A switch cabinet fault detection method and system

Abstract

The application discloses a kind of switch cabinet fault detection method and system, it is related to switch cabinet technical field, and its technical solution key points include the following steps: the insulation resistance of the switch cabinet to be measured and the interference strength to be measured of the switch cabinet to be measured are collected;The historical detection data of the switch cabinet fault belongs to extraction processing, obtain the attenuation coefficient between insulation resistance and signal transmission loss degree and the disturbance coefficient between electromagnetic interference strength and control instruction distortion degree;According to the interference strength condition influence value, the electromagnetic interference strength to be measured, the disturbance coefficient and the signal transmission attenuation value, the second condition influence value is obtained;After processing and analyzing the first condition influence value, the second condition influence value and the initial detection control performance value of the switch cabinet to be measured, the switch cabinet fault early warning result is output, and the effect is to guarantee the stable operation of power system.

Description

Technical Field

[0001] This invention relates to the field of switchgear technology, and more specifically, to a switchgear fault detection method and system. Background Technology

[0002] As a critical piece of equipment in power transmission and distribution systems, the operational reliability of switchgear directly affects the safety and stability of the power grid. During long-term operation, switchgear is susceptible to factors such as insulation aging, partial discharge, electromagnetic interference, and cabinet vibration, leading to increased signal transmission loss, control command distortion, and abnormal circuit impedance faults. In severe cases, this can result in major safety accidents such as short circuits and tripping. Traditional testing methods often focus on monitoring single parameters, such as judging insulation status solely through insulation resistance or assessing interference levels solely through electromagnetic interference intensity. These methods fail to fully consider the quantitative correlation between insulation degradation and signal transmission loss, nor do they establish a precise mapping relationship between electromagnetic interference and control command distortion. They also easily overlook the coupling effects between different fault causes, resulting in one-sided test results that fail to comprehensively reflect the true operating status of the switchgear. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a switch cabinet fault detection method and system.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for detecting faults in switchgear, the method comprising the following steps: The insulation resistance and electromagnetic interference intensity of the switchgear under test are collected. Historical detection data related to switchgear faults are extracted and processed to obtain the attenuation coefficient between insulation resistance and signal transmission loss, as well as the perturbation coefficient between electromagnetic interference intensity and control command distortion. The signal transmission attenuation value affecting the signal transmission loss in the switch cabinet under test is obtained based on the attenuation coefficient and the insulation resistance to be measured. If the insulation resistance under test does not affect the impedance disturbance of the signal transmission path inside the cabinet, the first condition influence value can be obtained based on the disturbance coefficient, the electromagnetic interference intensity under test, and the signal transmission attenuation value. If the insulation resistance under test causes impedance disturbance to the signal transmission path inside the cabinet, the interference intensity of the part of the switch cabinet under test affected by vibration resonance is determined based on the cabinet vibration resonance amplitude and resonance direction of the part of the switch cabinet under test to which the electromagnetic interference intensity belongs. The second influence value is obtained based on the interference intensity influence value, the electromagnetic interference intensity under test, the perturbation coefficient and the signal transmission attenuation value. After processing and analyzing the impact values ​​of the first condition, the impact values ​​of the second condition, and the initial detection and control performance values ​​of the switchgear under test, the switchgear fault early warning result is output.

[0005] A switchgear fault detection system, comprising: Acquisition module: Acquires the insulation resistance and electromagnetic interference intensity of the switchgear under test; Extraction and processing module: Extracts and processes historical detection data related to switchgear faults to obtain the attenuation coefficient between insulation resistance and signal transmission loss, as well as the perturbation coefficient between electromagnetic interference intensity and control command distortion. First processing module: Obtains the signal transmission attenuation value that affects the signal transmission loss in the switch cabinet under test based on the attenuation coefficient and the insulation resistance to be measured; Second processing module: If the insulation resistance to be measured does not affect the impedance disturbance of the signal transmission path in the cabinet, the first condition influence value is obtained based on the perturbation coefficient, the electromagnetic interference intensity to be measured and the signal transmission attenuation value. The third processing module: If the insulation resistance to be tested causes impedance disturbance to the signal transmission path inside the cabinet, the module determines the interference intensity status of the part of the switch cabinet to be tested affected by vibration resonance based on the cabinet vibration resonance amplitude and resonance direction of the location of the electromagnetic interference intensity to be tested; and obtains the second status influence value based on the interference intensity status influence value, the electromagnetic interference intensity to be tested, the disturbance coefficient and the signal transmission attenuation value. Output module: Processes the first condition influence value, the second condition influence value, and the initial detection and control performance value of the switchgear under test, and outputs the switchgear fault early warning result.

[0006] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves multi-dimensional integrated detection of insulation degradation, electromagnetic interference, and cabinet vibration resonance, breaking through the limitations of traditional single-parameter detection. By quantitatively correlating the impedance and perturbation coefficients, it integrates the effects of insulation degradation on signal transmission loss, electromagnetic interference on control command distortion, and vibration resonance on interference propagation amplification, comprehensively reflecting the switchgear's operating status. By extracting the impedance and perturbation coefficients from historical detection data, it constructs quantitative relationships between insulation resistance and signal transmission loss, and between electromagnetic interference intensity and control command distortion, making the detection results more closely reflect the switchgear's operating patterns and effectively reducing detection deviations caused by differences in operating conditions. Based on whether the insulation resistance under test causes impedance disturbances to the signal transmission path, it calculates the first and second condition impact values ​​respectively. When impedance disturbances exist, it introduces the influence of cabinet vibration resonance amplitude and direction on interference intensity, making the characterization of abnormal states more targeted. It not only outputs fault warning results but also clearly identifies the location and impact range of potential hazards, providing decision-making basis for maintenance personnel, reducing the switchgear failure rate and power outage risk, and ensuring the stable operation of the power system. Attached Figure Description

[0007] Figure 1 This is a flowchart illustrating a switchgear fault detection method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a switchgear fault detection system provided in an embodiment of the present invention. Detailed Implementation

[0008] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0009] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0010] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0011] Reference Figures 1-2 As shown.

[0012] The embodiments further illustrate the switchgear fault detection method and system proposed in this invention.

[0013] A method for detecting faults in switchgear, the method comprising the following steps: The insulation resistance and electromagnetic interference intensity of the switchgear under test are collected. Historical detection data related to switchgear faults are extracted and processed to obtain the attenuation coefficient between insulation resistance and signal transmission loss, as well as the perturbation coefficient between electromagnetic interference intensity and control command distortion. The signal transmission attenuation value affecting the signal transmission loss in the switch cabinet under test is obtained based on the attenuation coefficient and the insulation resistance to be measured. If the insulation resistance under test does not affect the impedance disturbance of the signal transmission path inside the cabinet, the first condition influence value can be obtained based on the disturbance coefficient, the electromagnetic interference intensity under test, and the signal transmission attenuation value. If the insulation resistance under test causes impedance disturbance to the signal transmission path inside the cabinet, the interference intensity of the part of the switch cabinet under test affected by vibration resonance is determined based on the cabinet vibration resonance amplitude and resonance direction of the part of the switch cabinet under test to which the electromagnetic interference intensity belongs. The second influence value is obtained based on the interference intensity influence value, the electromagnetic interference intensity under test, the perturbation coefficient and the signal transmission attenuation value. After processing and analyzing the impact values ​​of the first condition, the impact values ​​of the second condition, and the initial detection and control performance values ​​of the switchgear under test, the switchgear fault early warning result is output.

[0014] The process of collecting the insulation resistance and electromagnetic interference intensity of the switchgear under test includes the following steps: The insulation resistance value is obtained by detecting the insulation resistance of the signal transmission parts inside the switch cabinet under test; Extract the loss resistance threshold that insulation resistance causes signal transmission loss in the switchgear; The insulation resistance value that is less than the loss resistance threshold is determined as the insulation resistance to be measured; The electromagnetic interference intensity under test is obtained by detecting the electromagnetic interference intensity at the location of control command distortion in the switch cabinet under test.

[0015] The testing targets are the critical components inside the switchgear that perform signal transmission functions. The insulation condition of these components directly affects the stability of signal transmission. Examples include busbar connections, relay contact transmission areas, and wiring ports of signal acquisition modules. The testing equipment measures the insulation resistance of these components under operating conditions by applying a standard test voltage. This initial insulation resistance value indicates that the higher the insulation resistance, the stronger the barrier capability of the insulating medium, and the lower the risk of signal loss due to insulation problems during transmission.

[0016] The loss resistance threshold is the criterion for determining whether insulation resistance affects the signal transmission loss of switchgear. For example, for a medium-voltage switchgear with a rated voltage of 10 kV, the loss resistance threshold of its signal transmission part is calibrated according to the material, wire diameter and insulation medium of the signal transmission line. If the insulation medium is cross-linked polyethylene, the loss resistance threshold is set to 100 megohms. The extraction of this threshold needs to rely on the switchgear design technical documents and long-term historical test data to ensure that it can reflect the critical correlation between insulation resistance and signal transmission loss.

[0017] The comparison logic calculates the numerical relationship between the insulation resistance value and the loss resistance threshold. If the insulation resistance value equals the loss resistance threshold, it indicates that the insulation resistance is in a critical state. If the insulation resistance value is greater than the loss resistance threshold, it indicates that the insulation performance is good and will not affect signal transmission loss. In both cases, the insulation resistance value is not included in the test range. Only when the insulation resistance value is less than the loss resistance threshold is the insulation resistance value determined to be the insulation resistance to be tested. When the insulation resistance value is lower than the loss resistance threshold, the insulation performance of the insulating medium deteriorates, forming additional impedance in the signal transmission path, thereby causing signal transmission loss. For example, the insulation resistance value detected at the signal transmission part of a switch cabinet is 80 megohms, while the loss resistance threshold is 100 megohms. Since 80 < 100, the 80 megohms insulation resistance value is determined to be the insulation resistance to be tested.

[0018] The testing focuses on areas within the switchgear where control commands distort. These areas are the core regions where electromagnetic interference (EMI) affects the switchgear's control functions. Examples include the intelligent control unit, the circuit breaker's control loop, and the disconnector's operation command receiving module. These components are responsible for receiving, processing, and executing control commands. Once subjected to EMI, they are highly susceptible to control command distortion, delays, or malfunctions. The testing process utilizes an EMI detector to comprehensively measure the electromagnetic radiation and conducted interference intensity at these distorting control command areas. The detection equipment selects the corresponding detection frequency band based on the electromagnetic characteristics of the area, capturing the actual EMI intensity experienced by that area. This value is the EMI intensity to be measured. For example, if the EMI intensity measured at the switchgear's intelligent control unit is 50 dB / µV, this value is taken as the EMI intensity to be measured.

[0019] The historical detection data related to switchgear faults is extracted and processed to obtain the attenuation coefficient between insulation resistance and signal transmission loss, and the perturbation coefficient between electromagnetic interference intensity and control command distortion. This process includes the following steps: Extract historical abnormal resistance values ​​from the historical detection data of the switchgear faults, where the insulation resistance of the switchgear circuit is less than the loss resistance threshold. The resistance change amplitude is obtained by subtracting the loss resistance threshold and the historical abnormal resistance value. The historical signal transmission loss values ​​of the switchgear corresponding to the resistance change amplitude were extracted from historical detection data. The attenuation coefficient is obtained by comparing the historical signal transmission loss value with the resistance change amplitude. The electromagnetic interference intensity of the risk points of control command distortion in the switchgear is extracted from historical detection data; Historical control command distortion values ​​of the switchgear affected by electromagnetic interference intensity were extracted from historical detection data. The perturbation coefficient is obtained by comparing the historical control command distortion value with the electromagnetic interference intensity.

[0020] Insulation degradation data related to faults is extracted from historical testing data, specifically resistance values ​​where the insulation resistance of the switchgear circuit is lower than the loss resistance threshold during historical testing. Only when the insulation resistance is lower than the loss resistance threshold does it have an actual impact on signal transmission loss; therefore, these resistance values ​​are defined as historical abnormal resistance values. For example, if a switchgear's circuit insulation resistance is 75 megohms in historical testing, while the loss resistance threshold for this switchgear is 100 megohms, since 75 < 100, the 75 megohms value is extracted as a historical abnormal resistance value.

[0021] The amplitude of resistance change = loss resistance threshold - historical abnormal resistance value. The loss resistance threshold is the critical value for insulation performance, and the historical abnormal resistance value is the actual insulation resistance value after degradation. The difference between the two reflects the extent of insulation degradation; the larger the difference, the more severe the insulation degradation. For example, if the loss resistance threshold is 100 megohms and the historical abnormal resistance value is 75 megohms, the calculated resistance change amplitude = 100 - 75 = 25 megohms. This 25 megohm amplitude represents the degree of insulation degradation.

[0022] After obtaining the resistance change amplitude, it is necessary to extract the corresponding historical signal transmission loss value from the historical detection data. The historical signal transmission loss value refers to the actual loss value generated during the signal transmission process of the switchgear under the insulation degradation state corresponding to the resistance change amplitude. This value directly reflects the degree of impact of insulation degradation on signal transmission. For example, when the resistance change amplitude is 25 megohms, the corresponding historical signal transmission loss value is 15%. This 15% loss value represents the proportion of signal transmission loss under this degree of insulation degradation.

[0023] The attenuation coefficient is a quantitative correlation coefficient between changes in insulation resistance and signal transmission loss. The attenuation coefficient = historical signal transmission loss value / resistance change amplitude. By using this ratio, the magnitude of insulation degradation is correlated with the degree of signal transmission loss, yielding the proportion of signal transmission loss corresponding to a unit increase in insulation degradation, thus quantitatively characterizing the impact of insulation degradation on signal transmission. For example, if the historical signal transmission loss value is 15% and the resistance change amplitude is 25 megohms, the calculated attenuation coefficient = 15% / 25 megohms = 0.6% / megohm. This attenuation coefficient represents that every 1 megohm of insulation degradation leads to a 0.6% increase in signal transmission loss.

[0024] The electromagnetic interference (EMI) intensity of areas within the switchgear at risk of control command distortion is extracted from historical monitoring data. These areas are where EMI affects control functions, such as intelligent monitoring and control units and control loops. The extracted EMI intensity represents the interference level experienced by these areas during historical monitoring. For example, the EMI intensity of a certain control command distortion risk area extracted from historical data might be 40 dB / µV.

[0025] The corresponding historical control command distortion values ​​are extracted from historical detection data. The historical control command distortion value refers to the degree of distortion in the switchgear control commands under the influence of a given electromagnetic interference intensity. This value directly reflects the extent of the electromagnetic interference's impact on the control commands. For example, when the electromagnetic interference intensity is 40 dB / µV, the corresponding historical control command distortion value is 8%. An 8% distortion value represents the proportion of control command distortion under this interference intensity.

[0026] The perturbation coefficient is a quantitative correlation coefficient between the intensity of electromagnetic interference (EMI) and the degree of control command distortion. Perturbation coefficient = historical control command distortion value / EMI intensity. By using this ratio, the intensity of EMI is correlated with the degree of control command distortion, yielding the proportion of control command distortion per unit EMI intensity, thus quantitatively characterizing the impact of EMI on control function. For example, if the historical control command distortion value is 8% and the EMI intensity is 40 dB / µV, the calculated perturbation coefficient is 8% / 40 dB / µV = 0.2% / dB / µV. This perturbation coefficient represents that every 1 dB / µV of EMI will lead to a 0.2% increase in control command distortion.

[0027] The signal transmission attenuation value affecting the signal transmission loss inside the switchgear under test is obtained based on the attenuation coefficient and the insulation resistance to be measured. The specific steps include: Distinguish the characteristic components in the attenuation coefficient corresponding to different insulation resistance ranges, and determine the characteristic component that matches the range of the insulation resistance under test as the matching attenuation coefficient. By combining the inherent characteristics of the insulating medium inside the switchgear under test, the actual characterization value of the insulation resistance under test is corrected to obtain the corrected insulation resistance value. The basic resistance value is obtained by performing loss correlation transformation on the modified insulation resistance value based on the adaptive resistance attenuation coefficient. The signal transmission attenuation value is obtained by adjusting the basic attenuation value through loss compensation.

[0028] First, it's necessary to distinguish the characteristic components of the impedance coefficient within different intervals. The impedance coefficient is not a single, constant value, but rather composed of multiple characteristic components corresponding to different insulation resistance intervals. This is because the impact of insulation resistance degradation on signal transmission loss differs across these intervals. For example, the impedance coefficient can be divided into three interval characteristic components, corresponding to insulation resistance intervals of 0 to 50 megohms, 50 to 100 megohms, and 100 to 150 megohms, respectively. The characteristic component within each interval reflects the correlation between insulation degradation and signal transmission loss within that interval. The interval in which the insulation resistance under test falls is matched with these characteristic components, and the matched characteristic component is determined as the appropriate impedance coefficient. For example, if the insulation resistance under test is 75 megohms, falling within the 50 to 100 megohms interval, the characteristic component corresponding to this interval is the appropriate impedance coefficient.

[0029] The actual measured insulation resistance value is corrected based on the inherent characteristics of the insulating medium within the switchgear under test. These inherent characteristics include medium type, aging degree, temperature sensitivity, and humidity adaptability. These characteristics affect the actual insulation resistance performance. For example, epoxy resin insulation performance degrades at high temperatures, while silicone rubber insulation is more sensitive to humidity. The correction process compensates for the original insulation resistance under test using inherent characteristic parameters. The corrected insulation resistance value = measured insulation resistance value × medium correction factor, where the medium correction factor is an adjustment parameter calibrated based on the inherent characteristics of the insulating medium.

[0030] Identifying the type and basic characteristics of the insulating medium, such as epoxy resin, silicone rubber, and cross-linked polyethylene, is crucial. Different media exhibit significant differences in conductivity, temperature sensitivity, and humidity tolerance, which forms the basis for determining correction factors. For example, epoxy resin exhibits significant insulation performance degradation at high temperatures, while silicone rubber is more sensitive to humidity changes. The reference insulation resistance value of the medium under standard operating conditions is collected. Standard operating conditions typically refer to an ideal state with a temperature of 25 degrees Celsius, a relative humidity of 60%, and no load. This value serves as the benchmark for subsequent corrections. Actual environmental parameters under the current operating conditions are measured, such as temperature, humidity, equipment operating time, and load status. These parameters are then compared with those under the standard operating conditions to calculate the deviation values ​​for each parameter. For example, the actual temperature is 35 degrees Celsius, and the deviation from the reference temperature is 10 degrees Celsius; the actual humidity is 70%, and the deviation from the reference humidity is 10%.

[0031] The influence coefficients corresponding to each deviation are calibrated according to the characteristics of the medium, such as the temperature influence coefficient, humidity influence coefficient, and aging influence coefficient. These coefficients reflect the degree of influence of a unit deviation on the insulation performance of the medium. For example, the temperature influence coefficient of epoxy resin medium is 0.002, and the humidity influence coefficient is 0.0015.

[0032] The dielectric correction factor = 1 - (temperature deviation × temperature influence coefficient + humidity deviation × humidity influence coefficient + aging deviation × aging influence coefficient). For example, if the temperature deviation is 10 degrees Celsius and the humidity deviation is 10%, the dielectric correction factor is 1 - (10 × 0.002 + 10 × 0.0015) = 1 - 0.035 = 0.965. This factor is used to correct the insulation resistance value to be measured, making it more closely reflect the actual insulation performance of the dielectric under actual working conditions.

[0033] For example, if the insulation resistance to be tested is 75 megohms and the insulating medium is epoxy resin with a medium correction factor of 0.95, the corrected insulation resistance value is calculated to be 75 × 0.95 = 71.25 megohms. This corrected value more accurately reflects the actual insulation performance of the insulating medium under the current operating conditions.

[0034] The modified insulation resistance value is transformed into a loss-related value based on the adaptive attenuation coefficient. The modified insulation resistance value is correlated with the adaptive attenuation coefficient to obtain the basic signal transmission loss value corresponding to insulation degradation. The basic attenuation value = modified insulation resistance value × adaptive attenuation coefficient. For example, if the modified insulation resistance value is 71.25 megohms and the adaptive attenuation coefficient is 0.6% / megohm, the calculated basic attenuation value = 71.25 × 0.6% = 0.4275. This value represents the basic degree of signal transmission loss under the current insulation degradation state.

[0035] The basic impedance value is adjusted for loss compensation. Environmental factors, load fluctuations, and impedance changes in the signal transmission path during switchgear operation affect the degree of signal transmission loss based on the basic impedance value. Signal transmission impedance value = basic impedance value + operating condition compensation value, where the operating condition compensation value is an adjustment amount calculated based on actual operating condition parameters.

[0036] The operating condition compensation value is based on various actual operating condition parameters of the switchgear during operation. It quantifies the impact of each parameter on signal transmission loss and then weights and fuses these parameters to obtain the final adjustment amount. The calculation process incorporates the operating condition dimensions of the environment, load, and the equipment's own status to ensure that the compensation value is suitable for the actual operating scenario. Operating condition compensation value = Environmental operating condition compensation amount + Load operating condition compensation amount + Equipment operating condition compensation amount.

[0037] The calculation of environmental condition compensation focuses on environmental parameters such as temperature and humidity. These two parameters directly alter the conductivity of the insulating medium, thereby indirectly affecting signal transmission loss. First, baseline values ​​for temperature and humidity are determined. These baseline values ​​represent the standard operating environment parameters for the switchgear design; for example, a baseline temperature of 25 degrees Celsius and a baseline humidity of 60%. Then, the actual temperature and humidity values ​​of the current environment are measured, and the temperature deviation and humidity deviation values ​​are calculated respectively: temperature deviation = actual temperature - baseline temperature value; humidity deviation = actual humidity value - baseline humidity value. Based on the characteristics of the switchgear's insulating medium, temperature and humidity influence coefficients are calibrated. For example, the temperature influence coefficient for epoxy resin media is 0.002, and the humidity influence coefficient is 0.0015. Environmental condition compensation = temperature deviation value × temperature influence coefficient + humidity deviation value × humidity influence coefficient. For example, if the actual temperature is 35 degrees Celsius and the actual humidity is 70%, the temperature deviation value = 35 - 25 = 10, and the humidity deviation value = 70 - 60 = 10. Substituting these values, we can obtain the environmental condition compensation = 10 × 0.002 + 10 × 0.0015 = 0.035.

[0038] The calculation of load condition compensation revolves around the actual load current of the switchgear. Fluctuations in load current cause changes in cabinet temperature and electromagnetic induction intensity, thus increasing signal transmission loss. First, the rated load current of the switchgear is determined as the load reference value, for example, a rated load current of 630 amps. The actual load current value of the current switchgear is then measured, and the load deviation value is calculated: Load deviation value = Actual load current value - Rated load current value. Next, the load influence coefficient is calibrated based on the impedance characteristics of the signal transmission path. This coefficient reflects the degree of influence of a unit load deviation on signal transmission loss; for example, the load influence coefficient is 0.0001. The load condition compensation amount = Load deviation value × Load influence coefficient. For example, if the actual load current is 730 amps, the load deviation value = 730 - 630 = 100. Substituting this, the load condition compensation amount = 100 × 0.0001 = 0.01.

[0039] The calculation of equipment operating condition compensation needs to be based on the aging state of the switchgear itself, mainly referring to the equipment's operating time and the cabinet's vibration amplitude. Operating time determines the degree of aging of the insulation medium and transmission lines, while cabinet vibration exacerbates contact loss in the signal transmission path. First, determine the baseline values ​​for the equipment's operating time and vibration amplitude, for example, a baseline operating time of 10,000 hours and a baseline vibration amplitude of 0.1 mm. Then, detect the actual operating time and actual vibration amplitude of the current equipment, and calculate the time deviation and vibration deviation values ​​respectively. Time deviation = actual operating time - baseline operating time value; vibration deviation = actual vibration amplitude - baseline vibration amplitude value. Based on the switchgear's equipment material and structural design, calibrate the time influence coefficient and vibration influence coefficient, for example, a time influence coefficient of 0.00005 and a vibration influence coefficient of 0.02. Equipment operating condition compensation = duration deviation value × duration influence coefficient + vibration deviation value × vibration influence coefficient. For example, if the actual operating time is 20,000 hours and the actual vibration amplitude is 0.15 mm, the duration deviation value = 20,000 - 10,000 = 10,000, and the vibration deviation value = 0.15 - 0.1 = 0.05. Substituting these values, we can obtain the equipment operating condition compensation value = 10,000 × 0.00005 + 0.05 × 0.02 = 0.5 + 0.001 = 0.501.

[0040] The final operating condition compensation value is obtained by summing the three compensation items mentioned above: Operating condition compensation value = 0.035 + 0.01 + 0.501 = 0.546. The signal transmission attenuation value is then calculated. This value characterizes the degree of signal transmission loss within the switchgear under test, providing a quantitative basis for subsequent fault analysis.

[0041] It also includes the following steps: The degree of insulation state deviation is obtained by identifying the trend of the change in the corrected insulation resistance value from the reference state. The impedance change in signal transmission impedance due to the degree of insulation state deviation is determined based on the adaptation impedance coefficient. The impedance change value is compared with the tolerance threshold of the signal transmission path; If the impedance change value does not exceed the tolerance threshold, it is determined that the insulation resistance under test does not have an impedance disturbance effect on the signal transmission path inside the cabinet. If the impedance change exceeds the tolerance threshold, it is determined that the insulation resistance under test has an impedance disturbance effect on the signal transmission path inside the cabinet.

[0042] First, it is necessary to determine the baseline state for the corrected insulation resistance value. This baseline state is typically the insulation resistance value of the switchgear under stable operating conditions when the insulating medium is in a standard state, such as the standard insulation resistance value under rated operating conditions. Then, through continuous monitoring or comparison with historical data, the trend of the corrected insulation resistance value deviating from this baseline state is identified, including the direction and magnitude of the deviation, thus obtaining the degree of insulation state deviation. Insulation state deviation degree = Corrected insulation resistance value - Baseline insulation resistance value. A negative result indicates a decrease in insulation resistance and a deterioration in insulation condition; a positive result indicates an increase in insulation resistance and an improvement in insulation condition. For example, if the baseline insulation resistance value is 100 megohms and the corrected insulation resistance value is 71.25 megohms, the calculated insulation state deviation degree = 71.25 - 100 = -28.75 megohms. This negative value indicates a deterioration in the insulation condition.

[0043] The degree of insulation state deviation needs to be converted into a numerical value representing its impact on signal transmission impedance based on the adaptation impedance coefficient. The adaptation impedance coefficient is a quantitative correlation parameter between insulation degradation and changes in signal transmission impedance. This coefficient is used to calculate the magnitude of the impedance change caused by the insulation state deviation. Impedance change value = Insulation state deviation degree × Adaptive impedance coefficient. For example, if the insulation state deviation degree is -28.75 megohms, and the sum of historical signal transmission losses in the 50-100 megohms range is 30%, and the sum of resistance change amplitudes is 50 megohms, then the characteristic component for this range can be calculated as 30% / 50 megohms = 0.6% / megohm. This value represents the characteristic component for this range.

[0044] The specific range to which the insulation resistance value to be measured belongs is determined by comparing it with the range boundary value. For example, if the insulation resistance value to be measured is 75 megohms, it is determined to be within the range of 50 to 100 megohms after comparison. Finally, the characteristic component corresponding to this range is directly used as the adaptation impedance coefficient, where the adaptation impedance coefficient = characteristic component of the 50 to 100 megohm range = 0.6% / megohm.

[0045] First, it's necessary to determine the tolerance threshold of the signal transmission path. This threshold represents the maximum impedance change the path can withstand; exceeding it will lead to signal transmission abnormalities. The tolerance threshold needs to be determined in conjunction with the switchgear design standards, the material and diameter of the signal transmission line, and the type of signal being transmitted. For example, the tolerance threshold for a signal transmission path in a certain switchgear might be 0.5 ohms. Then, the absolute value of the impedance change is compared to the tolerance threshold to determine if the impedance change exceeds the tolerance range.

[0046] If the absolute value of the impedance change does not exceed the tolerance threshold, it is determined that the insulation resistance under test does not affect the impedance disturbance of the signal transmission path inside the cabinet. For example, if the impedance change is -0.575 ohms and its absolute value is 0.575 ohms, and the tolerance threshold is 0.6 ohms, since 0.575 < 0.6, it indicates that the impedance change is still within the tolerance range and will not disturb the signal transmission path.

[0047] If the absolute value of the impedance change exceeds the tolerance threshold, it is determined that the insulation resistance under test has an impedance disturbance effect on the signal transmission path inside the cabinet. For example, if the impedance change is -0.575 ohms, its absolute value is 0.575 ohms. If the tolerance threshold is 0.5 ohms, since 0.575 > 0.5, it indicates that the impedance change exceeds the acceptable range, thus disturbing the signal transmission path and affecting the stability of signal transmission.

[0048] The first condition influence value is obtained based on the perturbation coefficient, the electromagnetic interference intensity under test, and the signal transmission attenuation value, specifically including the following steps: The mapping relationship between the perturbation coefficient and the control command distortion is defined as the normalized perturbation coefficient; The actual conduction path and range of electromagnetic interference inside the switchgear are determined. Based on the actual conduction path, range, and regular perturbation coefficient, the intensity of electromagnetic interference on the other side is transformed by distortion mapping to obtain the basic interference parameters characterizing the degree of disturbance to control commands. The basic interference parameters and signal transmission attenuation values ​​are coupled and fused to obtain the comprehensive state parameters. The comprehensive state parameters are then modified according to the operating conditions to obtain the first condition influence value.

[0049] First, it is necessary to clarify the mapping relationship between the perturbation coefficient and control command distortion. The original perturbation coefficient is based on the ratio of electromagnetic interference intensity to control command distortion value, but this coefficient does not fully consider the differences in interference propagation under different operating conditions. The normalized perturbation coefficient is a standardization process of the original mapping relationship, eliminating the influence of differences in operating conditions, so that the coefficient can reflect the essential correlation between electromagnetic interference and control command distortion. In practice, the perturbation coefficients of different operating conditions in historical data are statistically analyzed, outliers are removed, and normalization is performed to obtain the normalized mapping relationship, which is the normalized perturbation coefficient. For example, if the original perturbation coefficient fluctuates from 0.18% to 0.22% / dB / µV under different operating conditions, the normalized perturbation coefficient is determined to be 0.2% / dB / µV. This coefficient stably reflects the degree of correlation between electromagnetic interference and control command distortion.

[0050] The actual conduction path and effective range of electromagnetic interference (EMI) within the switchgear are determined. The actual conduction path refers to the physical path of EMI propagation from the interference source to the point of control command distortion, such as the line path from a partial discharge point at a busbar connector to the intelligent measurement and control unit. The effective range refers to the area affected by the interference, such as affecting only a control module in a specific circuit or a control unit covering the entire switchgear. Based on the actual conduction path, effective range, and regularized perturbation coefficient, the intensity of the EMI under test is transformed using distortion mapping to obtain the basic interference parameters characterizing the degree of control command disturbance. Basic interference parameters = EMI intensity under test × regularized perturbation coefficient × path attenuation coefficient × range influence coefficient, where the path attenuation coefficient reflects the degree of attenuation of the interference in the actual conduction path, and the range influence coefficient reflects the coverage ratio of the interference's effective range.

[0051] The path attenuation coefficient requires determining the actual propagation path of electromagnetic interference, i.e., the physical propagation channel from the interference source to the point of control command distortion. For example, this could be the route from a partial discharge point at a busbar joint to the intelligent monitoring and control unit, or the electromagnetic radiation path from the circuit breaker operating mechanism to the control circuit. The physical characteristics of this path must be assessed, including path length, dielectric type, shielding structure, and number of bends, as these factors directly affect the degree of electromagnetic interference propagation attenuation. For instance, the interference attenuation significantly increases when the path contains a metallic shielding layer; the longer the path, the greater the attenuation. The path attenuation coefficient = 1 - (path length × dielectric attenuation coefficient + shielding attenuation value + bend attenuation value), where the dielectric attenuation coefficient, shielding attenuation value, and bend attenuation value are all determined based on the actual characteristics of the path. For example, with a path length of 2 meters, a dielectric attenuation coefficient of 0.02 / meter, a shielding attenuation value of 0.1, and a bend attenuation value of 0.05, the path attenuation coefficient = 1 - (2 × 0.02 + 0.1 + 0.05) = 1 - 0.19 = 0.81.

[0052] It is necessary to determine the effective range of electromagnetic interference, i.e., the spatial coverage area of ​​the interference inside the switchgear and the degree of overlap between this area and the control command distortion area. For example, if the electromagnetic radiation generated by the interference source only covers the left side of the switchgear, while the control command distortion area is located on the right side, the overlap ratio between the effective range and the distortion area is low. If the interference source is located near the distortion area without shielding, the effective range completely covers the distortion area. In specific assessments, a spatial distribution heat map of the interference is drawn after electromagnetic simulation or on-site testing. The area percentage of the distortion area within the interference's effective range is calculated; this percentage is the range influence coefficient, calculated as: Interference-covered area of ​​the distortion area / Total area of ​​the distortion area. For example, if the total area of ​​the distortion area is 0.5 square meters and the interference-covered area is 0.4 square meters, the range influence coefficient is 0.4 / 0.5 = 0.8, representing an 80% influence ratio of the interference on the control command distortion area.

[0053] For example, if the electromagnetic interference intensity to be measured is 50 dB / µV, the normalization perturbation coefficient is 0.2% / dB / µV, the path attenuation coefficient is 0.9, and the range influence coefficient is 0.8, the basic interference parameter can be calculated as 50 × 0.2% × 0.9 × 0.8 = 0.072. This value represents the basic degree to which the control command is affected by electromagnetic interference.

[0054] It is necessary to couple and fuse the basic interference parameters and the signal transmission attenuation value. The signal transmission attenuation value characterizes the degree of signal transmission loss caused by insulation degradation, while the basic interference parameter characterizes the degree of control command interference caused by electromagnetic interference. The coupling and fusion of the two can comprehensively reflect the abnormal operating state of the switchgear. The comprehensive state parameter = basic interference parameter + signal transmission attenuation value. For example, if the basic interference parameter is 0.072 and the signal transmission attenuation value is 0.4775, the calculated comprehensive state parameter = 0.072 + 0.4775 = 0.5495. This value comprehensively reflects the operating state of the switchgear under the combined effects of insulation degradation and electromagnetic interference.

[0055] Perform operating condition adaptation correction on the comprehensive status parameters. Operating condition adaptation correction involves adjusting the comprehensive status parameters based on the current operating conditions of the switchgear to eliminate the impact of differences in operating conditions and make the results more consistent with the actual operating conditions. The first condition influence value = comprehensive status parameter × operating condition correction coefficient, where the operating condition correction coefficient is an adjustment parameter calibrated based on current operating condition parameters such as temperature, humidity, and load.

[0056] It is necessary to clearly define the environmental conditions, load conditions, and equipment aging conditions for the operating condition correction factor. The environmental conditions include temperature and humidity, the load conditions focus on the actual load current, and the equipment aging conditions refer to the equipment operating time and cabinet vibration amplitude.

[0057] In the quantification of the impact of environmental conditions, the first step is to determine the baseline values ​​for temperature and humidity, typically the standard operating parameters designed for the switchgear. For example, the baseline temperature value is 25 degrees Celsius, and the baseline humidity value is 60%. Then, the actual temperature and humidity values ​​of the current environment are measured, and the temperature deviation and humidity deviation values ​​are calculated separately: temperature deviation = actual temperature value - baseline temperature value; humidity deviation = actual humidity value - baseline humidity value. Based on the characteristics of the switchgear's insulating medium and electronic components, the weights for temperature and humidity effects are calibrated. For example, the temperature effect weight for epoxy resin media is 0.4, and the humidity effect weight is 0.3.

[0058] In the quantification of the load condition impact, the rated load current of the switchgear is used as the load reference value, for example, the rated load current is 630 amps. The current actual load current value is detected, and the load deviation value = actual load current value - rated load current value. Then, the load impact weight is calibrated according to the impedance characteristics of the signal transmission path, for example, the load impact weight is 0.2.

[0059] In the quantification phase of assessing the impact of equipment aging conditions, baseline values ​​for equipment operating time and vibration amplitude are determined. For example, the baseline operating time might be 10,000 hours, and the baseline vibration amplitude 0.1 mm. After detecting the current actual operating time and actual vibration amplitude, the time deviation and vibration deviation are calculated respectively: Time deviation = Actual operating time - Baseline operating time; Vibration deviation = Actual vibration amplitude - Baseline vibration amplitude. Based on the switchgear's material and structural design, the weights for the impact of operating time and vibration are calibrated. For example, the weight for the impact of operating time might be 0.08, and the weight for the impact of vibration 0.02, representing the proportion of equipment aging conditions in the overall correction.

[0060] The comprehensive operating condition impact value is obtained by multiplying the deviation values ​​of each operating condition dimension by their corresponding weights and summing the results. Then, the operating condition correction coefficient is obtained by subtracting this comprehensive operating condition impact value from 1. Operating condition correction coefficient = 1 - (temperature deviation value × temperature impact weight + humidity deviation value × humidity impact weight + load deviation value × load impact weight + duration deviation value × duration impact weight + vibration deviation value × vibration impact weight). For example, if the actual temperature is 35 degrees Celsius, the actual humidity is 70%, the actual load current is 730 amps, the actual operating time is 20,000 hours, and the actual vibration amplitude is 0.15 mm, after substituting these values, we get the following values: temperature deviation = 10, humidity deviation = 10, load deviation = 100, operating time deviation = 10,000, vibration deviation = 0.05. The comprehensive operating condition influence value is calculated as follows: 10 × 0.4 + 10 × 0.3 + 100 × 0.2 + 10,000 × 0.08 + 0.05 × 0.02 = 4 + 3 + 20 + 800 + 0.001 = 827.00. The operating condition correction factor is calculated as 1 - 827.001 = -826.001. At this point, the result needs to be normalized to limit it to the range of 0 to 1. For example, by linear scaling, the corrected operating condition correction factor is 0.98.

[0061] For example, if the comprehensive state parameter is 0.5495 and the current operating condition correction coefficient is 0.98, the first condition influence value can be calculated as 0.5495 × 0.98 ≈ 0.5385, which characterizes the degree of abnormal operation of the switchgear when the insulation resistance under test does not generate impedance disturbance.

[0062] Based on the amplitude and direction of the cabinet vibration resonance of the location inside the switchgear to which the electromagnetic interference intensity is to be measured, the influence of vibration resonance on the interference intensity of that location in the switchgear is determined. This involves the following steps: Locate the target location inside the switch cabinet corresponding to the intensity of the electromagnetic interference to be measured, collect the cabinet vibration resonance amplitude corresponding to the target location, and perform amplitude normalization processing on the cabinet vibration resonance amplitude to obtain the standard resonance amplitude. The relative relationship between the resonance direction and the signal transmission direction at the target location is determined, and the guiding effect of the resonance direction on the electromagnetic interference propagation path is judged based on the relative relationship to obtain the resonance guiding characteristics. Using the resonance guiding characteristics as a constraint, and combining the vibration intensity of the standard resonance amplitude, the preliminary parameters of the resonance effect on electromagnetic interference are obtained. By correlating and fusing the preliminary operating parameters with the electromagnetic interference intensity to be measured, the influence value of the interference intensity of this part of the switch cabinet under test due to vibration resonance is obtained.

[0063] First, it is necessary to locate the target location inside the switchgear corresponding to the intensity of the electromagnetic interference to be measured. This target location is the core area where the electromagnetic interference is generated or acts, such as the intelligent monitoring and control unit or the circuit breaker control circuit. The location process relies on the spatial positioning function of the electromagnetic interference detection equipment to pinpoint the physical location corresponding to the interference intensity. Next, the cabinet vibration resonance amplitude corresponding to the target location is collected. This amplitude reflects the vibration resonance intensity of the cabinet under the current operating conditions and can be obtained in real time through vibration sensors. To eliminate the dimensional differences in vibration amplitude under different operating conditions, the cabinet vibration resonance amplitude needs to be normalized to obtain a standard resonance amplitude. Standard resonance amplitude = cabinet vibration resonance amplitude / maximum allowable resonance amplitude, where the maximum allowable resonance amplitude is the vibration tolerance limit value specified during the switchgear design. For example, if the cabinet vibration resonance amplitude is 0.2 mm and the maximum allowable resonance amplitude is 0.5 mm, the standard resonance amplitude is calculated as 0.2 / 0.5 = 0.4, which normalizes the vibration intensity to the range of 0 to 1.

[0064] It is necessary to clarify the relative relationship between the resonance direction and the signal transmission direction of the target area. The resonance direction is the main direction of cabinet vibration, such as the horizontal or vertical direction along the switch cabinet; the signal transmission direction is the physical path direction of signal transmission within the target area, such as the line direction from left to right. The guiding effect of the resonance direction on the electromagnetic interference propagation path is determined by comparing the angle between the two directions: if the resonance direction is consistent with the signal transmission direction, it enhances the propagation of interference along the transmission path; if the direction is perpendicular, it weakens the directional propagation of interference. The resonance guiding characteristic is extracted based on the relative relationship. This characteristic is usually represented by a value between 0 and 1; the closer the value is to 1, the stronger the guiding effect of the resonance direction on interference propagation. For example, if the angle between the resonance direction and the signal transmission direction is 30 degrees, and the resonance guiding characteristic is obtained as 0.8 according to the preset angle-feature value mapping rule, it indicates that the resonance direction has a strong positive guiding effect on interference propagation.

[0065] Using the resonance guidance characteristics as a constraint, and combining the vibration intensity with the standard resonance amplitude, the preliminary effect parameter of resonance on electromagnetic interference is obtained. This parameter quantifies the initial amplification or suppression effect of vibration resonance on electromagnetic interference. The preliminary effect parameter = standard resonance amplitude × resonance guidance characteristics. For example, if the standard resonance amplitude is 0.4 and the resonance guidance characteristics are 0.8, the calculated preliminary effect parameter = 0.4 × 0.8 = 0.32. This value represents the initial degree of influence of vibration resonance on electromagnetic interference.

[0066] By correlating and fusing the preliminary action parameters with the electromagnetic interference intensity to be measured, the influence value of the interference intensity caused by vibration resonance on that part of the switchgear under test is obtained. Correlation and fusing involves adding the effect of vibration resonance to the original electromagnetic interference intensity. The influence value of the interference intensity is calculated as: Electromagnetic interference intensity to be measured × (1 + preliminary action parameters). For example, if the electromagnetic interference intensity to be measured is 50 dB / µV and the preliminary action parameter is 0.32, the influence value of the interference intensity is calculated to be 50 × (1 + 0.32) = 66 dB / µV. This value reflects the actual interference intensity experienced by the target part after vibration resonance.

[0067] The second condition influence value is obtained based on the interference intensity condition influence value, the electromagnetic interference intensity under test, the perturbation coefficient, and the signal transmission attenuation value. This process includes the following steps: Based on the vibration resonance characteristics corresponding to the influence value of the interference intensity, the characteristic parameters of the perturbation coefficient are adjusted to obtain the resonance adaptation perturbation coefficient. The influence value of the interference intensity condition is correlated with the electromagnetic interference intensity to be measured and calibrated to obtain the corrected electromagnetic interference intensity. The modified electromagnetic interference intensity is correlated with the resonant adaptation perturbation coefficient to obtain the resonant adaptation perturbation coefficient and the resonant modified electromagnetic interference intensity. By combining the interference state of the resonance-corrected electromagnetic interference intensity with the characterization of the signal transmission attenuation value, the attenuation value after disturbance correction is obtained. The distortion effect parameter is progressively fused with the disturbance-corrected attenuation value to obtain the second state effect value.

[0068] First, it is necessary to extract the vibration resonance characteristics corresponding to the influence value of the interference intensity. These characteristics include the standard resonance amplitude and resonance guidance characteristics, reflecting the influence of vibration resonance on the propagation of electromagnetic interference. Based on the vibration resonance characteristics, the characteristic parameters of the perturbation coefficient are adjusted to obtain the resonance-adapted perturbation coefficient. The amplification or guiding effect of vibration resonance on interference propagation is incorporated into the perturbation coefficient, enabling the coefficient to reflect the correlation between electromagnetic interference and control command distortion under the influence of resonance. Resonance-adapted perturbation coefficient = regularized perturbation coefficient × (1 + resonance guidance characteristics × standard resonance amplitude).

[0069] A smaller angle indicates a more significant guiding and enhancing effect of the resonance direction on the propagation of electromagnetic interference. Based on a preset mapping relationship between the angle and the guiding strength, the resonance guiding characteristics are obtained. For example, when the angle between the resonance direction and the signal transmission path is 30 degrees, its guiding strength is calibrated to be 0.8, which is the resonance guiding characteristic. The cabinet vibration resonance amplitude is collected at the target location, and then normalized to the maximum allowable resonance amplitude specified in the switchgear design. The standard resonance amplitude = cabinet vibration resonance amplitude / maximum allowable resonance amplitude. For example, if the collected cabinet vibration resonance amplitude is 0.2 mm and the maximum allowable resonance amplitude is 0.5 mm, the standard resonance amplitude can be calculated as 0.2 / 0.5 = 0.4.

[0070] For example, if the regularization perturbation coefficient is 0.2% / dB / µV, the resonance conduction characteristic is 0.8, and the standard resonance amplitude is 0.4, the resonance adaptation perturbation coefficient can be calculated as 0.2% × (1 + 0.8 × 0.4) = 0.2% × 1.32 = 0.264% / dB / µV.

[0071] The interference intensity condition influence value is correlated with the measured electromagnetic interference intensity for calibration. The interference intensity condition influence value characterizes the interference intensity after vibration resonance, while the measured electromagnetic interference intensity is the original interference intensity. The correlation calibration eliminates the redundant calculations caused by resonance effects, thus obtaining the corrected electromagnetic interference intensity. Corrected electromagnetic interference intensity = Interference intensity condition influence value - Measured electromagnetic interference intensity. For example, if the interference intensity condition influence value is 66 dB / µV and the measured electromagnetic interference intensity is 50 dB / µV, the calculated corrected electromagnetic interference intensity = 66 - 50 = 16 dB / µV. This value represents the additional interference intensity superimposed by vibration resonance.

[0072] The distortion impact parameter is obtained by correlating and transforming the corrected electromagnetic interference intensity with the resonant adaptation perturbation coefficient. This parameter quantifies the degree of influence of the resonant-corrected electromagnetic interference on control command distortion. Distortion impact parameter = Corrected electromagnetic interference intensity × Resonant adaptation perturbation coefficient. For example, if the corrected electromagnetic interference intensity is 16 dB / µV and the resonant adaptation perturbation coefficient is 0.264% / dB / µV, the distortion impact parameter can be calculated as 16 × 0.264% = 0.04224.

[0073] The signal transmission attenuation value is characterized by adjusting the interference state based on the resonant correction electromagnetic interference intensity. The resonant correction electromagnetic interference intensity causes impedance fluctuations in the signal transmission path, thus affecting the actual performance of the signal transmission attenuation value. Therefore, it is necessary to perform perturbation correction on the signal transmission attenuation value. The attenuation value after perturbation correction = signal transmission attenuation value × (1 + resonant correction electromagnetic interference intensity × impedance perturbation coefficient), where the impedance perturbation coefficient reflects the degree of perturbation of the signal transmission attenuation value by the interference intensity. For example, if the signal transmission attenuation value is 0.4775, the resonant correction electromagnetic interference intensity is 16 dB / µV, and the impedance perturbation coefficient is 0.005, the calculated attenuation value after perturbation correction is 0.4775 × (1 + 16 × 0.005) ≈ 0.5157. This value represents the signal transmission attenuation value after interference perturbation correction.

[0074] The second condition influence value is obtained by progressively fusing the distortion influence parameter with the disturbance-corrected impedance value. The core of this progressive fusion is to superimpose the interference distortion influence after resonance correction with the signal transmission impedance value after disturbance correction, comprehensively reflecting the abnormal operating state of the switchgear caused by the combined effects of insulation degradation, electromagnetic interference, and vibration resonance. The second condition influence value = distortion influence parameter + disturbance-corrected impedance value. For example, if the distortion influence parameter is 0.04224 and the disturbance-corrected impedance value is 0.5157, the second condition influence value can be calculated as 0.04224 + 0.5157 ≈ 0.5579. This value characterizes the overall degree of abnormal operation of the switchgear when the measured insulation resistance generates impedance disturbances.

[0075] After processing and analyzing the impact values ​​of the first condition, the second condition, and the initial detection and control performance values ​​of the switchgear under test, the switchgear fault early warning result is output, which specifically includes the following steps: Based on the stable operation performance of the switchgear, the initial detection and control performance values ​​of the switchgear under test are reconstructed to obtain the performance benchmark value. Based on the performance benchmark value, the operational anomaly characteristics represented by the first or second condition influence value are mapped to the performance benchmark system to obtain the fused state parameters. Stable fusion parameters are obtained by stability screening of the fusion state parameters; The results of hazard location analysis are obtained by tracing and locating potential hazards based on stable fusion parameters, determining the location and impact range of the hazards. Based on the hazard location results, the operational risks of the switchgear are assessed to obtain switchgear fault early warning results.

[0076] First, it is necessary to reconstruct the initial detection and control performance values ​​based on the stable operation performance of the switchgear. The initial detection and control performance values ​​are the basic performance parameters calibrated after the switchgear leaves the factory or undergoes maintenance. Stable operation performance refers to the actual performance data of the switchgear under long-term, fault-free operation conditions, such as signal transmission loss rate, control command accuracy, and response time. Baseline reconstruction involves removing the initial performance values ​​from the standard operating conditions and incorporating the actual stable operation performance characteristics to obtain a more realistic performance baseline value. Performance baseline value = Initial detection and control performance value × Stable operation correction factor, where the stable operation correction factor is an adjustment parameter obtained based on historical stable operation data. For example, if the initial detection and control performance value is 0.9 and the stable operation correction factor is 0.95, the calculated performance baseline value = 0.9 × 0.95 = 0.855. This value represents the ideal performance baseline of the switchgear under stable operation conditions.

[0077] Based on the performance benchmark value, the operational anomaly characteristics represented by the first or second condition influence value are mapped to the performance benchmark system. The first and second condition influence values ​​represent the degree of operational anomaly in scenarios with and without impedance disturbances, respectively. The mapping process transforms the degree of anomaly into the degree of deviation from the performance benchmark value. The fused state parameter = performance benchmark value - (first or second condition influence value). For example, if the performance benchmark value is 0.855 and the second condition influence value is 0.5579, the fused state parameter can be calculated as 0.855 - 0.5579 = 0.2971. This value reflects the degree of deviation between the actual performance of the switchgear under abnormal conditions and the benchmark performance.

[0078] Stability screening of the fusion status parameters is necessary. Stability screening eliminates parameter anomalies caused by instantaneous operating condition fluctuations, ensuring that the parameters reflect the continuous operating status of the switchgear. Specifically, a moving average is applied to the fusion status parameters over multiple consecutive detection cycles to remove abnormal fluctuations, thus obtaining stable fusion parameters. Stable fusion parameter = (fusion status parameter 1 + fusion status parameter 2 + ... + fusion status parameter n) / n, where n is the number of detection cycles. For example, if the fusion status parameters for three consecutive cycles are 0.2971, 0.3012, and 0.2985, the stable fusion parameter can be calculated as (0.2971 + 0.3012 + 0.2985) / 3 ≈ 0.2989, which represents a stable abnormal operating state of the switchgear.

[0079] In the hazard location determination stage, the stable fusion parameters are used to trace and locate the hazard source. The core of this stage is to determine the specific location and impact range of the hazard by analyzing the magnitude and trend of the stable fusion parameters, combined with the switchgear's structural layout and monitoring data. For example, if the stable fusion parameter is 0.2989, far below the performance benchmark value, and data shows that this parameter is mainly contributed by signal transmission attenuation and interference intensity, then the hazard can be determined to be located in the signal transmission area and electromagnetic interference-sensitive areas, with the impact range covering related control loops. Specific methods for hazard location include parameter contribution analysis and location correlation mapping, ultimately yielding a clear hazard location result.

[0080] In the fault warning result evaluation stage, the operational risk of the switchgear is assessed based on the hazard location results. The evaluation process considers the severity, scope of impact, and development trend of the hazard, classifying operational risks into different levels, such as minor, general, and severe hazards, and outputting corresponding fault warning results. For example, if a hazard is located in a critical control loop, has a wide impact range, and develops rapidly, it is assessed as a severe hazard, and a red fault warning is output; if a hazard is located in a non-critical area, has a small impact range, and develops slowly, it is assessed as a minor hazard, and a blue warning is output. The switchgear fault warning results obtained through risk assessment provide reliable decision-making basis for maintenance personnel.

[0081] A switchgear fault detection system, comprising: Acquisition module: Acquires the insulation resistance and electromagnetic interference intensity of the switchgear under test; Extraction and processing module: Extracts and processes historical detection data related to switchgear faults to obtain the attenuation coefficient between insulation resistance and signal transmission loss, as well as the perturbation coefficient between electromagnetic interference intensity and control command distortion. First processing module: Obtains the signal transmission attenuation value that affects the signal transmission loss in the switch cabinet under test based on the attenuation coefficient and the insulation resistance to be measured; Second processing module: If the insulation resistance to be measured does not affect the impedance disturbance of the signal transmission path in the cabinet, the first condition influence value is obtained based on the perturbation coefficient, the electromagnetic interference intensity to be measured and the signal transmission attenuation value. The third processing module: If the insulation resistance to be tested causes impedance disturbance to the signal transmission path inside the cabinet, the module determines the interference intensity status of the part of the switch cabinet to be tested affected by vibration resonance based on the cabinet vibration resonance amplitude and resonance direction of the location of the electromagnetic interference intensity to be tested; and obtains the second status influence value based on the interference intensity status influence value, the electromagnetic interference intensity to be tested, the disturbance coefficient and the signal transmission attenuation value. Output module: Processes the first condition influence value, the second condition influence value, and the initial detection and control performance value of the switchgear under test, and outputs the switchgear fault early warning result.

[0082] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0083] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A switchgear failure detection method characterized by, The method includes the following steps: The insulation resistance and electromagnetic interference intensity of the switchgear under test are collected. Historical detection data related to switchgear faults are extracted and processed to obtain the attenuation coefficient between insulation resistance and signal transmission loss, as well as the perturbation coefficient between electromagnetic interference intensity and control command distortion. The signal transmission attenuation value affecting the signal transmission loss in the switch cabinet under test is obtained based on the attenuation coefficient and the insulation resistance to be measured. If the insulation resistance under test does not affect the impedance disturbance of the signal transmission path inside the cabinet, the first condition influence value can be obtained based on the disturbance coefficient, the electromagnetic interference intensity under test, and the signal transmission attenuation value. If the insulation resistance under test causes impedance disturbance to the signal transmission path inside the cabinet, the interference intensity of the part of the switch cabinet under test affected by vibration resonance is determined based on the cabinet vibration resonance amplitude and resonance direction of the part of the switch cabinet under test to which the electromagnetic interference intensity belongs. The second influence value is obtained based on the interference intensity influence value, the electromagnetic interference intensity under test, the perturbation coefficient and the signal transmission attenuation value. After processing and analyzing the impact values ​​of the first condition, the impact values ​​of the second condition, and the initial detection and control performance values ​​of the switchgear under test, the switchgear fault early warning result is output.

2. The switchgear fault detection method of claim 1, wherein, The process of collecting the insulation resistance and electromagnetic interference intensity of the switchgear under test includes the following steps: The insulation resistance value is obtained by detecting the insulation resistance of the signal transmission parts inside the switch cabinet under test; Extract the loss resistance threshold that insulation resistance causes signal transmission loss in the switchgear; The insulation resistance value that is less than the loss resistance threshold is determined as the insulation resistance to be measured; The electromagnetic interference intensity under test is obtained by detecting the electromagnetic interference intensity at the location of control command distortion in the switch cabinet under test.

3. The switchgear fault detection method according to claim 1, characterized in that, The historical detection data related to switchgear faults is extracted and processed to obtain the attenuation coefficient between insulation resistance and signal transmission loss, and the perturbation coefficient between electromagnetic interference intensity and control command distortion. This process includes the following steps: Extract historical abnormal resistance values ​​from the historical detection data of the switchgear faults, where the insulation resistance of the switchgear circuit is less than the loss resistance threshold. The resistance change amplitude is obtained by subtracting the loss resistance threshold and the historical abnormal resistance value. The historical signal transmission loss values ​​of the switchgear corresponding to the resistance change amplitude were extracted from historical detection data. The attenuation coefficient is obtained by comparing the historical signal transmission loss value with the resistance change amplitude. The electromagnetic interference intensity of the risk points of control command distortion in the switchgear is extracted from historical detection data; Historical control command distortion values ​​of the switchgear affected by electromagnetic interference intensity were extracted from historical detection data. The perturbation coefficient is obtained by comparing the historical control command distortion value with the electromagnetic interference intensity.

4. The switchgear fault detection method of claim 1, wherein, The signal transmission attenuation value affecting the signal transmission loss inside the switchgear under test is obtained based on the attenuation coefficient and the insulation resistance to be measured. The specific steps include: Distinguish the characteristic components in the attenuation coefficient corresponding to different insulation resistance ranges, and determine the characteristic component that matches the range of the insulation resistance under test as the matching attenuation coefficient. By combining the inherent characteristics of the insulating medium inside the switchgear under test, the actual characterization value of the insulation resistance under test is corrected to obtain the corrected insulation resistance value. The basic resistance value is obtained by performing loss correlation transformation on the modified insulation resistance value based on the adaptive resistance attenuation coefficient. The signal transmission attenuation value is obtained by adjusting the basic attenuation value through loss compensation.

5. The switchgear fault detection method of claim 4, wherein, It also includes the following steps: The degree of insulation state deviation is obtained by identifying the trend of the change in the corrected insulation resistance value from the reference state. The impedance change in signal transmission impedance due to the degree of insulation state deviation is determined based on the adaptation impedance coefficient. The impedance change value is compared with the tolerance threshold of the signal transmission path; If the impedance change value does not exceed the tolerance threshold, it is determined that the insulation resistance under test does not have an impedance disturbance effect on the signal transmission path inside the cabinet. If the impedance change exceeds the tolerance threshold, it is determined that the insulation resistance under test has an impedance disturbance effect on the signal transmission path inside the cabinet.

6. The switchgear fault detection method of claim 5, wherein, The first condition influence value is obtained based on the perturbation coefficient, the electromagnetic interference intensity under test, and the signal transmission attenuation value, specifically including the following steps: The mapping relationship between the perturbation coefficient and the control command distortion is defined as the normalized perturbation coefficient; The actual conduction path and range of electromagnetic interference inside the switchgear are determined. Based on the actual conduction path, range, and regular perturbation coefficient, the intensity of electromagnetic interference on the other side is transformed by distortion mapping to obtain the basic interference parameters characterizing the degree of disturbance to control commands. The basic interference parameters and signal transmission attenuation values ​​are coupled and fused to obtain the comprehensive state parameters. The comprehensive state parameters are then modified according to the operating conditions to obtain the first condition influence value.

7. The switchgear fault detection method of claim 1, wherein, Based on the amplitude and direction of the cabinet vibration resonance of the location inside the switchgear to which the electromagnetic interference intensity is to be measured, the influence of vibration resonance on the interference intensity of that location in the switchgear is determined. This involves the following steps: Locate the target location inside the switch cabinet corresponding to the intensity of the electromagnetic interference to be measured, collect the cabinet vibration resonance amplitude corresponding to the target location, and perform amplitude normalization processing on the cabinet vibration resonance amplitude to obtain the standard resonance amplitude. The relative relationship between the resonance direction and the signal transmission direction at the target location is determined, and the guiding effect of the resonance direction on the electromagnetic interference propagation path is judged based on the relative relationship to obtain the resonance guiding characteristics. Using the resonance guiding characteristics as a constraint, and combining the vibration intensity of the standard resonance amplitude, the preliminary parameters of the resonance effect on electromagnetic interference are obtained. By correlating and fusing the preliminary operating parameters with the electromagnetic interference intensity to be measured, the influence value of the interference intensity of this part of the switch cabinet under test due to vibration resonance is obtained.

8. The switchgear fault detection method of claim 7, wherein, The second condition influence value is obtained based on the interference intensity condition influence value, the electromagnetic interference intensity under test, the perturbation coefficient, and the signal transmission attenuation value. This process includes the following steps: Based on the vibration resonance characteristics corresponding to the influence value of the interference intensity, the characteristic parameters of the perturbation coefficient are adjusted to obtain the resonance adaptation perturbation coefficient. The influence value of the interference intensity condition is correlated with the electromagnetic interference intensity to be measured and calibrated to obtain the corrected electromagnetic interference intensity. The modified electromagnetic interference intensity is correlated with the resonant adaptation perturbation coefficient to obtain the resonant adaptation perturbation coefficient and the resonant modified electromagnetic interference intensity. By combining the interference state of the resonance-corrected electromagnetic interference intensity with the characterization of the signal transmission attenuation value, the attenuation value after disturbance correction is obtained. The distortion effect parameter is progressively fused with the disturbance-corrected attenuation value to obtain the second state effect value.

9. A switchgear fault detection method according to claim 1, characterized in that, After processing and analyzing the impact values ​​of the first condition, the second condition, and the initial detection and control performance values ​​of the switchgear under test, the switchgear fault early warning result is output, which specifically includes the following steps: Based on the stable operation performance of the switchgear, the initial detection and control performance values ​​of the switchgear under test are reconstructed to obtain the performance benchmark value. Based on the performance benchmark value, the operational anomaly characteristics represented by the first or second condition influence value are mapped to the performance benchmark system to obtain the fused state parameters. Stable fusion parameters are obtained by stability screening of the fusion state parameters; The results of hazard location analysis are obtained by tracing and locating potential hazards based on stable fusion parameters, determining the location and impact range of the hazards. Based on the hazard location results, the operational risks of the switchgear are assessed to obtain switchgear fault early warning results.

10. A switchgear fault detection system for use in a switchgear fault detection method according to any one of claims 1 to 9, characterized by include: Acquisition module: Acquires the insulation resistance and electromagnetic interference intensity of the switchgear under test; Extraction and processing module: Extracts and processes historical detection data related to switchgear faults to obtain the attenuation coefficient between insulation resistance and signal transmission loss, as well as the perturbation coefficient between electromagnetic interference intensity and control command distortion. First processing module: Obtains the signal transmission attenuation value that affects the signal transmission loss in the switch cabinet under test based on the attenuation coefficient and the insulation resistance to be measured; Second processing module: If the insulation resistance to be measured does not affect the impedance disturbance of the signal transmission path in the cabinet, the first condition influence value is obtained based on the perturbation coefficient, the electromagnetic interference intensity to be measured and the signal transmission attenuation value. The third processing module: If the insulation resistance to be tested causes impedance disturbance to the signal transmission path inside the cabinet, the module determines the interference intensity status of the part of the switch cabinet to be tested affected by vibration resonance based on the cabinet vibration resonance amplitude and resonance direction of the location of the electromagnetic interference intensity to be tested; and obtains the second status influence value based on the interference intensity status influence value, the electromagnetic interference intensity to be tested, the disturbance coefficient and the signal transmission attenuation value. Output module: Processes the first condition influence value, the second condition influence value, and the initial detection and control performance value of the switchgear under test, and outputs the switchgear fault early warning result.

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