A method and system for monitoring partial discharge of a high-voltage switch cabinet

Abstract

This invention relates to the field of electrical variable measurement technology, specifically to a method and system for monitoring partial discharge in high-voltage switchgear. The method includes: acquiring partial discharge signals and grounding current signals from the high-voltage switchgear to determine the overall discharge threat level; determining a grounding correlation factor; determining a comprehensive discharge intensity index based on the overall discharge threat level and the grounding correlation factor; determining a comprehensive early warning index based on the Z-scores of the comprehensive discharge intensity index sequences within a first predetermined time period, a second predetermined time period, and a third predetermined time period, where the second predetermined time period is longer than the first predetermined time period, and the third predetermined time period is longer than the second predetermined time period; and using the comprehensive early warning index to provide insulation fault early warning for the high-voltage switchgear. Thus, this invention improves the reliability and accuracy of the partial discharge monitoring results for high-voltage switchgear.

Description

Technical Field

[0001] This invention relates to the field of electrical variable measurement technology, specifically to a method and system for monitoring partial discharge in high-voltage switchgear. Background Technology

[0002] High-voltage switchgear in mines is the core power distribution equipment in underground power supply systems. It integrates core components such as busbars, circuit breakers, and instrument transformers, providing stable and reliable power support for various electromechanical equipment used in underground coal mining, ventilation, and drainage. Under long-term harsh operating conditions and the combined effects of electrical, thermal, mechanical, and environmental stresses, the internal insulation materials of high-voltage switchgear gradually age and deteriorate, resulting in various insulation defects such as cracks, air gaps, and surface contamination. When the electric field distorts and becomes highly concentrated at these insulation defects, exceeding the local tolerance limit of the dielectric, it triggers a discharge phenomenon, i.e., partial discharge. Although this discharge does not immediately form a penetrating conductive path and is an early sign of insulation failure, it continuously erodes the insulation material, accelerating the deterioration process. Long-term development can easily lead to insulation breakdown, causing damage to the high-voltage switchgear, interruption of underground power supply, and directly threatening the safety of mine personnel and the continuity of production. Therefore, accurate monitoring and early warning of partial discharge are crucial.

[0003] In some scenarios, the electromagnetic environment inside high-voltage switchgear in mines is complex. Affected by factors such as underground humidity, dust accumulation, and strong electromagnetic interference, traditional partial discharge monitoring methods have significant limitations, making it difficult to accurately capture and reliably assess early signs of insulation faults. On the one hand, the asynchronous acquisition of key monitoring signals such as partial discharge and grounding current leads to a loss of temporal correlation between signals, making it impossible to construct an effective causal analysis chain. This results in a lack of scientific basis for verifying the authenticity of partial discharges, making it difficult to distinguish between real discharges and environmental interference signals, leading to low reliability and accuracy of partial discharge assessment results. On the other hand, traditional monitoring methods heavily rely on fixed judgment rules for the quantitative analysis of discharge characteristics, failing to adapt to individual equipment differences and the slow performance drift during long-term operation, further reducing the reliability and accuracy of partial discharge assessment results. Therefore, the low reliability and accuracy of the aforementioned partial discharge monitoring results for high-voltage switchgear make it difficult to sensitively capture and provide early warning of insulation faults in high-voltage switchgear. Summary of the Invention

[0004] To address the technical problem of low reliability and accuracy of partial discharge monitoring results in high-voltage switchgear, the present invention aims to provide a method for monitoring partial discharge in high-voltage switchgear.

[0005] To solve the above technical problems, the specific technical solution adopted is as follows:

[0006] In a first aspect, embodiments of the present invention provide a method for monitoring partial discharge in high-voltage switchgear, comprising: acquiring partial discharge signals and grounding current signals of the high-voltage switchgear, and determining a comprehensive discharge threat level based on the amplitude of the partial discharge signal at each sampling point of the partial discharge signal and the maximum amplitude of each historical partial discharge signal within a predetermined historical window; determining a grounding correlation factor based on the non-power frequency component in the grounding current signal and the partial discharge signal; determining a comprehensive discharge intensity index based on the comprehensive discharge threat level and the grounding correlation factor; determining a comprehensive early warning index based on the discharge intensity index sequence within a first predetermined time period, the discharge intensity index sequence within a second predetermined time period, and the Z-score of the discharge intensity index within a third predetermined time period, wherein the second predetermined time period is longer than the first predetermined time period, the third predetermined time period is longer than the second predetermined time period, and using the comprehensive early warning index to provide an insulation fault early warning for the high-voltage switchgear.

[0007] Optionally, determining the comprehensive discharge threat level based on the partial discharge signal amplitude at each sampling point of the partial discharge signal and the maximum amplitude of each historical partial discharge signal within a predetermined historical window includes: determining the effective value of the partial discharge signal based on the partial discharge signal amplitude at each sampling point of the partial discharge signal; determining the partial discharge signal characteristic factor of the partial discharge signal based on the average value and effective value of the partial discharge signal within the predetermined window; determining the original signal pulse characteristic factor based on the maximum amplitude and effective value of the partial discharge signal within the predetermined window; determining the average relative amplitude based on the partial discharge signal amplitude at each sampling point of the partial discharge signal and the maximum amplitude of each historical partial discharge signal within the predetermined historical window; determining the partial discharge intensity factor based on the partial discharge signal characteristic factor and the average relative amplitude within the predetermined window; determining the hazard amplification factor based on the partial discharge intensity factor within each predetermined window; and determining the comprehensive discharge threat level based on the partial discharge signal characteristic factor and the hazard amplification factor.

[0008] Optionally, determining the partial discharge intensity factor based on the partial discharge signal characteristic factor and the average relative amplitude within a predetermined window includes: calculating a first difference between a predetermined value and the average relative amplitude; and determining the partial discharge intensity factor based on the first difference and the partial discharge signal characteristic factor.

[0009] Optionally, determining the grounding correlation factor based on the non-power frequency component and partial discharge signal in the grounding current signal includes: extracting the power frequency component of the grounding current at a predetermined frequency from the grounding current signal; determining the non-power frequency component based on the grounding current signal and the power frequency component at the predetermined frequency; determining the cross-correlation coefficient between the partial discharge signal and the non-power frequency component delayed within the time delay interval; determining the time delay corresponding to the maximum value of the cross-correlation coefficient as the cross-correlation peak value; determining the non-power frequency energy of the grounding current based on the non-power frequency component within a predetermined window; and determining the grounding correlation factor based on the non-power frequency energy and the cross-correlation peak value.

[0010] Optionally, determining the grounding correlation factor based on non-power frequency energy and cross-correlation peak value includes: determining the average value of the non-power frequency energy of the grounding current for multiple consecutive historical windows; calculating the ratio between the non-power frequency energy of the grounding current in the current predetermined window and the average value; and determining the grounding correlation factor based on the ratio and cross-correlation peak value.

[0011] Optionally, the comprehensive discharge intensity index is determined based on the overall discharge threat level and the grounding correlation factor by: calculating the sum between the predetermined value and the grounding correlation factor; and determining the comprehensive discharge intensity index based on the sum and the overall discharge threat level.

[0012] Optionally, the comprehensive early warning index is determined based on the discharge intensity comprehensive index sequence within a first predetermined time period, the discharge intensity comprehensive index sequence within a second predetermined time period, and the Z-score of the discharge intensity comprehensive index within a third predetermined time period. This includes: determining a first rate of change of the discharge intensity comprehensive index based on the discharge intensity comprehensive index sequence within the first predetermined time period; determining a second rate of change of the discharge intensity comprehensive index based on the discharge intensity comprehensive index sequence within the second predetermined time period; determining the comprehensive deterioration degree of the insulation material of the high-voltage switchgear using the first and second rates of change; determining the insulation material condition risk index based on the Z-score of the discharge intensity comprehensive index within the third predetermined time period; and determining the comprehensive early warning index based on the insulation material condition risk index and the comprehensive deterioration degree of the insulation material.

[0013] Optionally, determining the overall deterioration degree of the insulation material of the high-voltage switchgear using the first rate of change and the second rate of change includes: calculating a second difference between the second rate of change and the first rate of change; determining a first weight of the first rate of change and a second weight of the second rate of change based on the second difference; and determining the overall deterioration degree of the insulation material of the high-voltage switchgear based on the first weight, the second weight, the first rate of change, and the second rate of change.

[0014] Optionally, determining the insulation material condition risk index based on the Z-score of the comprehensive discharge intensity index within the third predetermined time period includes: determining the insulation material condition risk index based on the larger value between a preset value and the Z-score of the comprehensive discharge intensity index within the third predetermined time period.

[0015] In a second aspect, embodiments of the present invention provide a partial discharge monitoring system for high-voltage switchgear, comprising: a processor and a memory; wherein the memory is used to store a computer program that can run on the processor; the processor is used to execute the program stored in the memory to implement the steps of the partial discharge monitoring method for high-voltage switchgear mentioned in the first aspect.

[0016] The present invention has the following beneficial effects: In this embodiment, the partial discharge signal and grounding current signal of the high-voltage switchgear are acquired simultaneously, preserving the temporal correlation between the signals. This distinguishes between actual partial discharge and environmental electromagnetic interference, solving the problem of missing authenticity verification caused by the asynchronous nature of traditional signals and significantly improving the reliability of the monitoring signals. Furthermore, this embodiment calculates the comprehensive discharge threat level based on the amplitude of the partial discharge signal and historical extreme values. It also combines the non-power frequency component of the grounding current with the partial discharge signal to obtain a grounding correlation factor, thereby forming a comprehensive discharge intensity index. This achieves a multi-dimensional and quantitative characterization of partial discharge, breaking away from the traditional evaluation mode that relies solely on a single signal or fixed threshold, and significantly improving the reliability and accuracy of partial discharge intensity assessment. Furthermore, this embodiment uses a multi-time-period discharge intensity sequence combined with Z-scores to construct a comprehensive early warning index. This index can adapt to individual differences in different switchgear equipment, as well as changes such as slow decay of insulation performance and drift in monitoring characteristics during long-term operation. It does not rely on fixed judgment rules, solving the problems of adapting to individual equipment differences and slow performance drift during long-term operation. Therefore, the embodiments of the present invention use multi-scale, adaptive comprehensive early warning indicators as the basis for fault early warning, which can accurately capture early weak signs of insulation faults, realize early fault warning, improve the reliability and accuracy of the results of partial discharge monitoring of high-voltage switchgear, and can sensitively capture and provide early warning of insulation faults in high-voltage switchgear. Attached Figure Description

[0017] To more clearly illustrate the technical solutions and advantages 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.

[0018] Figure 1 A flowchart illustrating a partial discharge monitoring method for high-voltage switchgear according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of a partial discharge monitoring system for a high-voltage switchgear, provided as an embodiment of the present invention. Detailed Implementation

[0020] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a partial discharge monitoring method and system for high-voltage switchgear proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0021] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] The specific scheme of the partial discharge monitoring method for high-voltage switchgear provided by the present invention will be described in detail below with reference to the accompanying drawings. Example 1

[0024] Please see Figure 1 The flowchart illustrates a partial discharge monitoring method for high-voltage switchgear provided in an embodiment of the present invention, including:

[0025] Step S101: Obtain the partial discharge signal and grounding current signal of the high-voltage switchgear, and determine the comprehensive discharge threat level based on the partial discharge signal amplitude at each sampling point of the partial discharge signal and the maximum amplitude of each historical partial discharge signal within the predetermined historical window.

[0026] Specifically, as the core equipment of a mine power supply system, the high-voltage switchgear in a mine has an extremely complex internal electromagnetic environment. Affected by the harsh working conditions of underground mines, such as humidity, dust, and electromagnetic interference, insulation faults such as partial discharge and abnormal grounding can easily occur inside the switchgear, leading to serious accidents such as equipment damage and power outages. This invention, considering the limited installation space, strong environmental interference, and high maintenance difficulty of mine switchgear underground, selects sensors and acquisition modules that are highly anti-interference, easy to install, and adapted to underground working conditions. The specific process is as follows:

[0027] First, a bandwidth-adaptive high-frequency current sensor, resistant to dust and electromagnetic interference, is selected and connected in series inside the mine switchgear to key locations prone to partial discharge, such as cable joints and busbars, to collect partial discharge signals. The sampling rate of the acquisition module is set to 10MHz.

[0028] Secondly, a Rogowski coil grounding current sensor with a range adapted to the grounding current range of the mine switchgear and strong anti-interference capability is selected and installed at an easily monitored location on the grounding wire of the switchgear to collect the grounding current signal. The sampling rate of the acquisition module is set to 200kHz.

[0029] Finally, considering the large voltage fluctuations in the mine power grid, a power frequency voltage zero-crossing triggering method is adopted. The power frequency voltage signal on the incoming side of the high-voltage switchgear is collected by a voltage sensor. After filtering the electromagnetic interference in the mine by the signal conditioning circuit, the voltage zero-crossing point is accurately detected and a synchronous trigger signal is generated. This synchronous trigger signal is transmitted synchronously to the partial discharge and grounding current acquisition modules to ensure that all modules start acquisition at the same time and achieve strict alignment of various signals on the time axis. The complete acquisition process is set to be executed once every 5 minutes, and each acquisition includes two types of signals: partial discharge and grounding current.

[0030] Furthermore, the raw partial discharge signals obtained from simultaneous multi-source data acquisition contain a large amount of redundant information, noise interference, and irrelevant frequency components. Directly using these signals for insulation condition assessment can lead to biased results and fail to accurately reflect the specific characteristics of insulation faults. Simultaneously, the raw partial discharge signals themselves lack clear physical meaning and are difficult to directly correlate with the degradation patterns of the insulation condition. Analysis shows that partial discharge signals caused by insulation degradation generate high-frequency pulse currents. The larger the amplitude of the discharge pulse, the more severe the insulation defect and the higher the risk of breakdown. Therefore, it is necessary to measure the overall energy level of the discharge pulse. Among these, partial discharge intensity is a core indicator reflecting the magnitude and activity of discharge energy within the insulation. By selecting two independent parameters—the effective value of the partial discharge signal and the partial discharge pulse count—the characteristics of partial discharge intensity can be comprehensively characterized.

[0031] Furthermore, as an optional embodiment of the present invention, determining the comprehensive discharge threat level based on the partial discharge signal amplitude at each sampling point of the partial discharge signal and the maximum amplitude of each historical partial discharge signal within a predetermined historical window includes: determining the effective value of the partial discharge signal based on the partial discharge signal amplitude at each sampling point of the partial discharge signal; determining the partial discharge signal characteristic factor of the partial discharge signal based on the average value and effective value of the partial discharge signal within the predetermined window; determining the original signal pulse characteristic factor based on the maximum amplitude and effective value of the partial discharge signal within the predetermined window; determining the average relative amplitude based on the partial discharge signal amplitude at each sampling point of the partial discharge signal and the maximum amplitude of each historical partial discharge signal within the predetermined historical window; determining the partial discharge intensity factor based on the partial discharge signal characteristic factor and the average relative amplitude within the predetermined window; determining the hazard amplification factor based on the partial discharge intensity factor within each predetermined window; and determining the comprehensive discharge threat level based on the partial discharge signal characteristic factor and the hazard amplification factor.

[0032] Specifically, in this embodiment of the invention, the amplitude of the partial discharge signal at each sampling point in the partial discharge signal is first squared, then the mean of all squared values ​​is obtained, and finally the square root of the mean of all squared values ​​is taken to obtain the effective value of the partial discharge signal. The unit is mV. Then, the average amplitude of the partial discharge signal at each sampling point within a predetermined window of N=200ms for the high-voltage switchgear is calculated to obtain the aforementioned effective value. The ratio between the partial discharge signal and the average value, thus eliminating the dimension, yields the characteristic factor of the partial discharge signal. .

[0033] Furthermore, analysis shows that because real partial discharge signals are characterized by being "brief, sudden, and concentrated in energy," the more significant and concentrated the pulses in the partial discharge signal, the greater the likelihood of partial discharge and the more severe the insulation defect. Therefore, this embodiment of the invention directly calculates the maximum amplitude and effective value of the partial discharge signal within a predetermined window of size N. The ratio between them yields the dimensionless original signal pulse characteristic factor. The original signal pulse characteristic factor The larger the value, the stronger the partial discharge pulse.

[0034] Furthermore, in this embodiment of the invention, the amplitude of the partial discharge signal at each sampling point in the partial discharge signal and the maximum amplitude of each historical partial discharge signal within a predetermined historical window are obtained. The ratio of the absolute value of the amplitude of the partial discharge signal at each sampling point in the partial discharge signal to the absolute value of the maximum amplitude of each historical partial discharge signal within each predetermined historical window is calculated. The ratios corresponding to all sampling points within each predetermined historical window are summed and the mean value is obtained to obtain the average relative amplitude. The value ranges from [0,1]. The smaller the value, the more concentrated the energy is at a few points, and the stronger the pulse. The size of the historical predetermined window can also be N=200ms. To prevent the denominator from being 0, 0.001 can be added to the "absolute value of the maximum amplitude of each historical partial discharge signal within each historical predetermined window" in the denominator, thus ensuring that the calculation is meaningful.

[0035] Furthermore, the larger the peak factor and the smaller the average relative amplitude, the stronger the pulse characteristics of the signal and the higher the probability of partial discharge. Therefore, as an optional embodiment of the present invention, determining the partial discharge intensity factor based on the partial discharge signal characteristic factor and the average relative amplitude within a predetermined window includes: calculating a first difference between a predetermined value and the average relative amplitude; and determining the partial discharge intensity factor based on the first difference and the partial discharge signal characteristic factor.

[0036] Specifically, in this embodiment of the invention, the predetermined value can be 1. This embodiment of the invention uses the following formula to calculate the partial discharge intensity factor:

[0037]

[0038] In the above formula, This represents the partial discharge intensity factor. This represents the characteristic factor of the original signal pulse. This represents the average relative amplitude.

[0039] Furthermore, embodiments of the present invention calculate the partial discharge intensity factor within each predetermined window. The average value is then used to calculate the partial discharge intensity factor for the current predetermined window. With each partial discharge intensity factor within each predetermined window The ratio between the average values ​​is used to obtain the hazard amplification factor. To prevent the denominator from being zero, a "partial discharge intensity factor" can be added to the denominator. Add 0.001 to the "average value" field to ensure the calculation is meaningful.

[0040] Furthermore, embodiments of the present invention obtain a hazard amplification factor. With partial discharge signal characteristic factors The product between them, and the amplification factor for the hazard. With partial discharge signal characteristic factors The product between them is normalized using the norm function to obtain the overall discharge threat level. The larger the value, the greater the discharge level and the higher the probability of a fault in the short term.

[0041] Step S102: Determine the grounding correlation factor based on the non-power frequency component and partial discharge signal in the grounding current signal.

[0042] Specifically, based on prior knowledge, when partial discharge occurs inside a mine switchgear, the discharge current will form a loop through the grounding wire, resulting in non-power frequency components related to partial discharge appearing in the grounding current. According to analysis, the actual partial discharge current will be coupled to the grounding system through distributed capacitance. The closer the discharge point is to the grounding part, or the larger the discharge current, the more high-frequency components similar to the partial discharge signal will appear in the grounding current, and the time relationship between the two is fixed.

[0043] Therefore, as an optional embodiment of the present invention, determining the grounding correlation factor based on the non-power frequency component and the partial discharge signal in the grounding current signal includes: extracting the power frequency component of the grounding current at a predetermined frequency from the grounding current signal; determining the non-power frequency component based on the grounding current signal and the power frequency component at the predetermined frequency; determining the cross-correlation coefficient between the partial discharge signal and the non-power frequency component delayed within the time delay interval; determining the time delay corresponding to the maximum value of the cross-correlation coefficient as the cross-correlation peak value; determining the non-power frequency energy of the grounding current based on the non-power frequency component within a predetermined window; and determining the grounding correlation factor based on the non-power frequency energy and the cross-correlation peak value.

[0044] Specifically, in this embodiment of the invention, the predetermined frequency can be 50Hz. This embodiment of the invention first uses a grounding current signal... Extracting the 50Hz power frequency component from the grounding current The 50Hz power frequency component This is mainly generated by the normal operation of the mine's power grid and is unrelated to partial discharge. Then, the grounding current signal is acquired. With 50Hz power frequency component The difference between them yields the non-power frequency component. This non-power frequency component It includes the discharge current generated by partial discharge and a small amount of non-power frequency interference current in the mine.

[0045] Furthermore, embodiments of the present invention define a time delay interval. Step size is This range and step size are set based on empirical values, representing the maximum propagation delay of electromagnetic waves within the switchgear. This is due to partial discharge signals. With ground current signal Different sampling rates, therefore for The envelope is extracted using Hilbert transform, and the envelope signal is downsampled to reduce its frequency to that of the ground signal. Same, therefore with Timeline alignment.

[0046] Furthermore, this embodiment of the invention obtains partial discharge signals based on existing cross-correlation coefficient calculation methods. With delay Non-power frequency component of the subsequent grounding current signal The cross-correlation coefficient is calculated using the following formula:

[0047]

[0048] In the above formula, Indicates partial discharge signal With delay Non-power frequency component of the subsequent grounding current signal The cross-correlation coefficient. This represents the peak value of the partial discharge signal at the i-th sampling point. This indicates the delay of the ground current signal at the i-th sampling point. The signal peak value after that. ) represents the peak value of the ground current signal at the i-th sampling point. This is to prevent the denominator from being 0, thus ensuring that the calculation formula is meaningful.

[0049] Furthermore, traverse the aforementioned time delay intervals. The optimal time delay is determined by obtaining the time delay corresponding to the maximum value of the cross-correlation coefficient, which aligns the two signals. This yields the peak cross-correlation value. The peak value of the cross-correlation The larger the value, the stronger the correlation, indicating that it is very likely the same discharge event, with the discharge directly coupled to the grounding system.

[0050] Following this, analysis reveals that because the high-frequency energy injected into the grounding system by partial discharge is converted into heat, accelerating insulation degradation, the stronger the discharge or the closer the discharge point is to the grounding system, the greater the high-frequency energy in the grounding current signal. Therefore, for the non-power frequency components within the entire predetermined window N... Based on the prior current-power calculation formula, the non-power frequency energy of the grounding current is obtained. The unit is Among them, for non-power frequency components Energy integration is performed within a complete predetermined window N to obtain the non-power frequency energy. .

[0051] Furthermore, a genuine discharge threat requires the simultaneous fulfillment of two conditions: strong signal correlation and significant grounding impact. The higher the cross-correlation peak and the greater the grounding energy, the more genuine the discharge and the more severe its impact on the system. Therefore, as an optional embodiment of the present invention, determining the grounding correlation factor based on non-power frequency energy and cross-correlation peak includes: determining the average value of the non-power frequency energy of the grounding current over multiple consecutive historical windows; calculating the ratio between the non-power frequency energy of the grounding current in the current predetermined window and the average value; and determining the grounding correlation factor based on the ratio and the cross-correlation peak.

[0052] Specifically, in this embodiment of the invention, after the equipment is newly commissioned or overhauled and is running stably, 100 sets of data (i.e., 100 consecutive historical windows of N=200ms) are continuously collected, and the non-power frequency energy of the grounding current signal of the 100 sets of data is calculated. The average value is recalculated every six months. Then, the non-power frequency energy of the grounding current within the current predetermined window is calculated again, along with the non-power frequency energy of the grounding current signal from 100 sets of data. The ratio between the average values ​​is used to eliminate the dimensions. Finally, this ratio is obtained along with the cross-correlation peak value. The product of these factors, normalized by the norm function, yields the grounding correlation factor. It should be noted that the grounding current energy noise floor threshold is set to... ,like Directly ordered .

[0053] Step S103: Determine the comprehensive discharge intensity index based on the overall discharge threat level and grounding correlation factor.

[0054] Specifically, the greater the discharge energy and the stronger the grounding correlation, the greater the overall discharge intensity and the greater the threat to insulation. Therefore, as an optional embodiment of the present invention, determining the comprehensive discharge intensity index based on the comprehensive discharge threat level and the grounding correlation factor includes: calculating the sum between a predetermined value and the grounding correlation factor; and determining the comprehensive discharge intensity index based on the sum and the comprehensive discharge threat level.

[0055] The predetermined value can be 1. This embodiment of the invention takes into account even weak grounding correlation ( Even when close to zero, the discharge energy may still pose a threat, so [the following is adopted:] Meanwhile, based on the comprehensive discharge threat level obtained from the above embodiments... To obtain the overall level of discharge threat Grounding correlation factor The product of these two factors yields the comprehensive discharge intensity index. .

[0056] Step S104: Based on the discharge intensity comprehensive index sequence within the first predetermined time period, the discharge intensity comprehensive index sequence within the second predetermined time period, and the Z score of the discharge intensity comprehensive index within the third predetermined time period, a comprehensive early warning index is determined. The second predetermined time period is longer than the first predetermined time period, and the third predetermined time period is longer than the second predetermined time period. The comprehensive early warning index is then used to provide early warning of insulation faults for the high-voltage switchgear.

[0057] Specifically, within actual mines, insulation degradation is a cumulative process over time. Slow, continuous deterioration is more threatening than occasional, instantaneous high values. Furthermore, mine maintenance and scheduling require time, necessitating sufficient advance warning to plan power outage windows. Therefore, it is necessary to consider not only short-term partial discharge situations but also long-term degradation risks. Analysis shows that in the short term, the increase in discharge intensity due to insulation degradation is approximately linear; the faster the discharge intensity increases in the near term, the more rapidly the insulation defects are developing, and the shorter the remaining safe time.

[0058] Therefore, as an optional embodiment of the present invention, determining the comprehensive early warning index based on the discharge intensity comprehensive index sequence within a first predetermined time period, the discharge intensity comprehensive index sequence within a second predetermined time period, and the Z-score of the discharge intensity comprehensive index within a third predetermined time period includes: determining a first rate of change of the discharge intensity comprehensive index based on the discharge intensity comprehensive index sequence within the first predetermined time period; determining a second rate of change of the discharge intensity comprehensive index based on the discharge intensity comprehensive index sequence within the second predetermined time period; determining the comprehensive deterioration degree of the insulation material of the high-voltage switchgear using the first and second rates of change; determining the insulation material condition risk index based on the Z-score of the discharge intensity comprehensive index within the third predetermined time period; and determining the comprehensive early warning index based on the insulation material condition risk index and the comprehensive deterioration degree of the insulation material.

[0059] Specifically, in this embodiment of the invention, the first predetermined time period can be the most recent 6 hours, the second predetermined time period can be the most recent 30 days, and the third predetermined time period can be the period since the last overhaul or maintenance. Therefore, this embodiment of the invention uses the discharge intensity comprehensive index Is sequence of the most recent 6 hours; the least squares method is used for linear fitting to obtain the first rate of change of the discharge intensity comprehensive index Is sequence. Similarly, the degradation process of insulating materials is usually lengthy and can be approximated as a linear degradation process. Therefore, in this embodiment of the invention, the discharge intensity comprehensive index Is sequence of the most recent 30 days is taken; the least squares method is used for linear fitting to obtain the second rate of change of the discharge intensity comprehensive index Is sequence. .

[0060] Furthermore, analysis shows that when the short-term rate of change in the material degradation process is greater than the long-term rate of change, it indicates that the insulation material of the switchgear is affected by various factors in the short term, and its degradation process is accelerated. Therefore, the short-term rate of change has a larger reference weight. Conversely, when the short-term rate of change in the material degradation process is less than the long-term rate of change, the short-term rate of change should have a smaller reference weight, while the long-term rate of change should have a larger reference weight. Therefore, as an optional embodiment of the present invention, determining the overall deterioration degree of the insulation material of the high-voltage switchgear using the first rate of change and the second rate of change includes: calculating a second difference between the second rate of change and the first rate of change; determining a first weight for the first rate of change and a second weight for the second rate of change based on the second difference; and determining the overall deterioration degree of the insulation material of the high-voltage switchgear based on the first weight, the second weight, the first rate of change, and the second rate of change.

[0061] Specifically, the embodiments of the present invention obtain the second rate of change. (Subtraction) and the first rate of change The difference between (minuends) is denoted as At this time, when this value When the value is greater than 0, the reference weight of the first rate of change is higher; conversely, it is lower. In special cases, if the difference between the two is 0, then the second rate of change should be assigned. With the first rate of change Same reference weights.

[0062] Furthermore, this embodiment of the invention therefore employs the Sigmoid function to obtain the first rate of change. Reference weight For this value, when When, the Sigmoid function value Short-term weights An increase occurs; conversely, a decrease occurs. This corresponds to the second rate of change. The reference weight should be This weight satisfies the condition that... At that time, both had a weight of 0.5.

[0063] Therefore, the following formula is used to obtain the overall deterioration degree of the insulation material of the high-voltage switchgear;

[0064]

[0065] In the above formula, This indicates the overall deterioration of the insulation materials in high-voltage switchgear. This represents the normalization function. This represents the first rate of change. This represents the second rate of change. express Reference weights. express Reference weights.

[0066] It should be noted that at this time, when this value A value greater than 0, and the higher the value, the more rapidly the insulation condition is deteriorating. Furthermore, the insulation material will not function properly without any maintenance. The situation.

[0067] Furthermore, in actual mine operations, maintenance personnel face information overload from multi-dimensional monitoring parameters, while the continuity of production scheduling demands precise and timely maintenance decisions. Analysis shows that when the comprehensive discharge intensity index... The higher the value, the more severe the current insulation defect, and the greater the base probability of breakdown; the higher the overall deterioration level of the insulation material... The higher the value, the faster the insulation condition is deteriorating, the faster the risk of failure is increasing, and the shorter the remaining safe operating time. Therefore, as an optional embodiment of the present invention, determining the insulation material condition risk index based on the Z-score of the comprehensive discharge intensity index within a third predetermined time period includes: determining the insulation material condition risk index based on the larger value between a preset value and the Z-score of the comprehensive discharge intensity index within the third predetermined time period.

[0068] Specifically, the preset value in this embodiment of the invention can be 0. This embodiment of the invention is based on the Z-score algorithm, which calculates the comprehensive discharge intensity index for all times since the last overhaul or maintenance. The Z-score is denoted as At the same time, a base value of 1 is set based on the equipment's historical normal state as the statistical benchmark; at this time, if the current comprehensive discharge intensity index... If the value does not exceed the historical average, the baseline value of 1 is taken. Therefore, the condition risk index of the insulation material is calculated using the following formula:

[0069]

[0070] In the above formula, This indicates the risk index of the insulation material's condition. Indicator of comprehensive discharge intensity The Z-score. This represents the maximum value function.

[0071] Furthermore, embodiments of the present invention obtain an insulation material condition risk index. The comprehensive early warning index is obtained by multiplying the comprehensive deterioration degree T of the insulation material and normalizing it using a norm function; the larger the comprehensive early warning index value, the higher the risk and the stronger the urgency to take maintenance actions.

[0072] Furthermore, this embodiment of the invention sets a threshold of 0.5 based on experience. When the comprehensive early warning index is greater than or equal to the threshold of 0.5, an insulation risk is considered to exist. A special inspection plan is formulated, and emergency plans are prepared, including backup power supply switching schemes and fault isolation plans. The triggering, modification, cancellation, and all response measures for any early warning level must be fully recorded in the system to form a traceable electronic work order. A monthly early warning statistical analysis report is generated, which includes the number of early warnings for each cabinet, duration, cause, handling effect, and improvement suggestions.

[0073] It is worth noting that all the norm functions described above in this embodiment of the invention are normalized using Min-Max.

[0074] This invention simultaneously acquires partial discharge signals and grounding current signals from high-voltage switchgear, preserving the temporal correlation between the signals. This distinguishes between actual partial discharge and environmental electromagnetic interference, solving the problem of missing authenticity verification caused by asynchronous signals in traditional methods and significantly improving the reliability of monitoring signals. Furthermore, this invention calculates the comprehensive discharge threat level based on the amplitude of the partial discharge signal and historical extreme values. It also combines the non-power frequency component of the grounding current with the partial discharge signal to obtain a grounding correlation factor, thereby forming a comprehensive discharge intensity index. This achieves a multi-dimensional and quantitative characterization of partial discharge, moving away from the traditional evaluation model that relies solely on a single signal or fixed threshold, significantly improving the reliability and accuracy of partial discharge intensity assessment. Furthermore, this invention uses a multi-time-segment discharge intensity sequence combined with Z-scores to construct a comprehensive early warning index. This index can adapt to individual differences in different switchgear equipment, as well as changes such as slow decay of insulation performance and drift in monitoring characteristics during long-term operation. It does not rely on fixed judgment rules, solving the problems of adapting to individual equipment differences and slow performance drift during long-term operation. Therefore, the embodiments of the present invention use multi-scale, adaptive comprehensive early warning indicators as the basis for fault early warning, which can accurately capture early weak signs of insulation faults, realize early fault warning, improve the reliability and accuracy of the results of partial discharge monitoring of high-voltage switchgear, and can sensitively capture and provide early warning of insulation faults in high-voltage switchgear.

[0075] Furthermore, this embodiment of the invention calculates the comprehensive discharge threat level, integrating discharge energy and pulse characteristics to more comprehensively characterize the level of discharge activity; it introduces a grounding correlation factor, verifies the authenticity of the discharge and quantifies its impact on the grounding system through cross-correlation analysis, significantly improving the accuracy and reliability of fault identification; furthermore, by dynamically weighting and integrating short-term and long-term degradation trends, it achieves sensitive capture and early warning of the accelerated deterioration process of insulation condition; the final comprehensive early warning index organically integrates the current discharge intensity and condition deterioration rate, providing maintenance personnel with intuitive and quantitative decision-making basis, thereby enabling a shift from passive maintenance to proactive predictive maintenance, rationally scheduling power outage maintenance windows, effectively preventing serious accidents, and ensuring the safe and continuous operation of the mine power supply system. Example 2

[0076] Corresponding to the high-voltage switchgear partial discharge monitoring method provided in the above embodiments, based on the same technical concept, this embodiment of the invention also provides a high-voltage switchgear partial discharge monitoring system, which is used to execute the above-described high-voltage switchgear partial discharge monitoring method. Figure 2 This is a schematic diagram of the structure of a partial discharge monitoring system for a high-voltage switchgear according to an embodiment of the present invention, as shown below. Figure 2As shown. Partial discharge monitoring systems for high-voltage switchgear can vary significantly due to differences in configuration or performance. They may include one or more processors 201 and memory 202. The memory 202 stores computer programs that can run on the processor 201. The processor 201 executes the programs stored in the memory 202 to achieve the above... Figure 1 The various steps in the Chinese method embodiment. The memory 202 can be temporary or persistent storage. The application program stored in the memory 202 may include one or more modules (not shown in the figures), each module may include a series of computer-executable instructions for the partial discharge monitoring system of the high-voltage switchgear.

[0077] Furthermore, the processor 201 can be configured to communicate with the memory 202 and execute a series of computer-executable instructions stored in the memory 202 on the high-voltage switchgear partial discharge monitoring system. The high-voltage switchgear partial discharge monitoring system may also include one or more power supplies 203, one or more wired or wireless network interfaces 204, one or more input / output interfaces 205, and one or more keyboards 206.

[0078] Specifically, in this embodiment, the high-voltage switchgear partial discharge monitoring system includes a processor, a communication interface, a memory, and a communication bus; wherein, the processor, communication interface, and memory communicate with each other via the bus; the memory stores computer programs; and the processor executes the programs stored in the memory to achieve the above... Figure 1 The various steps in the method embodiments are the same as those in the above method embodiments, and have the same beneficial effects. To avoid repetition, the embodiments of the present invention will not be described again here.

[0079] It should be noted that the high-voltage switchgear partial discharge monitoring system and the high-voltage switchgear partial discharge monitoring method provided in this embodiment are based on the same application concept. Therefore, the specific implementation of this embodiment can refer to the implementation of the aforementioned high-voltage switchgear partial discharge monitoring method, and has the same or similar beneficial effects. Repeated parts will not be described again.

[0080] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0081] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0082] This invention also proposes a computer-readable storage medium storing one or more programs, which, when executed by a high-voltage switchgear partial discharge monitoring system including multiple application programs, cause the high-voltage switchgear partial discharge monitoring system to perform... Figure 1 The methods disclosed in the embodiments shown achieve the functions and beneficial effects of the methods in the preceding method embodiments, and will not be repeated here.

[0083] The computer-readable storage media include read-only memory (ROM), random access memory (RAM), magnetic disks or optical disks, etc.

Claims

1. A partial discharge monitoring method for a high voltage switchgear, characterized in that, include: Acquire partial discharge signals and grounding current signals from the high-voltage switchgear, and determine the overall discharge threat level based on the partial discharge signal amplitude at each sampling point of the partial discharge signal and the maximum amplitude of each historical partial discharge signal within a predetermined historical window. The grounding correlation factor is determined based on the non-power frequency component and partial discharge signal in the grounding current signal; Based on the comprehensive discharge threat level and the grounding correlation factor, a comprehensive discharge intensity index is determined; A comprehensive early warning index is determined based on the discharge intensity comprehensive index sequence within a first predetermined time period, the discharge intensity comprehensive index sequence within a second predetermined time period, and the Z score of the discharge intensity comprehensive index within a third predetermined time period. The second predetermined time period is longer than the first predetermined time period, and the third predetermined time period is longer than the second predetermined time period. The comprehensive early warning index is then used to provide early warning of insulation faults for the high-voltage switchgear. The determination of the overall discharge threat level includes: The effective value of the partial discharge signal is determined based on the amplitude of the partial discharge signal at each sampling point of the partial discharge signal. Based on the average value and the effective value of the partial discharge signal within a predetermined window, the partial discharge signal characteristic factor of the partial discharge signal is determined, including: calculating the average value of the partial discharge signal amplitude at each sampling point of the partial discharge signal within the predetermined window of the high-voltage switchgear, and using the ratio between the effective value and the average value as the partial discharge signal characteristic factor; Determining the original signal pulse characteristic factor based on the maximum amplitude and the effective value of the partial discharge signal within the predetermined window includes: using the ratio between the maximum amplitude and the effective value of the partial discharge signal within the predetermined window as the original signal pulse characteristic factor. The average relative amplitude is determined based on the partial discharge signal amplitude at each sampling point in the partial discharge signal and the maximum amplitude of each historical partial discharge signal within a predetermined historical window. Determining the partial discharge intensity factor based on the original signal pulse characteristic factor and the average relative amplitude within a predetermined window includes: calculating a first difference between a predetermined value and the average relative amplitude; and multiplying the first difference by the original signal pulse characteristic factor as the partial discharge intensity factor. The hazard amplification factor is determined based on the partial discharge intensity factors within each predetermined window, including: using the ratio between the partial discharge intensity factor of the current predetermined window and the average value of the partial discharge intensity factors within each predetermined window as the hazard amplification factor. Determining the overall discharge threat level based on the partial discharge signal characteristic factor and the hazard amplification coefficient includes: normalizing the product between the hazard amplification coefficient and the partial discharge signal characteristic factor to obtain the overall discharge threat level. The step of determining the grounding correlation factor based on the non-power frequency component and partial discharge signal in the grounding current signal includes: Extract the power frequency component of the grounding current at a predetermined frequency from the grounding current signal; The non-power frequency component is determined based on the grounding current signal and the power frequency component of the predetermined frequency. Determine the cross-correlation coefficient between the partial discharge signal and the non-power frequency component delayed within the time delay interval; The time delay corresponding to the maximum value of the cross-correlation coefficient is determined as the peak value of the cross-correlation. The non-power frequency energy of the grounding current is determined based on the non-power frequency component within the predetermined window. Based on the non-power frequency energy and the cross-correlation peak value, the grounding correlation factor is determined; The determination of the comprehensive discharge intensity index based on the comprehensive discharge threat level and the grounding correlation factor includes: Calculate the sum between the predetermined value and the grounding correlation factor; Based on the sum and the comprehensive discharge threat level, a comprehensive discharge intensity index is determined, including: calculating the sum between a predetermined value and a grounding correlation factor; and using the product of the sum and the comprehensive discharge threat level as the comprehensive discharge intensity index. The comprehensive early warning indicators include: Based on the discharge intensity comprehensive index sequence within the first predetermined time period, determine the first rate of change of the discharge intensity comprehensive index; Based on the discharge intensity comprehensive index sequence within the second predetermined time period, determine the second rate of change of the discharge intensity comprehensive index; The overall deterioration degree of the insulation material of the high-voltage switchgear is determined using the first rate of change and the second rate of change. The state risk index of the insulating material is determined based on the Z score of the comprehensive index of discharge intensity during the third predetermined time period. Based on the insulation material condition risk index and the overall deterioration degree of the insulation material, a comprehensive early warning index is determined, including: using the normalized result of the product of the insulation material condition risk index and the overall deterioration degree of the insulation material as the comprehensive early warning index.

2. The partial discharge monitoring method of a high voltage switchgear according to claim 1, characterized in that, The determination of the grounding correlation factor based on the non-power frequency energy and the cross-correlation peak value includes: Determine the average value of the non-power frequency energy of the grounding current for multiple consecutive historical windows; Calculate the ratio between the non-power frequency energy of the current grounding current in the current predetermined window and the average value; The normalized result of the product between the ratio and the peak value of the cross-correlation is used as the grounding correlation factor.

3. The partial discharge monitoring method of a high voltage switchgear according to claim 1, characterized in that, The determination of the overall deterioration degree of the insulation material of the high-voltage switchgear using the first rate of change and the second rate of change includes: Calculate the second difference between the second rate of change and the first rate of change; The first weight of the first rate of change and the second weight of the second rate of change are determined based on the second difference. Based on the first weight, the second weight, the first rate of change, and the second rate of change, the overall deterioration degree of the insulation material of the high-voltage switchgear is determined. The formula for calculating the overall deterioration degree of the insulation material is as follows: ,in, This indicates the overall deterioration of the insulation materials in the high-voltage switchgear. Represents the normalization function. Indicates the first rate of change. This represents the second rate of change. express Reference weights.

4. The method for monitoring partial discharge in high-voltage switchgear according to claim 1, characterized in that, The determination of the insulation material condition risk index based on the Z-score of the comprehensive discharge intensity index within the third predetermined time period includes: The larger of the preset value and the Z score of the comprehensive index of discharge intensity within the third predetermined time period is used as the state risk index of the insulating material.

5. A partial discharge monitoring system for high-voltage switchgear, characterized in that, include: Processor and memory; wherein the memory is used to store computer programs that can run on the processor; A processor is used to execute a program stored in a memory to implement the steps of the partial discharge monitoring method for high-voltage switchgear as described in any one of claims 1-4.

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