Method and system for detecting insulation defects of a gas-insulated switchgear

Abstract

The application relates to the technical field of power equipment detection, and discloses a method and system for detecting insulation defects of gas insulated switchgear, which comprises the following steps: through the synergistic effect of short-wave irradiation and step voltage, the discharge process of the insulation defect is actively excited, and the passive waiting is replaced by active excitation, the problem of the detection blind area caused by the insufficient natural electron yield of the micro air gap defect is effectively solved, the discharge activity index of multi-parameter fusion overcomes the detection deviation problem caused by the single pulse misjudgment and the strong signal randomness, the intelligent application of the step voltage shortens the detection time, ensures the sufficient capture of the defect discharge characteristics, realizes the double improvement of the detection sensitivity and accuracy, significantly reduces the missed detection rate of the micro air gap defect, significantly reduces the deviation between the detection result and the actual value, and greatly shortens the detection time window, fundamentally breaks through the technical bottleneck of the traditional partial discharge detection, and provides reliable technical support for the accurate detection of GIS insulation defects.

Description

Technical Field

[0001] This invention relates to the field of power equipment testing technology, and in particular to a method and system for detecting insulation defects in gas-insulated switchgear. Background Technology

[0002] In power systems, gas-insulated switchgear (GIS) has become a core component of high-voltage, ultra-high-voltage, and extra-high-voltage substations due to its compact structure, high reliability, and strong environmental adaptability. Its safe and stable operation is directly related to the safety of the power grid. However, most failures of large power equipment originate from the gradual degradation of the internal insulation system. Among these failures, sudden short-circuit faults caused by insulator surface flashover or air gap breakdown are the most common type of GIS failure. Partial discharge detection, as the most effective means of detecting insulation defects, faces severe challenges when dealing with insulation defects with tiny air gaps (such as those with a diameter of less than 0.5 mm). The number of gas molecules inside such defects is extremely small, and the initial electron yield under natural radiation is extremely low (less than 1 per cubic millimeter per second). Even if the electric field reaches the critical value (about 25 kV / cm·atm), the generation of the first effective electron may take several hours to several days, resulting in strong randomness in the discharge signal. Single pulses are easily misjudged as electromagnetic interference (such as noise from switching equipment), and intermittent signals in continuous observation are easily attributed to system instability. This makes the false negative rate of traditional detection methods exceed 30%, and the deviation between the detection results and the actual situation exceeds 20%. More importantly, the test time window for conventional partial discharge detection is usually only 1-10 minutes, while the discharge waiting time of tiny air gaps under natural radiation may be as long as tens of thousands of seconds, making it impossible to effectively capture such insulation defects within the standard detection time, forming a serious detection blind zone. Summary of the Invention

[0003] Based on this, it is necessary to propose a method and system for detecting insulation defects in gas-insulated switchgear to address the aforementioned problems. This method effectively solves the detection blind zone problem caused by insufficient natural electron yield in micro-air gap defects, overcomes the detection deviation problems caused by easy misjudgment of single pulses and strong signal randomness, and ensures sufficient capture of defect discharge characteristics while shortening the detection time. It achieves a dual improvement in detection sensitivity and accuracy, significantly reduces the missed detection rate of micro-air gap defects, significantly reduces the deviation between detection results and actual values, and greatly shortens the detection time window. This fundamentally breaks through the technical bottleneck of traditional partial discharge detection and provides reliable technical support for the accurate detection of GIS insulation defects.

[0004] To achieve the above objectives, the present invention provides, in a first aspect, a method for detecting insulation defects in gas-insulated switchgear, the method comprising:

[0005] According to a preset irradiation rate, the insulation defects of the gas-insulated switchgear are subjected to short-wave irradiation and a stepped voltage is applied to obtain the current discharge pulse signal of the insulation defects of the gas-insulated switchgear.

[0006] When the pulse density of the current discharge pulse signal is less than or equal to the pulse density threshold, the discharge activity index is determined based on the maximum pulse peak value, pulse repetition frequency and average pulse energy of the current discharge pulse signal.

[0007] Based on the discharge activity index, the comprehensive detection results of insulation defects in the gas-insulated switchgear are determined.

[0008] Optionally, determining the discharge activity index based on the maximum pulse peak value, pulse repetition frequency, and average pulse energy of the current discharge pulse signal includes:

[0009] Using formula Determine the discharge activity index;

[0010] in, The discharge activity index is... The weighting coefficients for the maximum pulse peak value are: The maximum pulse peak value, The reference maximum pulse peak value, The weighting coefficients are the pulse repetition frequencies. The pulse repetition frequency is... The reference pulse repetition frequency, The weighting coefficients for the average pulse energy are... The average pulse energy is... The reference average pulse energy.

[0011] Optionally, determining the comprehensive detection result of the insulation defect of the gas-insulated switchgear based on the discharge activity index includes:

[0012] If the discharge activity index is less than the first threshold, the comprehensive test result is determined to be good insulation.

[0013] If the discharge activity index is greater than or equal to the first threshold and less than the second threshold, the comprehensive detection result is determined to indicate the presence of a potential defect.

[0014] If the discharge activity index is greater than or equal to the second threshold, the comprehensive detection result is determined to indicate the presence of a hazardous defect.

[0015] Optionally, before the step of short-wave irradiating and applying a stepped voltage to the insulation defects of the gas-insulated switchgear according to a preset irradiation rate, and obtaining the current discharge pulse signal of the insulation defects of the gas-insulated switchgear, the method further includes:

[0016] According to the initial irradiation rate, the insulation defects of the gas-insulated switchgear are subjected to short-wave irradiation and a stepped voltage is applied to obtain the first discharge pulse signal of the insulation defects of the gas-insulated switchgear.

[0017] If the average delay of the first discharge pulse signal is greater than the average delay threshold, the value of the initial irradiation rate is increased by a first preset step size to obtain the first irradiation rate. The value of the initial irradiation rate is then replaced with the value of the first irradiation rate. The steps of applying short-wave irradiation and step voltage to the insulation defect of the gas-insulated switchgear according to the initial irradiation rate and obtaining the first discharge pulse signal of the insulation defect of the gas-insulated switchgear are repeated until the average delay of the first discharge pulse signal is less than or equal to the average delay threshold.

[0018] If the average delay of the first discharge pulse signal is less than or equal to the average delay threshold, and the delay fluctuation coefficient of the discharge pulse signal is greater than a preset percentage, the value of the initial irradiation rate is increased by a second preset step size to obtain a second irradiation rate. The value of the initial irradiation rate is then replaced with the value of the second irradiation rate. The steps of applying short-wave irradiation and a stepped voltage to the insulation defect of the gas-insulated switchgear according to the initial irradiation rate to obtain the first discharge pulse signal of the insulation defect of the gas-insulated switchgear are repeated until the average delay of the first discharge pulse signal is less than or equal to the average delay threshold, and the delay fluctuation coefficient of the first discharge pulse signal is less than or equal to the preset percentage. The initial irradiation rate is then used as the target irradiation rate.

[0019] The preset irradiation rate is determined based on the target irradiation rate.

[0020] Optionally, before irradiating the insulation defects of the gas-insulated switchgear with shortwave radiation and applying a stepped voltage according to the initial irradiation rate to obtain the first discharge pulse signal of the insulation defects of the gas-insulated switchgear, the method further includes:

[0021] Based on the manufacturing process data or historical testing data of the gas-insulated switchgear, determine the estimated air gap size of the insulation defect of the gas-insulated switchgear;

[0022] The initial irradiation rate is determined based on the estimated air gap size.

[0023] Optionally, determining the preset irradiation rate based on the target irradiation rate includes:

[0024] According to the target irradiation rate, the insulation defects of the gas-insulated switchgear are subjected to short-wave irradiation and a stepped voltage is applied. The second discharge pulse signal of the insulation defects of the gas-insulated switchgear is continuously acquired until a second discharge pulse signal of a preset number of power frequency cycles is acquired.

[0025] If the average delay of the second discharge pulse signal for a preset number of power frequency cycles is less than or equal to the average delay threshold, and the delay fluctuation coefficient of the second discharge pulse signal for a preset number of power frequency cycles is less than or equal to the preset percentage, then the target irradiation rate is taken as the preset irradiation rate.

[0026] Optionally, before the step of short-wave irradiating and applying a stepped voltage to the insulation defects of the gas-insulated switchgear according to a preset irradiation rate, and obtaining the current discharge pulse signal of the insulation defects of the gas-insulated switchgear, the method further includes:

[0027] A stepped voltage is applied to the insulation defect of the gas-insulated switchgear to obtain a non-discharge pulse signal of the insulation defect of the gas-insulated switchgear.

[0028] Before determining the discharge activity index based on the maximum pulse peak value, pulse repetition frequency, and average pulse energy of the current discharge pulse signal, the method further includes:

[0029] The discharge pulse threshold is determined based on the baseline voltage of the no-discharge pulse signal;

[0030] The current discharge pulse signal is filtered according to the discharge pulse threshold to obtain the filtered current discharge pulse signal.

[0031] The filtered current discharge pulse signal is used as the current discharge pulse signal.

[0032] Optionally, the method further includes:

[0033] If the pulse density of the current discharge pulse signal is greater than the pulse density threshold, the steps of short-wave irradiating the insulation defect of the gas-insulated switchgear with a preset irradiation rate and applying a stepped voltage to obtain the current discharge pulse signal of the insulation defect of the gas-insulated switchgear are repeated until the pulse density of the current discharge pulse signal is less than or equal to the pulse density threshold.

[0034] Optionally, the method further includes:

[0035] If, in the second discharge pulse signal of the preset number of power frequency cycles, the average time delay of the second discharge pulse signal of at least one power frequency cycle is greater than the average time delay threshold, or the time delay fluctuation coefficient of the second discharge pulse signal of at least one power frequency cycle is greater than the preset percentage, then the step of performing shortwave irradiation and applying stepped voltage to the insulation defect of the gas-insulated switchgear according to the initial irradiation rate to obtain the first discharge pulse signal of the insulation defect of the gas-insulated switchgear is returned, until the average time delay of the second discharge pulse signal of the preset number of power frequency cycles is less than or equal to the average time delay threshold, and the time delay fluctuation coefficient of the second discharge pulse signal of the preset number of power frequency cycles is less than or equal to the preset percentage.

[0036] To achieve the above objectives, the present invention provides, in a second aspect, an insulation defect detection system for gas-insulated switchgear, the system comprising a shortwave radiation source, a high-frequency current sensor, and a processor;

[0037] Both the shortwave radiation source and the high-frequency current sensor are connected to the processor.

[0038] The shortwave radiation source is used to irradiate insulation defects in gas-insulated switchgear with shortwave radiation and apply stepped voltage.

[0039] The high-frequency current sensor is used to collect discharge pulse signals;

[0040] The processor is used to execute the insulation defect detection method for gas-insulated switchgear as described in any one of the first aspects;

[0041] The shortwave radiation source includes an X-ray tube, a copper filter with switchable thickness, a high-voltage power supply, and a coupling capacitor; the high-frequency current sensor includes a partial discharge detector and a high-speed acquisition card.

[0042] To achieve the above objectives, the present invention provides, in a third aspect, an insulation defect detection device for gas-insulated switchgear, the device comprising:

[0043] The control and acquisition module is used to irradiate the insulation defects of the gas-insulated switchgear with shortwave radiation and apply a stepped voltage according to a preset irradiation rate, and acquire the current discharge pulse signal of the insulation defects of the gas-insulated switchgear.

[0044] The judgment and determination module is used to determine the discharge activity index based on the maximum pulse peak value, pulse repetition frequency and average pulse energy of the current discharge pulse signal when the pulse density of the current discharge pulse signal is less than or equal to the pulse density threshold.

[0045] The detection result determination module is used to determine the comprehensive detection result of the insulation defects of the gas-insulated switchgear based on the discharge activity index.

[0046] To achieve the above objectives, the present invention provides, in a fourth aspect, a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform an insulation defect detection method for a gas-insulated switchgear as described in any one of the first aspects.

[0047] To achieve the above objectives, the present invention provides a computer device in a fifth aspect, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor causes the processor to perform an insulation defect detection method for a gas-insulated switchgear as described in any one of the first aspects.

[0048] The present invention offers the following advantages: The method involves short-wave irradiation and a stepped voltage applied to the insulation defects of a gas-insulated switchgear according to a preset irradiation rate to obtain the current discharge pulse signal of the insulation defects. Then, when the pulse density of the current discharge pulse signal is less than or equal to a pulse density threshold, a discharge activity index is determined based on the maximum pulse peak value, pulse repetition frequency, and average pulse energy of the current discharge pulse signal. Finally, the comprehensive detection result of the insulation defects of the gas-insulated switchgear is determined based on the discharge activity index. In other words, the discharge process of the insulation defects is actively stimulated through the synergistic effect of short-wave irradiation and stepped voltage. By actively stimulating the discharge instead of passively waiting, this method effectively solves the detection blind zone problem caused by insufficient natural electron yield in micro-air gap defects. The discharge activity index, which integrates multiple parameters, overcomes the detection deviation problems caused by easy misjudgment of single pulses and strong signal randomness. The intelligent application of stepped voltage shortens the detection time while ensuring the full capture of defect discharge characteristics, achieving a dual improvement in detection sensitivity and accuracy. This significantly reduces the missed detection rate of micro-air gap defects, significantly reduces the deviation between detection results and actual values, and greatly shortens the detection time window. It fundamentally breaks through the technical bottleneck of traditional partial discharge detection and provides reliable technical support for the accurate detection of GIS insulation defects. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] in:

[0051] Figure 1 This is a schematic diagram of an insulation defect detection method for a gas-insulated switchgear according to an embodiment of this application;

[0052] Figure 2 This is a schematic diagram of an insulation defect detection system for a gas-insulated switchgear according to an embodiment of this application;

[0053] Figure 3 This is a schematic diagram of the statistical time delay theoretical curve of air gap discharge under natural irradiation conditions in the embodiments of this application;

[0054] Figure 4 This is a schematic diagram of the statistical delay Weibull distribution of spherical air gap discharge in an embodiment of this application;

[0055] Figure 5 This is a schematic diagram of an insulation defect detection device for a gas-insulated switchgear according to an embodiment of this application;

[0056] Figure 6 This is a diagram showing the internal structure of a computer device in some embodiments. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] In power systems, gas-insulated switchgear (GIS) has become a core component of high-voltage, ultra-high-voltage, and extra-high-voltage substations due to its compact structure, high reliability, and strong environmental adaptability. Its safe and stable operation is directly related to the safety of the power grid. However, most failures of large power equipment originate from the gradual degradation of the internal insulation system. Among these failures, sudden short-circuit faults caused by insulator surface flashover or air gap breakdown are the most common type of GIS failure. Partial discharge detection, as the most effective means of detecting insulation defects, faces severe challenges when dealing with insulation defects with tiny air gaps (such as those with a diameter of less than 0.5 mm). The number of gas molecules inside such defects is extremely small, and the initial electron yield under natural radiation is extremely low (less than 1 per cubic millimeter per second). Even if the electric field reaches the critical value (about 25 kV / cm·atm), the generation of the first effective electron may take several hours to several days, resulting in strong randomness in the discharge signal. Single pulses are easily misjudged as electromagnetic interference (such as noise from switching equipment), and intermittent signals in continuous observation are easily attributed to system instability. This makes the false negative rate of traditional detection methods exceed 30%, and the deviation between the detection results and the actual situation exceeds 20%. More importantly, the test time window for conventional partial discharge detection is usually only 1-10 minutes, while the discharge waiting time of tiny air gaps under natural radiation may be as long as tens of thousands of seconds, making it impossible to effectively capture such insulation defects within the standard detection time, forming a serious detection blind zone.

[0059] To address the aforementioned issues, this application proposes a method and system for detecting insulation defects in gas-insulated switchgear. This method effectively solves the detection blind zone problem caused by insufficient natural electron yield in micro-air gap defects, overcomes the issues of misjudgment due to single pulses and strong signal randomness leading to detection deviations, and while shortening the detection time, ensures the full capture of defect discharge characteristics. It achieves a dual improvement in detection sensitivity and accuracy, significantly reducing the missed detection rate of micro-air gap defects, significantly decreasing the deviation between detection results and actual values, and greatly shortening the detection time window. This fundamentally breaks through the technical bottleneck of traditional partial discharge detection, providing reliable technical support for the accurate detection of GIS insulation defects. The specific implementation principle will be described in detail in the following embodiments.

[0060] This application provides a method for detecting insulation defects in gas-insulated switchgear in its first aspect.

[0061] Please see Figure 1 This is a schematic diagram of an insulation defect detection method for a gas-insulated switchgear according to an embodiment of this application. The method includes:

[0062] Step 110: According to the preset irradiation rate, short-wave irradiation and stepped voltage are applied to the insulation defects of the gas-insulated switchgear to obtain the current discharge pulse signal of the insulation defects of the gas-insulated switchgear.

[0063] The preset irradiation rate can be set in advance by the operator based on extensive experience, experiments, or statistics. Of course, it can also be set in advance by the operator according to actual needs.

[0064] It should be noted that the irradiation rate, also known as the dose rate, refers to the radiation dose per unit area per unit time; shortwave irradiation refers to irradiation using high-frequency, short-wavelength electromagnetic radiation; stepped voltage is a voltage output mode, the core of which is that the voltage changes gradually in discrete steps within a set range, rather than being continuously and smoothly adjusted. Each step corresponds to a stable voltage value, the interval between steps can be preset, and the voltage accuracy and stabilization time of each step can be controlled.

[0065] Regarding the voltage range, accuracy, and voltage change rate of the stepped voltage, in some embodiments, this application preferably sets the voltage range of the stepped voltage to 1-50kV, the accuracy to not less than ±0.1kV, and the voltage change rate to 0.5kV / s.

[0066] Regarding the acquisition method of the current discharge pulse signal, in some embodiments, the irradiation rate of the shortwave radiation source can be adjusted according to a preset irradiation rate, and then the shortwave radiation source can be controlled to irradiate the insulation defects of the gas-insulated switchgear with shortwave radiation and apply a stepped voltage to obtain the current discharge pulse signal collected by the high-frequency current sensor.

[0067] Regarding the wavelength and power range of the light source output by the shortwave radiation source, in some embodiments, this application preferably sets the wavelength range of the light source output by the shortwave radiation source to 0.1-20nm and the power range to 1-50W.

[0068] In some embodiments, the irradiance of a shortwave radiation source can be adjusted by regulating the wavelength and / or power of the light source output by the shortwave radiation source.

[0069] Step 120: When the pulse density of the current discharge pulse signal is less than or equal to the pulse density threshold, determine the discharge activity index based on the maximum pulse peak value, pulse repetition frequency and average pulse energy of the current discharge pulse signal.

[0070] The pulse density threshold can be preset by the operator based on extensive experience, experiments, or statistics. Alternatively, it can be preset by the operator according to actual needs.

[0071] Regarding the method for determining the pulse density threshold, in some embodiments, the pulse density of a large number of historical discharge pulse signals can be obtained in advance, and then the average pulse density can be determined. Based on the average pulse density, the pulse density threshold can be determined. Preferably, in this application, the pulse density threshold is set to three times the average pulse density.

[0072] In some embodiments, the weighted coefficient method can be used to determine the discharge activity index based on the maximum pulse peak value, pulse repetition frequency, and average pulse energy of the current discharge pulse signal.

[0073] Regarding the determination of the pulse density, maximum pulse peak value, pulse repetition frequency, and average pulse energy of the current discharge pulse signal, in some embodiments, the quotient between the total number of pulses in the current discharge pulse signal and the sampling duration of the current discharge pulse signal can be used as the pulse density, with units of pulses / s; the largest pulse value in the current discharge pulse signal within the sampling duration can be used as the maximum pulse peak value, with units of mV; the quotient between the total number of pulses and the sampling duration can be used as the pulse density, with units of Hz; and the average pulse energy of each pulse in the current discharge pulse signal can be used as the average pulse energy. Preferably, in this application, the sampling duration of the current discharge pulse signal is set to 10s, that is, the high-frequency current sensor collects the current discharge pulse signal once every 10s.

[0074] In some embodiments, the pulse energy of each pulse in the current discharge pulse signal can be determined using the following formula:

[0075] ;

[0076] in, This represents the pulse energy of the nth pulse in the current discharge pulse signal. This represents the start time of the nth pulse in the current discharge pulse signal. This represents the end time of the nth pulse in the current discharge pulse signal. Let be the voltage applied by the nth pulse in the current discharge pulse signal at time t. This represents the pulse value of the nth pulse in the current discharge pulse signal at time t.

[0077] Step 130: Determine the comprehensive test results of insulation defects in gas-insulated switchgear based on the discharge activity index.

[0078] In some embodiments, the comprehensive test results for insulation defects in gas-insulated switchgear can be determined by comparing the discharge activity index with a preset threshold. The preset threshold can be obtained and set in advance by the operator based on extensive experience, experiments, or statistics. Alternatively, it can be set in advance by the operator according to actual needs.

[0079] In this embodiment, the discharge process of insulation defects is actively stimulated through the synergistic effect of shortwave irradiation and stepped voltage. This active stimulation replaces passive waiting, effectively solving the detection blind zone problem caused by insufficient natural electron yield of micro air gap defects. The discharge activity index, which integrates multiple parameters, overcomes the detection deviation problems caused by easy misjudgment of single pulses and strong signal randomness. The intelligent application of stepped voltage shortens the detection time while ensuring the full capture of defect discharge characteristics, achieving a dual improvement in detection sensitivity and accuracy. This significantly reduces the missed detection rate of micro air gap defects, significantly reduces the deviation between detection results and actual values, and greatly shortens the detection time window. It fundamentally breaks through the technical bottleneck of traditional partial discharge detection and provides reliable technical support for the accurate detection of GIS insulation defects.

[0080] In addition to the aforementioned beneficial effects, this method for detecting insulation defects in gas-insulated switchgear also offers the following advantages: Early fault warning: By accurately detecting minute air gap defects, potential problems can be identified before the fault develops into a severe stage. This provides valuable processing time for power maintenance personnel, allowing them to take targeted maintenance measures, such as timely replacement or repair of defective components, before the fault causes large-scale power outages or other serious consequences, thereby preventing further deterioration of the equipment fault and ensuring the stable operation of the power system; Equipment life assessment assistance: Continuous detection of insulation defects in GIS allows for the accumulation of detection data, which can be used to analyze the aging trend of the equipment's insulation system. Combined with factors such as equipment operating time and environmental conditions, the remaining lifespan of the equipment can be more accurately assessed, providing a scientific basis for equipment upgrades and avoiding damage caused by overuse of equipment. This invention addresses the following issues: First, it improves the reliability and economy of equipment operation by preventing sudden failures. Second, it optimizes maintenance plans. Traditional detection methods have high false negative rates and biases, potentially leading to unreasonable maintenance plans. This can result in either excessively frequent maintenance, wasting resources, or insufficient maintenance, failing to detect potential faults in a timely manner. Third, it enhances grid reliability indicators. As core equipment in high-voltage, ultra-high-voltage, and extra-high-voltage substations, the safe and stable operation of GIS (Gas Insulation System) directly affects grid reliability. Effective detection and handling of insulation defects reduces the probability of equipment failures, thereby improving grid reliability indicators such as power supply reliability rate and average outage time, providing better power security for socio-economic development.

[0081] In one feasible implementation, step 120 in the above embodiment, which determines the discharge activity index based on the maximum pulse peak value, pulse repetition frequency, and average pulse energy of the current discharge pulse signal, includes:

[0082] Using formula Determine the discharge activity index;

[0083] in, It is the discharge activity index. The weighting coefficients are the maximum pulse peak value. The maximum pulse peak value, The reference maximum pulse peak value, These are the weighting coefficients for the pulse repetition frequency. The pulse repetition frequency, The reference pulse repetition frequency, The weighting coefficients are the average pulse energy. The average pulse energy, The reference average pulse energy.

[0084] Among them, the reference maximum pulse peak value, reference pulse repetition frequency, reference average pulse energy, weighting coefficient of maximum pulse peak value, weighting coefficient of pulse repetition frequency, and weighting coefficient of average pulse energy can all be obtained and preset by the operator based on a large amount of experience, experiments, or statistics. Of course, they can also be preset by the operator according to actual needs.

[0085] Regarding the values ​​of the reference maximum pulse peak value, the reference pulse repetition frequency, and the reference average pulse energy, in some embodiments, this application preferably sets the reference maximum pulse peak value to 50mV, the reference pulse repetition frequency to 100Hz, and the reference average pulse energy to 1mJ.

[0086] In some embodiments, the sum of the weighting coefficients for the maximum pulse peak value, the pulse repetition frequency, and the average pulse energy is 1. Preferably, the weighting coefficient for the maximum pulse peak value is set to 0.5, the weighting coefficient for the pulse repetition frequency is set to 0.3, and the weighting coefficient for the average pulse energy is set to 0.2.

[0087] In this embodiment of the application, the discharge activity index is determined by a specific formula, which realizes accurate quantitative evaluation of the discharge characteristics of insulation defects and effectively overcomes the evaluation deviation problem caused by the strong randomness of signals in traditional detection.

[0088] Understandably, this formula introduces three key parameters—maximum pulse peak value, pulse repetition frequency, and average pulse energy—and sets benchmark values ​​and weighting coefficients for each, constructing a multi-dimensional quantitative evaluation model. The benchmark values ​​provide a unified reference standard for different parameters, avoiding evaluation biases caused by equipment differences or environmental factors. The weighting coefficients are allocated differently based on the degree of influence of each parameter on discharge activity, ensuring the accuracy and reliability of the evaluation results. This quantitative evaluation method not only overcomes the problem of easy misjudgment of single pulses in traditional detection but also effectively reduces the impact of signal randomness on the evaluation results through multi-parameter fusion, providing strong support for the accurate detection and condition assessment of insulation defects.

[0089] In one feasible implementation, step 130 in the above embodiment, which determines the comprehensive detection result of insulation defects of the gas-insulated switchgear based on the discharge activity index, includes: determining the comprehensive detection result as good insulation when the discharge activity index is less than a first threshold; determining the comprehensive detection result as having potential defects when the discharge activity index is greater than or equal to the first threshold and less than a second threshold; and determining the comprehensive detection result as having hazardous defects when the discharge activity index is greater than or equal to the second threshold.

[0090] The first and second thresholds can both be obtained and preset by the operator based on extensive experience, experiments or statistics. Of course, they can also be preset by the operator according to actual needs.

[0091] Regarding the values ​​of the first threshold and the second threshold, in some embodiments, this application preferably sets the first threshold to 0.3 and the second threshold to 0.7.

[0092] In this embodiment of the application, the accurate classification and assessment of insulation defect status is achieved by classifying the discharge activity index and threshold, providing a scientific basis for equipment maintenance decisions.

[0093] Understandably, this method refines the comprehensive test results into three levels: good insulation, potential defects, and hazardous defects. A graded evaluation system is constructed by setting a first and second threshold. When the discharge activity index is below 0.3, it is judged as good insulation, indicating that the equipment is in a safe operating state. A value between 0.3 and 0.7 is identified as a potential defect, indicating the need for enhanced monitoring. Values ​​exceeding 0.7 are judged as hazardous defects, requiring immediate action. This graded evaluation mechanism not only overcomes the limitations of the traditional binary judgment of pass / fail in testing methods but also achieves precise differentiation of defect severity through quantitative indicators. This enables maintenance personnel to formulate differentiated maintenance strategies based on different defect levels, optimizing maintenance resource allocation while ensuring safe equipment operation, effectively improving the operation and maintenance efficiency and economy of the power system.

[0094] In one feasible implementation, before step 110 in the above embodiment, which involves short-wave irradiating the insulation defect of the gas-insulated switchgear with a preset irradiation rate and applying a stepped voltage to obtain the current discharge pulse signal of the insulation defect, the method further includes: short-wave irradiating the insulation defect of the gas-insulated switchgear with an initial irradiation rate and applying a stepped voltage to obtain the first discharge pulse signal of the insulation defect; if the average delay of the first discharge pulse signal is greater than the average delay threshold, increasing the value of the initial irradiation rate by a first preset step size to obtain the first irradiation rate, and replacing the value of the initial irradiation rate with the value of the first irradiation rate, and re-executing the process of short-wave irradiating the insulation defect of the gas-insulated switchgear with the initial irradiation rate and applying a stepped voltage to obtain the first discharge pulse signal of the insulation defect; The process of discharging the pulse signal continues until the average delay of the first discharge pulse signal is less than or equal to the average delay threshold. If the average delay of the first discharge pulse signal is less than or equal to the average delay threshold, and the delay fluctuation coefficient of the discharge pulse signal is greater than a preset percentage, the initial irradiation rate is increased by a second preset step size to obtain a second irradiation rate. The initial irradiation rate is then replaced with the second irradiation rate. The process of applying short-wave irradiation and a stepped voltage to the insulation defects of the gas-insulated switchgear according to the initial irradiation rate to obtain the first discharge pulse signal of the insulation defects of the gas-insulated switchgear continues until the average delay of the first discharge pulse signal is less than or equal to the average delay threshold, and the delay fluctuation coefficient of the first discharge pulse signal is less than or equal to a preset percentage. The initial irradiation rate is then used as the target irradiation rate. A preset irradiation rate is determined based on the target irradiation rate.

[0095] The initial irradiation rate, average delay threshold, preset percentage, first preset step size, and second preset step size can all be preset by the operator based on extensive experience, experiments, or statistics. Of course, they can also be preset by the operator according to actual needs.

[0096] Regarding the values ​​of the average delay threshold, preset percentage, first preset step size, and second preset step size, in some embodiments, this application preferably sets the average delay threshold to 60s, the preset percentage to 10%, the first preset step size to 5mR / s, and the second preset step size to 2mR / s.

[0097] Regarding the method for determining the average delay, in some embodiments, the timestamps of each pulse in the first discharge pulse signal are determined throughout the entire process of applying the stepped voltage. Then, based on the timestamps of each pulse in the first discharge pulse signal, the time interval between each adjacent pulse in the first discharge pulse signal is determined. Next, the sum of the time intervals between each adjacent pulse in the first discharge pulse signal is determined. Finally, the quotient between the sum and the total number of pulses in the first discharge pulse signal is taken as the average delay.

[0098] Furthermore, regarding the determination of the delay fluctuation coefficient, in some embodiments, the delay standard deviation is determined based on the time interval between each adjacent pulse in the first discharge pulse signal and the average delay, and then the difference between the delay standard deviation and the average delay is used as the delay fluctuation coefficient.

[0099] Regarding the method for determining the preset irradiation rate, in some embodiments, the target irradiation rate can be used as the preset irradiation rate.

[0100] In other embodiments, when the average delay of the first discharge pulse signal is less than or equal to the average delay threshold and the delay fluctuation coefficient of the first discharge pulse signal is less than or equal to a preset percentage, the initial irradiation rate can be directly used as the target irradiation rate.

[0101] It is important to note that the defect volume of a spherical air gap is proportional to the cube of its diameter. The number of gas molecules in a 2mm diameter air gap is approximately 64 times that of a 0.5mm diameter air gap. Under the same irradiation rate, the initial electron yield of a large-size air gap is much higher than that of a small-size air gap. However, existing detection methods mostly use a fixed irradiation rate (e.g., 2.5mR / s), which leads to over-excitation of large-size air gaps (time delay saturation but reduced pulse height) and under-excitation of small-size air gaps (time delay is still too long). In other words, although existing detection methods have attempted to use short-wave irradiation sources to excite defect discharge, they lack a precise irradiation rate control mechanism for air gaps of different sizes. Traditional detection methods only judge the time delay compression effect by whether a signal is detected, and cannot quantify the reduction magnitude and reliability. Even if the time delay is compressed from 10 hours to 1 minute, if the time delay fluctuation coefficient is greater than a certain percentage (e.g., 50%), the signal may still fail to trigger within the 1-minute window. Furthermore, for every 0.1 atm change in air gap pressure, the critical field strength fluctuates by 5% to 10%, further increasing the complexity of detection. In other words, there is a lack of a quantitative evaluation method for the time delay compression effect.

[0102] In this embodiment, by dynamically adjusting the initial irradiation rate, precise irradiation rate control for air gaps of different sizes is achieved, and the time delay compression effect is quantitatively evaluated. This effectively solves the problems of over-excitation of large-size air gaps and under-excitation of small-size air gaps in traditional detection, while avoiding signal leakage due to time delay fluctuations, thus improving the reliability and accuracy of detection.

[0103] Understandably, this method first ensures that the average delay of the first discharge pulse signal is less than or equal to the average delay threshold by dynamically adjusting the initial irradiation rate, thus avoiding the problem of excessive delay caused by underexcitation of small-sized air gaps. Secondly, when the average delay meets the requirements, the irradiation rate is further adjusted to reduce the delay fluctuation coefficient, ensuring that the signal is stably triggered within the set detection time window, thus overcoming the problem of delay saturation but pulse height reduction caused by overexcitation of large-sized air gaps.

[0104] Furthermore, this method provides a scientific basis for the reliability of detection results by quantifying the time delay compression effect (such as average time delay and time delay fluctuation coefficient), avoiding the limitation of judging the time delay compression effect solely by whether a signal is detected in traditional detection. This precise irradiation rate control mechanism and time delay compression effect evaluation method not only improve the detection sensitivity of air gap defects of different sizes, but also significantly reduce the missed detection rate, providing reliable technical support for the accurate detection of GIS insulation defects.

[0105] In one feasible implementation, before short-wave irradiation and step voltage application are performed on the insulation defects of the gas-insulated switchgear according to the initial irradiation rate in the above embodiments to obtain the first discharge pulse signal of the insulation defects of the gas-insulated switchgear, the method further includes: determining the estimated air gap size of the insulation defects of the gas-insulated switchgear according to the manufacturing process data or historical test data of the gas-insulated switchgear; and determining the initial irradiation rate according to the estimated air gap size.

[0106] Regarding the method for determining the initial irradiation rate, in some embodiments, the initial irradiation rate can be obtained by matching the estimated air gap size with a preset initial irradiation rate table. The preset initial irradiation rate table can be obtained and preset by the operator based on a large amount of experience, experiments or statistics. Of course, it can also be preset by the operator according to actual needs.

[0107] It should be noted that the preset initial irradiation rate table contains a one-to-one matching initial irradiation rate and estimated air gap size.

[0108] In this embodiment, the initial irradiation rate is determined by estimating the air gap size of the insulation defect in the gas-insulated switchgear, thereby achieving accurate pre-setting of the initial irradiation rate and improving detection efficiency and accuracy.

[0109] Understandably, by utilizing manufacturing process data or historical testing data of gas-insulated switchgear to determine the estimated air gap size, and then determining the initial irradiation rate based on the estimated air gap size, a relatively suitable initial irradiation rate can be planned in advance according to the actual situation of the equipment. This avoids the problems that may arise from directly using a fixed irradiation rate, such as over-excitation of large-size air gaps and under-excitation of small-size air gaps. This allows for a more reasonable irradiation rate at the start of testing, thereby achieving the ideal testing state more quickly and effectively improving testing efficiency. It also lays a good foundation for subsequent accurate detection of insulation defects and obtaining reliable test results, further improving the accuracy of testing.

[0110] In one feasible implementation, determining the preset irradiation rate based on the target irradiation rate in the above embodiments includes: applying short-wave irradiation and a stepped voltage to the insulation defects of the gas-insulated switchgear according to the target irradiation rate, continuously acquiring the second discharge pulse signal of the insulation defects of the gas-insulated switchgear until a second discharge pulse signal of a preset number of power frequency cycles is acquired; when the average time delay of the second discharge pulse signal of the preset number of power frequency cycles is less than or equal to the average time delay threshold, and the time delay fluctuation coefficient of the second discharge pulse signal of the preset number of power frequency cycles is less than or equal to a preset percentage, the target irradiation rate is taken as the preset irradiation rate.

[0111] The preset values ​​can be obtained and set in advance by the operator based on a large amount of experience, experiments or statistics. Of course, they can also be set in advance by the operator according to actual needs.

[0112] Regarding the value of the preset value, in some embodiments, this application preferably sets the preset value to 10.

[0113] In this embodiment, the reliability of the preset irradiation rate is ensured through multi-cycle verification, effectively improving the stability and accuracy of detection.

[0114] Understandably, the target irradiation rate is determined as the preset irradiation rate only after continuously acquiring the second discharge pulse signal for a preset number of power frequency cycles and verifying that the average time delay and time delay fluctuation coefficient of all cycles meet the requirements. This multi-cycle verification mechanism effectively avoids the random errors of a single detection, ensuring that the irradiation rate setting can stably adapt to the detection needs under different working conditions. Especially when dealing with small air gap defects, continuous verification for 10 power frequency cycles ensures sufficient acquisition of detection signals, and through quantitative control of the time delay fluctuation coefficient, the detection system can stably capture the defect discharge characteristics, significantly reducing the risk of misjudgment caused by environmental interference or equipment status fluctuations, and providing a more reliable technical guarantee for GIS insulation defect detection.

[0115] In one feasible implementation, before step 110 in the above embodiment, which involves short-wave irradiating the insulation defect of the gas-insulated switchgear with a preset irradiation rate and applying a stepped voltage to obtain the current discharge pulse signal of the insulation defect of the gas-insulated switchgear, the method further includes: applying a stepped voltage to the insulation defect of the gas-insulated switchgear to obtain the no-discharge pulse signal of the insulation defect of the gas-insulated switchgear.

[0116] In step 120 of the above embodiment, before determining the discharge activity index based on the maximum pulse peak value, pulse repetition frequency and average pulse energy of the current discharge pulse signal, the method further includes: determining the discharge pulse threshold based on the baseline voltage of the no discharge pulse signal; filtering the current discharge pulse signal based on the discharge pulse threshold to obtain the filtered current discharge pulse signal; and using the filtered current discharge pulse signal as the current discharge pulse signal.

[0117] Regarding the method for determining the discharge pulse threshold, in some embodiments, the sum of a preset margin and the baseline voltage can be used as the discharge pulse threshold; wherein the preset margin is a random number greater than 0.

[0118] Regarding the method for determining the filtered current discharge pulse signal, in some embodiments, current discharge pulses that are greater than the discharge pulse threshold can be used as the filtered current discharge pulses to obtain the filtered current discharge pulse signal.

[0119] In this embodiment, by dynamically setting the discharge pulse threshold and filtering the signal using the baseline voltage, the interference of electromagnetic interference on the detection results is effectively eliminated, thereby improving the accuracy and reliability of insulation defect detection.

[0120] Understandably, this method first obtains a discharge pulse signal by applying a stepped voltage and extracts its baseline voltage as an environmental noise reference value. Then, a preset margin is superimposed on the baseline voltage to form a dynamic discharge pulse threshold. This threshold can be automatically adjusted according to changes in the equipment's operating environment. Finally, the current discharge pulse signal is filtered through this threshold, retaining only the true discharge signal that exceeds the threshold. This processing method overcomes the limitation of fixed thresholds in traditional detection being easily affected by environmental noise. In particular, it achieves accurate filtering of electromagnetic interference signals such as switching operation noise and radio interference commonly found in GIS equipment through a dynamic threshold mechanism. For example, when the baseline voltage increases due to environmental interference, the threshold is raised synchronously to avoid misjudgment. When changes in equipment status lead to a decrease in noise, the threshold is automatically lowered to prevent missed detection. This provides a clean signal basis for subsequent discharge activity index calculation, significantly improving the sensitivity and accuracy of detecting micro-air gap defects.

[0121] In one feasible implementation, the method in the above embodiments further includes: when the pulse density of the current discharge pulse signal is greater than the pulse density threshold, re-execute the step of short-wave irradiating the insulation defect of the gas-insulated switchgear according to a preset irradiation rate and applying a stepped voltage to obtain the current discharge pulse signal of the insulation defect of the gas-insulated switchgear, until the pulse density of the current discharge pulse signal is less than or equal to the pulse density threshold.

[0122] In this embodiment, by dynamically removing abnormal signal interference, the accuracy and reliability of insulation defect detection results are significantly improved.

[0123] In the embodiments of this application, when the pulse density of the current discharge pulse signal exceeds a preset threshold, a re-detection process is automatically triggered until the signal pulse density drops below the threshold. This closed-loop control mechanism effectively solves the problem of misjudgment caused by abnormal signals (such as sudden equipment vibration, external electromagnetic pulse interference, etc.) in traditional detection. At the same time, by dynamically ensuring that the detection system always works in the best signal acquisition state, it provides a purer data foundation for subsequent discharge activity index calculation. In particular, it can maintain detection accuracy even in complex electromagnetic environments, providing a more reliable technical guarantee for the safe operation of GIS.

[0124] In one feasible implementation, the method in the above embodiment further includes: if, in the second discharge pulse signal of a preset number of power frequency cycles, the average time delay of the second discharge pulse signal of at least one power frequency cycle is greater than the average time delay threshold, or the time delay fluctuation coefficient of the second discharge pulse signal of at least one power frequency cycle is greater than a preset percentage, then the step of performing short-wave irradiation and applying stepped voltage to the insulation defect of the gas-insulated switchgear according to the initial irradiation rate to obtain the first discharge pulse signal of the insulation defect of the gas-insulated switchgear is returned to execution until the average time delay of the second discharge pulse signal of the preset number of power frequency cycles is less than or equal to the average time delay threshold, and the time delay fluctuation coefficient of the second discharge pulse signal of the preset number of power frequency cycles is less than or equal to the preset percentage.

[0125] In this embodiment of the application, the absolute reliability of the irradiation rate setting is ensured through a full-cycle dynamic verification mechanism, fundamentally eliminating the detection blind zone.

[0126] Understandably, implementing dual fault-tolerant control during multi-cycle verification means that if the delay or fluctuation coefficient of any power frequency cycle exceeds the standard, the entire process is immediately re-tested. This zero-tolerance verification mechanism ensures that the final preset irradiation rate can stably excite defect discharge under all operating conditions. Especially when dealing with small air gap defects, even if air gap pressure fluctuations (±0.1 atm causes a 5-10% change in critical field strength) or environmental electromagnetic interference (such as pulse interference generated by substation switch operation) are encountered, the system can still ensure that the defect discharge characteristics are completely captured in each power frequency cycle by dynamically adjusting the irradiation rate. This provides zero-blind-zone insulation detection protection for GIS and significantly improves the safety of power system operation.

[0127] In a second aspect, this application provides an insulation defect detection system for gas-insulated switchgear.

[0128] Please see Figure 2 This is a schematic diagram of an insulation defect detection system for a gas-insulated switchgear according to an embodiment of this application. The system includes a shortwave radiation source 210, a high-frequency current sensor 220, and a processor 230.

[0129] The shortwave radiation source and the high-frequency current sensor are both connected to the processor.

[0130] In one feasible implementation, a shortwave radiation source is used to irradiate insulation defects in a gas-insulated switchgear with shortwave radiation and apply a stepped voltage; a high-frequency current sensor is used to acquire discharge pulse signals; and a processor is used to execute an insulation defect detection method for a gas-insulated switchgear as described in any of the first aspects.

[0131] The shortwave radiation source includes an X-ray tube, a copper filter with switchable thickness, a high-voltage power supply, and a coupling capacitor, while the high-frequency current sensor includes a partial discharge detector and a high-speed acquisition card.

[0132] For the numerical values ​​of some devices, in some embodiments, this application preferably specifies that the tube voltage of the X-ray tube is 150kV and the tube current ranges from 1 to 10mA; the thickness of the switchable copper filter is available in three switchable thicknesses: 2mm, 3.6mm, and 6.0mm; the voltage output range of the high-voltage power supply and coupling capacitor is 0-50kV, the voltage accuracy is ±0.5%, and the boost rate is 0.5kV / s; the sensitivity of the partial discharge detector is 0.01pC, and the noise level is ≤0.3pC; the sampling rate of the high-speed acquisition card is 500MS / s, and the storage depth is 20Mpts.

[0133] The combination of tube current and switchable thickness can achieve multi-gradient control of irradiation rate from 0.5 to 294 mR / s.

[0134] In this embodiment, a modular hardware architecture and multi-gradient control design are used to achieve high precision, high adaptability and high reliability of the insulation defect detection system.

[0135] Understandably, this system employs a modular integrated design of a shortwave radiation source, a high-frequency current sensor, and a processor. The shortwave radiation source, through a combination of an X-ray tube and a switchable thickness copper filter, achieves precise control of the irradiation rate within the range of 0.5-294 mR / s, simultaneously meeting the differentiated excitation requirements of small air gaps (<0.5 mm) and large air gaps (>2 mm). A stepped voltage module (0-50 kV, ±0.5%, and 0.5 kV / s) composed of a high-voltage power supply and coupling capacitors ensures precise control of the electric field strength. The high-frequency current sensor uses a high-speed acquisition card with a sampling rate of 500MS / s and a partial discharge detector with a sensitivity of 0.01pC. Combined with dynamic baseline tracking technology, it can effectively filter out electromagnetic interference such as switching operation noise (>10dB). The processor automatically optimizes the irradiation rate parameters by analyzing the time delay characteristics (average time delay <60s) and fluctuation coefficient (<10%) of the discharge pulse signal in real time. This enables the system to stably capture defect discharge characteristics even under complex working conditions, providing a full-size air gap coverage and high anti-interference insulation detection solution for GIS equipment.

[0136] In some embodiments, to verify the effectiveness of the proposed method for detecting insulation defects in GIS, this application will conduct a series of rigorous comparative tests, the details of which are as follows:

[0137] 1. Test subjects and environment settings:

[0138] In selecting the test objects, we focused on epoxy insulation components commonly used in GIS and prefabricated three spherical air gap defect samples with typical characteristics: Sample A is a small air gap with a diameter of 0.29 mm and a copper plate thickness of 2 mm; Sample B is a medium air gap with a diameter of 0.65 mm and a copper plate thickness of 2 mm; Sample C is a larger air gap with a diameter of 0.65 mm and no copper plate is added.

[0139] The experimental environment was strictly controlled at room temperature of 25°C and standard atmospheric pressure of 760 Torr. To ensure the accuracy of the irradiation rate, film was used for irradiation rate calibration. The film was placed in the output path of the X-ray tube and the adjustable thickness copper filter, and irradiation rates were set to 0.5 mR / s, 5 mR / s, 25 mR / s, and 294 mR / s, respectively. After irradiation for 1 minute at each irradiation rate, the grayscale value was measured using an optical densitometer, and the measured value was calculated by comparing it with the NIST standard dose-grayscale curve, thereby ensuring the accuracy of the irradiation rate data.

[0140] 2. Detailed Workflow:

[0141] Baseline voltage recording and interference elimination: First, using a high-voltage power supply and coupling capacitors, an electric field is applied to the epoxy insulation component by slowly increasing the voltage from 5kV at a rate of 0.5kV / s. During this process, the baseline voltage without discharge pulse signals is carefully recorded. This method effectively eliminates the influence of electromagnetic interference on the test results, laying the foundation for accurate subsequent testing.

[0142] Initial irradiation rate matching: Based on the manufacturing process data or historical test data of the epoxy insulation component, the air gap size is estimated, and then the corresponding initial irradiation rate is matched. This step aims to initially set appropriate X-ray irradiation parameters according to the different characteristics of the air gap, providing reasonable starting conditions for subsequent testing.

[0143] X-ray energy spectrum switching and photoelectric effect triggering: After the X-ray tube is turned on, the energy spectrum is changed by switching between 2mm / 3.6mm / 6.0mm copper filters. When X-ray photons undergo the photoelectric effect with gas molecules such as N2, O2, and CH4 in the gas gap of the epoxy insulation component, the initial electron density rapidly increases from <1 electron / (mm³·s) to several thousand electron / (mm³·s), creating conditions for the subsequent discharge process.

[0144] Pulse signal acquisition and parameter adjustment: A partial discharge detector and a high-speed acquisition card are used to acquire pulse signals in real time. The processor performs rapid calculations on the acquired signals to obtain the average delay and delay fluctuation coefficient. If the average delay > 60 seconds (within a 1-minute test window), the irradiation rate is increased in steps of 5 mR / s; if the delay fluctuation coefficient > 10% (indicating insufficient stability), the irradiation rate is fine-tuned in steps of 2 mR / s. Parameters are continuously adjusted until the average delay < 60 seconds and the fluctuation coefficient < 10%, at which point the optimal irradiation rate is maintained for 3 minutes. If stable discharge pulses are detected for 10 consecutive power frequency cycles (i.e., meeting the conditions of average delay < 60 seconds and fluctuation coefficient < 10), the delay compression is deemed satisfactory. The partial discharge detector and high-speed acquisition card are immediately activated to acquire detailed discharge pulse signals, and the processor performs the detection operation. If the conditions are not met, the parameters are fine-tuned again until they are satisfied.

[0145] 3. Comparative Analysis of Detection Results

[0146] Please see Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the statistical time delay theoretical curve of air gap discharge under natural irradiation conditions in an embodiment of this application. Figure 4 This is a schematic diagram of the statistical time delay Weibull distribution of spherical air gap discharge in an embodiment of this application.

[0147] from Figure 3As can be clearly seen, the theoretical statistical time delay curve for air gap discharge under natural irradiation conditions shows that the theoretical statistical time for a 0.65 mm diameter air gap is tens of thousands of seconds. However, under X-ray irradiation, the time delay is significantly compressed to the tens of seconds level, a compression ratio exceeding three orders of magnitude. For the even smaller 0.29 mm air gap, the statistical time delay is further compressed to around 100 seconds, which initially demonstrates that the method of this application has a significant effect on compressing the statistical time delay of air gap discharge.

[0148] Figure 4 This study visually demonstrates the profound impact of X-ray irradiation on the time delay distribution. Under no X-ray irradiation conditions, the time delay distribution exhibits a highly dispersed state, implying significant uncertainty in discharge time. However, under X-ray irradiation conditions, the time delay distribution becomes significantly more concentrated, and with increasing irradiation rate, the distribution becomes even more compact, and the time delay fluctuation coefficient decreases significantly. This result further validates that the method proposed in this application can effectively improve the distribution characteristics of the air gap discharge time delay and enhance detection stability.

[0149] Comparison of actual test data: Comparative tests were conducted on epoxy insulation components containing air gaps. The results show that under natural irradiation conditions, the average statistical delay of an air gap with a diameter of 0.65 mm is 32,500 seconds, with a fluctuation coefficient of 78.3%. However, after applying the method of this application, the average delay was successfully reduced to 42.7 seconds, and the fluctuation coefficient was reduced to 8.2%. For a tiny air gap with a diameter of 0.29 mm, the average statistical delay under natural irradiation conditions exceeds 100,000 seconds, which is reduced to 98.3 seconds after applying the method of this application, with a fluctuation coefficient of 9.6%. These actual test data strongly demonstrate the superior performance of the method of this application in reducing the statistical delay of air gap discharge and lowering the fluctuation coefficient.

[0150] 4. Verification of key parameters

[0151] The following key points require special attention during the implementation of this application:

[0152] Matching X-ray irradiation rate with air gap size: Precise matching of X-ray irradiation rate and air gap size is crucial. For tiny air gaps with a diameter <0.5 mm, a high irradiation rate (20-294 mR / s) is necessary to effectively compress the statistical time delay. This is because the discharge process in tiny air gaps is relatively weak, requiring higher-energy X-ray irradiation to excite enough electrons, thereby achieving time delay compression.

[0153] Copper filter thickness selection: The thickness of the copper filter should be flexibly adjusted according to the air gap size. For small air gaps, a thinner copper filter (2mm) is preferable, as this retains more low-energy photons and improves ionization efficiency. When low-energy photons interact with gas molecules within the air gap, they are more likely to trigger the photoelectric effect, thereby promoting the discharge process.

[0154] Time delay fluctuation coefficient control: The time delay fluctuation coefficient should be strictly controlled within 10%, which is crucial to ensuring reliable triggering of the discharge signal within the standard test time window. Only with a small time delay fluctuation coefficient can the stability and repeatability of the discharge signal be guaranteed, thereby improving the accuracy of the detection results.

[0155] High voltage application rate control: The high voltage application rate should be controlled at 0.5 kV / s to avoid measurement errors caused by excessively rapid voltage changes. Excessively rapid voltage changes may cause uneven electric field distribution, affecting the discharge process within the air gap and leading to inaccurate measurement results.

[0156] 5. Summary of Test Results

[0157] Test results show that, on typical 0.65mm and 0.29mm spherical air gap samples, the detection method proposed in this application successfully reduced the statistical time delay from tens of thousands of seconds under natural irradiation to tens to hundreds of seconds, a reduction of more than three orders of magnitude. Simultaneously, the time delay fluctuation coefficient was stably controlled within 10%, ensuring reliable triggering and capture of the discharge signal within the standard test time window. This technology significantly improves the detection sensitivity and reliability of latent defects such as micron-level air gaps inside epoxy insulation components, providing effective technical support for the accurate assessment of GIS insulation status and safe operation, and has broad application prospects and significant practical value.

[0158] This application provides, in a third aspect, an insulation defect detection device for gas-insulated switchgear.

[0159] Please see Figure 5 This is a schematic diagram of an insulation defect detection device for a gas-insulated switchgear according to an embodiment of this application. The device 510 includes:

[0160] The control and acquisition module 511 is used to irradiate the insulation defects of the gas-insulated switchgear with shortwave radiation and apply a stepped voltage according to a preset irradiation rate, and acquire the current discharge pulse signal of the insulation defects of the gas-insulated switchgear.

[0161] The judgment and determination module 512 is used to determine the discharge activity index based on the maximum pulse peak value, pulse repetition frequency and average pulse energy of the current discharge pulse signal when the pulse density of the current discharge pulse signal is less than or equal to the pulse density threshold.

[0162] The test result determination module 513 is used to determine the comprehensive test results of insulation defects in gas-insulated switchgear based on the discharge activity index.

[0163] In this embodiment of the application, the relevant contents of the control and acquisition module 511, the judgment and determination module 512, and the detection result determination module 513 can be found in the following references. Figure 1 The contents of the illustrated embodiments will not be repeated here.

[0164] It should be noted that the device 510 of this application also includes other modules. It can be understood that the method of this application and the device 510 have a one-to-one correspondence. Therefore, the other modules of the device 510 of this application are the contents corresponding to the method of this application in the above embodiments.

[0165] In this embodiment, the discharge process of insulation defects is actively stimulated through the synergistic effect of shortwave irradiation and stepped voltage. This active stimulation replaces passive waiting, effectively solving the detection blind zone problem caused by insufficient natural electron yield of micro air gap defects. The discharge activity index, which integrates multiple parameters, overcomes the detection deviation problems caused by easy misjudgment of single pulses and strong signal randomness. The intelligent application of stepped voltage shortens the detection time while ensuring the full capture of defect discharge characteristics, achieving a dual improvement in detection sensitivity and accuracy. This significantly reduces the missed detection rate of micro air gap defects, significantly reduces the deviation between detection results and actual values, and greatly shortens the detection time window. It fundamentally breaks through the technical bottleneck of traditional partial discharge detection and provides reliable technical support for the accurate detection of GIS insulation defects.

[0166] In addition to the aforementioned beneficial effects, the insulation defect detection device for gas-insulated switchgear also has the following advantages: Early fault warning: By accurately detecting minute air gap defects, potential problems can be identified before the fault develops to a serious stage. This provides valuable processing time for power maintenance personnel, allowing them to take targeted maintenance measures, such as timely replacement or repair of defective components, before the fault causes large-scale power outages or other serious consequences, thereby preventing further deterioration of the equipment fault and ensuring the stable operation of the power system; Equipment life assessment assistance: Continuous detection of insulation defects in GIS allows for the accumulation of detection data, which can be used to analyze the aging trend of the equipment insulation system. Combined with factors such as equipment operating time and environmental conditions, the remaining life of the equipment can be more accurately assessed, providing a scientific basis for equipment upgrades and avoiding damage caused by overuse of the equipment. This invention addresses several key aspects of power grid reliability and improves the reliability and economy of equipment operation. Firstly, it addresses the issue of sudden failures caused by GIS (Gas Insulation System) defects. Secondly, it optimizes maintenance plans, as traditional detection devices often have high false negative rates and detection biases, leading to unreasonable maintenance plans. This results in either excessively frequent maintenance, wasting resources, or insufficient maintenance, failing to detect potential faults in a timely manner. Thirdly, it enhances grid reliability indicators, as GIS is a core component of high-voltage, ultra-high-voltage, and extra-high-voltage substations. Its safe and stable operation directly impacts grid reliability. By effectively detecting and addressing insulation defects, the probability of equipment failures is reduced, thereby improving grid reliability indicators such as power supply reliability rate and average outage time, providing a higher quality power guarantee for socio-economic development.

[0167] In a fourth aspect, this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform an insulation defect detection method for a gas-insulated switchgear as described in any of the first aspects.

[0168] This application provides a computer device in a fifth aspect, including a memory and a processor, the memory storing a computer program, which, when executed by the processor, causes the processor to perform an insulation defect detection method for a gas-insulated switchgear as described in any of the first aspects.

[0169] Figure 6 The diagram illustrates the internal structure of a computer device in some embodiments. This computer device may specifically be a terminal, a server, or a gateway. Figure 6 As shown, the computer device includes a processor, memory, and network interface connected via a system bus.

[0170] The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When executed by a processor, this computer program causes the processor to perform the steps in the above method embodiments. The internal memory may also store a computer program, which, when executed by a processor, causes the processor to perform the steps in the above method embodiments. Those skilled in the art will understand that... Figure 6 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0171] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods.

[0172] Any references to memory, storage, database, or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0173] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0174] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for detecting insulation defects in gas-insulated switchgear, characterized in that, The method includes: According to a preset irradiation rate, the insulation defects of the gas-insulated switchgear are subjected to short-wave irradiation and a stepped voltage is applied to obtain the current discharge pulse signal of the insulation defects of the gas-insulated switchgear. When the pulse density of the current discharge pulse signal is less than or equal to the pulse density threshold, the discharge activity index is determined based on the maximum pulse peak value, pulse repetition frequency, and average pulse energy of the current discharge pulse signal. Based on the discharge activity index, the comprehensive detection results of insulation defects in the gas-insulated switchgear are determined; in, The determination of the discharge activity index based on the maximum pulse peak value, pulse repetition frequency, and average pulse energy of the current discharge pulse signal includes: Using formula Determine the discharge activity index; in, The discharge activity index is... The weighting coefficients for the maximum pulse peak value are: The maximum pulse peak value, The reference maximum pulse peak value, The weighting coefficients are the pulse repetition frequencies. The pulse repetition frequency is... The reference pulse repetition frequency, The weighting coefficients for the average pulse energy are... The average pulse energy is... The baseline average pulse energy; Before applying short-wave irradiation and a stepped voltage to the insulation defects of the gas-insulated switchgear according to a preset irradiation rate, and obtaining the current discharge pulse signal of the insulation defects of the gas-insulated switchgear, the method further includes: According to the initial irradiation rate, the insulation defects of the gas-insulated switchgear are subjected to short-wave irradiation and a stepped voltage is applied to obtain the first discharge pulse signal of the insulation defects of the gas-insulated switchgear. If the average delay of the first discharge pulse signal is greater than the average delay threshold, the value of the initial irradiation rate is increased by a first preset step size to obtain the first irradiation rate. The value of the initial irradiation rate is then replaced with the value of the first irradiation rate. The steps of applying short-wave irradiation and step voltage to the insulation defect of the gas-insulated switchgear according to the initial irradiation rate and obtaining the first discharge pulse signal of the insulation defect of the gas-insulated switchgear are repeated until the average delay of the first discharge pulse signal is less than or equal to the average delay threshold. If the average delay of the first discharge pulse signal is less than or equal to the average delay threshold, and the delay fluctuation coefficient of the discharge pulse signal is greater than a preset percentage, the value of the initial irradiation rate is increased by a second preset step size to obtain a second irradiation rate. The value of the initial irradiation rate is then replaced with the value of the second irradiation rate. The steps of applying short-wave irradiation and a stepped voltage to the insulation defect of the gas-insulated switchgear according to the initial irradiation rate to obtain the first discharge pulse signal of the insulation defect of the gas-insulated switchgear are repeated until the average delay of the first discharge pulse signal is less than or equal to the average delay threshold, and the delay fluctuation coefficient of the first discharge pulse signal is less than or equal to the preset percentage. The initial irradiation rate is then used as the target irradiation rate. The preset irradiation rate is determined based on the target irradiation rate.

2. The method for detecting insulation defects in gas-insulated switchgear according to claim 1, characterized in that, The determination of the comprehensive detection result of the insulation defect of the gas-insulated switchgear based on the discharge activity index includes: If the discharge activity index is less than the first threshold, the comprehensive test result is determined to be good insulation. If the discharge activity index is greater than or equal to the first threshold and less than the second threshold, the comprehensive detection result is determined to indicate the presence of a potential defect. If the discharge activity index is greater than or equal to the second threshold, the comprehensive detection result is determined to indicate the presence of a hazardous defect.

3. The method for detecting insulation defects in gas-insulated switchgear according to claim 1, characterized in that, Before applying short-wave irradiation and a stepped voltage to the insulation defects of the gas-insulated switchgear according to the initial irradiation rate to obtain the first discharge pulse signal of the insulation defects of the gas-insulated switchgear, the method further includes: Based on the manufacturing process data or historical testing data of the gas-insulated switchgear, determine the estimated air gap size of the insulation defect of the gas-insulated switchgear; The initial irradiation rate is determined based on the estimated air gap size.

4. The method for detecting insulation defects in gas-insulated switchgear according to claim 1, characterized in that, Determining the preset irradiation rate based on the target irradiation rate includes: According to the target irradiation rate, the insulation defects of the gas-insulated switchgear are subjected to short-wave irradiation and a stepped voltage is applied. The second discharge pulse signal of the insulation defects of the gas-insulated switchgear is continuously acquired until a second discharge pulse signal of a preset number of power frequency cycles is acquired. If the average delay of the second discharge pulse signal for a preset number of power frequency cycles is less than or equal to the average delay threshold, and the delay fluctuation coefficient of the second discharge pulse signal for a preset number of power frequency cycles is less than or equal to the preset percentage, then the target irradiation rate is taken as the preset irradiation rate.

5. The method for detecting insulation defects in gas-insulated switchgear according to claim 1, characterized in that, Before applying short-wave irradiation and a stepped voltage to the insulation defects of the gas-insulated switchgear according to a preset irradiation rate, and obtaining the current discharge pulse signal of the insulation defects of the gas-insulated switchgear, the method further includes: A stepped voltage is applied to the insulation defect of the gas-insulated switchgear to obtain a non-discharge pulse signal of the insulation defect of the gas-insulated switchgear. Before determining the discharge activity index based on the maximum pulse peak value, pulse repetition frequency, and average pulse energy of the current discharge pulse signal, the method further includes: The discharge pulse threshold is determined based on the baseline voltage of the no-discharge pulse signal; The current discharge pulse signal is filtered according to the discharge pulse threshold to obtain the filtered current discharge pulse signal. The filtered current discharge pulse signal is used as the current discharge pulse signal.

6. The method for detecting insulation defects in gas-insulated switchgear according to claim 1, characterized in that, The method further includes: If the pulse density of the current discharge pulse signal is greater than the pulse density threshold, the steps of short-wave irradiating the insulation defect of the gas-insulated switchgear with a preset irradiation rate and applying a stepped voltage to obtain the current discharge pulse signal of the insulation defect of the gas-insulated switchgear are repeated until the pulse density of the current discharge pulse signal is less than or equal to the pulse density threshold.

7. The method for detecting insulation defects in gas-insulated switchgear according to claim 4, characterized in that, The method further includes: If, in the second discharge pulse signal of the preset number of power frequency cycles, the average time delay of the second discharge pulse signal of at least one power frequency cycle is greater than the average time delay threshold, or the time delay fluctuation coefficient of the second discharge pulse signal of at least one power frequency cycle is greater than the preset percentage, then the step of performing shortwave irradiation and applying stepped voltage to the insulation defect of the gas-insulated switchgear according to the initial irradiation rate to obtain the first discharge pulse signal of the insulation defect of the gas-insulated switchgear is returned, until the average time delay of the second discharge pulse signal of the preset number of power frequency cycles is less than or equal to the average time delay threshold, and the time delay fluctuation coefficient of the second discharge pulse signal of the preset number of power frequency cycles is less than or equal to the preset percentage.

8. An insulation defect detection system for gas-insulated switchgear, characterized in that, The system includes a shortwave radiation source, a high-frequency current sensor, and a processor; Both the shortwave radiation source and the high-frequency current sensor are connected to the processor. The shortwave radiation source is used to irradiate insulation defects in gas-insulated switchgear with shortwave radiation and apply stepped voltage. The high-frequency current sensor is used to collect discharge pulse signals; The processor is used to execute the insulation defect detection method for gas-insulated switchgear as described in any one of claims 1 to 7; The shortwave radiation source includes an X-ray tube, a copper filter with switchable thickness, a high-voltage power supply, and a coupling capacitor; the high-frequency current sensor includes a partial discharge detector and a high-speed acquisition card.

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