unit, and a data acquisition and analysis unit.

[0065] In some possible implementations, the acquisition module is specifically used to: acquire surge arrester test parameters including: maximum temperature rise after the first lightning strike, cooling rate after the first lightning strike, ambient temperature of the surge arrester, and cyclic cooling rate; determine the settling time after the first lightning strike based on the maximum temperature rise after the first lightning strike and the cooling rate after the first lightning strike; and determine the cyclic test interval based on the ambient temperature of the surge arrester and the cyclic cooling rate.

[0066] In some possible implementations, the determination module is specifically used to: determine that the surge arrester is a first-level current-carrying device if it is struck by lightning at least four times, the voltage change is less than or equal to a first voltage threshold, and the leakage current growth factor is less than or equal to a first growth factor threshold; determine that the surge arrester is a second-level current-carrying device if it is struck by lightning at least three times, the voltage change is less than or equal to a second voltage threshold, and the leakage current growth factor is less than or equal to a second growth factor threshold; and determine that the surge arrester is a third-level current-carrying device if it is struck by lightning at least twice, the voltage change is less than or equal to a third voltage threshold, and the leakage current growth factor is less than or equal to a third growth factor threshold.

[0067] This disclosure also provides a computer device, including a memory and a processor, wherein the memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the steps of a surge arrester current-carrying test method.

[0068] The computer device includes a memory, a processor, and a network interface that are interconnected via a system bus. It should be noted that not all of the shown components are required; more or fewer components may be implemented instead. Those skilled in the art will understand that the computer device described herein is a device capable of automatically performing numerical calculations and / or information processing according to pre-set or stored instructions, and its hardware includes, but is not limited to, microprocessors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), embedded devices, etc.

[0069] The computer device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The computer device can interact with the user via a keyboard, mouse, remote control, touchpad, or voice control.

[0070] The memory includes at least one type of readable storage medium, including flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, disk, optical disk, etc. In some embodiments, the memory may be an internal storage unit of the computer device, such as the hard disk or RAM of the computer device. In other embodiments, the memory may also be an external storage device of the computer device, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the computer device. Of course, the memory may include both internal storage units and external storage devices of the computer device. In this embodiment, the memory is typically used to store the operating system and various application software installed on the computer device, such as program code for real-time data processing methods. In addition, the memory may also be used to temporarily store various types of data that have been output or will be output.

[0071] In some embodiments, the processor may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. The processor is typically used to control the overall operation of the computer device. In this embodiment, the processor is used to run program code stored in the memory or process data, for example, to run the program code of the method.

[0072] The network interface may include a wireless network interface or a wired network interface, which is typically used to establish communication connections between the computer device and other electronic devices.

[0073] This disclosure also provides a computer-readable storage medium storing computer-readable instructions, which, when executed by a processor, implement the steps of a surge arrester current-carrying test method.

[0074] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this disclosure, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this disclosure.

[0075] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0076] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for testing the current carrying capacity of a surge arrester, characterized in that, include: Obtain multiple lightning strike parameters, construct a combined test sequence of the first lightning strike and multiple subsequent lightning strikes based on the multiple lightning strike parameters, and determine the peak lightning current and lightning strike time interval based on the combined test sequence; The lightning strike test parameters are determined based on the peak lightning current and the lightning strike time interval, and a test unit is constructed based on the lightning strike test parameters; The surge arrester is tested using the test unit, the surge arrester test parameters are collected, and the test time interval is determined based on the surge arrester test parameters. The surge arrester is tested based on the test unit and the test time interval to obtain the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike. Based on the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike and a preset threshold, the current carrying capacity of the surge arrester is determined, and the determination result is obtained.

2. The surge arrester current-carrying test method according to claim 1, characterized in that, The process of determining lightning strike test parameters based on the peak lightning current and the lightning strike time interval, and constructing a test unit based on the lightning strike test parameters, includes: The rated output current of the impulse current generator is determined by the peak value of the lightning strike current. The damping resistance is determined by the peak value of the lightning strike current and the residual voltage of the surge arrester; The grounding resistance limit is determined by the peak value of the lightning current and the voltage to ground of the surge arrester. The test unit is constructed based on the rated output current of the impulse current generator, the damping resistor, and the grounding resistance limit. The test unit includes: the impulse current generating unit, the surge arrester fixing unit, the multi-dimensional monitoring unit, and the data acquisition and analysis unit.

3. The surge arrester current-carrying test method according to claim 1, characterized in that, The process of testing the surge arrester based on the test unit, collecting the surge arrester test parameters, and determining the test time interval based on the surge arrester test parameters includes: The surge arrester test parameters include: maximum temperature rise after the first lightning strike, cooling rate after the first lightning strike, ambient temperature of the surge arrester, and cyclic cooling rate. The settling time after the first lightning strike is determined based on the maximum temperature rise after the first lightning strike and the cooling rate after the first lightning strike. The cyclic test interval is determined based on the ambient temperature of the surge arrester and the cyclic cooling rate.

4. The surge arrester current-carrying test method according to claim 1, characterized in that, The current-carrying capacity of the surge arrester is determined based on the voltage change before and after the lightning strike, the leakage current increase factor, and a preset threshold, and the determination result is obtained, including: If the surge arrester is struck by lightning at least four times, the voltage change is less than or equal to a first voltage threshold, and the leakage current increase factor is less than or equal to a first increase factor threshold, then it is determined to be a first-level current-carrying device. If the surge arrester is struck by lightning at least three times, the voltage change is less than or equal to the second voltage threshold, and the leakage current increase factor is less than or equal to the second increase factor threshold, then it is determined to be a secondary current-carrying device. If the surge arrester is struck by lightning at least twice, the voltage change is less than or equal to the third voltage threshold, and the leakage current increase factor is less than or equal to the third increase factor threshold, then it is determined to be a level three current-carrying device.

5. A surge arrester current-carrying test system, characterized in that, include: The determination module is used to acquire multiple lightning strike parameters, construct a combined test sequence of the first lightning strike and multiple subsequent lightning strikes based on the multiple lightning strike parameters, and determine the peak lightning current and lightning strike time interval based on the combined test sequence. A construction module is used to determine lightning test parameters based on the peak lightning current and the lightning time interval, and to construct a test unit based on the lightning test parameters; The acquisition module is used to test the surge arrester based on the test unit, acquire the surge arrester test parameters, and determine the test time interval based on the surge arrester test parameters; The determination module is used to test the surge arrester based on the test unit and the test time interval, obtain the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike, and determine the failure of the surge arrester based on the voltage change and leakage current increase factor of the surge arrester before and after the lightning strike and a preset threshold, and obtain the determination result.

6. The surge arrester current-carrying test system according to claim 5, characterized in that, The building module is specifically used for: The rated output current of the impulse current generator is determined by the peak value of the lightning strike current. The damping resistance is determined by the peak value of the lightning strike current and the residual voltage of the surge arrester; The grounding resistance limit is determined by the peak value of the lightning current and the voltage to ground of the surge arrester. The test unit is constructed based on the rated output current of the impulse current generator, the damping resistor, and the grounding resistance limit. The test unit includes: the impulse current generating unit, the surge arrester fixing unit, the multi-dimensional monitoring unit, and the data acquisition and analysis unit.

7. The surge arrester current-carrying test system according to claim 5, characterized in that, The acquisition module is specifically used for: The surge arrester test parameters include: maximum temperature rise after the first lightning strike, cooling rate after the first lightning strike, ambient temperature of the surge arrester, and cyclic cooling rate. The settling time after the first lightning strike is determined based on the maximum temperature rise after the first lightning strike and the cooling rate after the first lightning strike. The cyclic test interval is determined based on the ambient temperature of the surge arrester and the cyclic cooling rate.

8. The surge arrester current-carrying test system according to claim 5, characterized in that, The determination module is specifically used for: If the surge arrester is struck by lightning at least four times, the voltage change is less than or equal to a first voltage threshold, and the leakage current increase factor is less than or equal to a first increase factor threshold, then it is determined to be a first-level current-carrying device. If the surge arrester is struck by lightning at least three times, the voltage change is less than or equal to the second voltage threshold, and the leakage current increase factor is less than or equal to the second increase factor threshold, then it is determined to be a secondary current-carrying device. If the surge arrester is struck by lightning at least twice, the voltage change is less than or equal to the third voltage threshold, and the leakage current increase factor is less than or equal to the third increase factor threshold, then it is determined to be a level three current-carrying device.

9. A computer device, characterized in that, It includes a memory and a processor, wherein the memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the steps of the surge arrester current-carrying test method as described in any one of claims 1 to 4.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-readable instructions, which, when executed by a processor, implement the steps of the surge arrester current-carrying test method as described in any one of claims 1 to 4.

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