System and method for improving stability and reliability of 1000kV line sleeve

Abstract

The invention relates to the field of power systems, in particular to a system and a method for improving the stability and the reliability of a 1000kV line sleeve. The system comprises a bushing structure for reducing virtual connection discharge; the on-line monitoring system is used for monitoring weak discharge of the suspension potential in the casing in real time based on a three-ratio method of gas dissolved in oil; and the maintenance and overhaul strategy is used for carrying out regular insulating oil test, evaluating the health condition of the sleeve and discovering a potential discharge problem on the basis of the online monitoring system by combining power failure overhaul for the running sleeve of the same model, and making a retest and maintenance plan according to a test result. According to the invention, faster feedback and higher monitoring frequency are provided, and intermittent bare metal discharge caused by poor contact is effectively avoided. According to the structure optimization, the insulating property of the sleeve is improved, and the probability of fault occurrence is reduced, so that the service life of the sleeve is prolonged, and the unnecessary maintenance cost and downtime are reduced.

Description

Technical Field

[0001] The present invention relates to the field of power systems, and in particular to a system and method for improving the stability and reliability of a 1000 kV line bushing. Background Art

[0002] In the field of ultra-high voltage power transmission, high-voltage bushings are one of the key electrical equipment, and their stability and reliability are crucial to the safe operation of the entire power system. High-voltage bushings not only need to withstand extremely high working voltages, but also have to ensure good insulation performance to ensure the effective transmission of electricity. Existing high-voltage bushings mostly adopt an oil-paper capacitor structure, which is made of cable paper and aluminum foil electrodes inside, and the outside is insulated in air and oil through a porcelain insulator jacket. The process of making high-voltage bushings usually includes the preparation of internal insulation materials, rolling, vacuum impregnation, assembly and final testing. In this process, the quality of the materials, the tightness of the rolling and the accuracy of the impregnation process need to be strictly controlled to ensure the insulation performance and long-term stability of the bushing.

[0003] In the existing high-voltage bushing design, the commonly used discharge detection methods include oil chromatography analysis, partial discharge detection, and frequency domain dielectric spectrum analysis. These methods can monitor and diagnose the operating status of the bushing to a certain extent, but there are still limitations in the detection of weak discharges of suspended potential. For example, although oil chromatography analysis can infer the discharge situation inside the bushing by detecting the type and content of dissolved gas in the oil, this method usually requires regular sampling and cannot achieve real-time monitoring. In addition, although the partial discharge detection technology has high sensitivity, it is limited by electromagnetic interference in the UHV environment, and its detection results may not be stable enough.

[0004] The existing high-voltage bushings have the following deficiencies in design and operation: limitations of monitoring methods, defects in structural design, and deficiencies in maintenance strategies. These deficiencies may lead to bushing insulation aging and equipment failure, affecting the safe operation of the power system. In solving the above problems, the difficulties faced by R&D personnel mainly include technical complexity, challenges in real-time monitoring, and implementation of structural improvements.

[0005] In response to these challenges, some technologies have attempted to provide solutions. For example, patent CN1 17538691A describes a system and method for partial discharge testing of ultra-high voltage / ultra-high voltage bushings. The system induces partial discharge pulse current signals by applying a power frequency power supply for a preset time, and uses a signal detection unit to detect the amplitude and polarity of these signals to identify partial discharge. However, the system mainly focuses on the testing of partial discharge and does not involve the optimization of bushing structure and the formulation of maintenance and repair strategies.

[0006] In addition, patent CN217485215U proposes a high-voltage bushing direct-insertion 1000KV shunt reactor, which includes a high-voltage bushing, a body, a magnetic pressure plate, a high-voltage outlet device, a coil and an oil tank, wherein the high-voltage outlet device is completely installed in the oil tank and fixed to the body, with one end connected to the coil and the other end connected to the high-voltage bushing. This design simplifies the installation process, strengthens the overall mechanical strength of the reactor, and improves the electrical performance of the reactor. Despite this, the patent does not provide a real-time monitoring solution for the weak discharge of the suspended potential inside the bushing, nor does it involve maintenance and repair strategies based on the monitoring results.

[0007] Therefore, there is an urgent need for a system and method for improving the stability and reliability of 1000kV line bushings. Summary of the invention

[0008] The purpose of the present invention is to provide a system and method for improving the stability and reliability of 1000kV line bushings, so as to solve the problems of bushing insulation aging and equipment failure, lack of stability and reliability caused by limitations of monitoring means, structural design defects and insufficient maintenance strategies in the prior art.

[0009] To achieve the above purpose, the following technical solution is adopted.

[0010] A system for improving the stability and reliability of 1000kV line bushings, characterized in that it comprises:

[0011] Bushing structure for reducing virtual discharge;

[0012] Online monitoring system for real-time monitoring of weak discharge of suspended potential inside casing based on three-ratio method of dissolved gas in oil

[0013] The maintenance and overhaul strategy is used to conduct regular insulating oil tests on the same type of bushings in operation based on the online monitoring system in combination with power outage overhaul, evaluate the health status of the bushings, discover potential discharge problems, and formulate retesting and maintenance plans based on the test results.

[0014] Optionally, the sleeve structure for reducing virtual discharge includes a sleeve, and a clamping nut of the sleeve and a screw have a matching clearance, and a matching tolerance is 6H / 6h.

[0015] Optionally, the bushing structure for reducing virtual discharge includes a bushing, and an insulating fixing ring is arranged between a compression spring bottom plate of the bushing and the conductive tube.

[0016] Optionally, the online monitoring system includes:

[0017] Automated oil sampling device for collecting oil samples from high-voltage bushings for gas content analysis;

[0018] Gas analysis instrument: connected to the automated oil sample collection device to analyze the gas content in the oil sample and obtain gas content data;

[0019] The data processing module is used to receive the gas content data provided by the gas analysis instrument, calculate the fault code according to the three-ratio method, and monitor in real time whether a weak discharge of suspended potential occurs inside the casing; if the fault code indicates an abnormality, an alarm is issued in real time and the abnormal discharge is recorded.

[0020] A method for improving the stability and reliability of a 1000 kV line bushing comprises the following steps:

[0021] Optimize the casing structure, adjust the matching clearance between the casing's compression nut and the screw to a tolerance of 6H / 6h, and set an insulating fixing ring between the casing's compression spring bottom plate and the conductive tube;

[0022] Deploy an online monitoring system to monitor the weak discharge of suspended potential inside the casing in real time based on the three-ratio method of dissolved gas in oil

[0023] Develop maintenance and overhaul strategies. For bushings of the same model in operation, conduct regular insulating oil tests based on the online monitoring system in combination with power outage overhauls to assess the health of the bushings, identify potential discharge problems, and develop retest and maintenance plans based on the test results.

[0024] Optionally, the three-ratio method is used to analyze the gas content in the oil sample, including H2, CO, CO2, and CH4, and the specific steps include:

[0025] S1. Determine the concentration of H2, CO, CO2, and CH4 in the oil sample;

[0026] S2. Calculate gas concentration ratios, including H2 / CO ratio, H2 / CO2 ratio and CO / CO2 ratio;

[0027] S3. According to the obtained gas concentration ratio, determine whether a weak suspended potential discharge occurs inside the casing, wherein:

[0028] If the H2 / CO ratio increases abnormally, it indicates discharge activity;

[0029] If the H2 / CO2 ratio increases abnormally, it indicates that the discharge activity is intensifying;

[0030] If the CO / CO2 ratio decreases abnormally, it indicates a decrease in discharge activity;

[0031] S4. Generate a fault diagnosis report based on the judgment result. If discharge activity is detected, trigger an alarm and record the discharge event.

[0032] Optionally, the maintenance and repair strategy includes:

[0033] S11. Real-time monitoring of the acetylene content and other insulating oil parameters in the bushing, including but not limited to dielectric loss and capacitance, to obtain parameter data;

[0034] S12, analyzing the obtained parameter data to evaluate the health status of the casing;

[0035] S13. Based on the evaluation results, if the single value of acetylene content increases while other indicators are normal, a retest and maintenance plan shall be formulated;

[0036] S14, retest and maintenance plan allows the bushing to continue to operate under the premise of ensuring safety, and plans to retest at the next power outage, including repeating steps S11 and S12;

[0037] S15. Based on the results of the retest and maintenance plan, if the acetylene content continues to increase, perform maintenance or replacement operations.

[0038] Optionally, the following steps are also included:

[0039] The abnormal discharge cause analysis module receives the weak discharge signal of the suspended potential of the online monitoring system, and analyzes the causes of the weak discharge of the suspended potential inside the bushing, including but not limited to aging of the insulation material, defects of the insulation material, cable joint problems, external environmental factors and cable design and manufacturing problems;

[0040] The bushing structure optimization suggestion module provides an optimization plan for reducing virtual discharge and improving the insulation performance of the bushing according to the results of the abnormal discharge cause analysis module.

[0041] Optionally, the specific steps of receiving the weak discharge signal of the suspended potential of the online monitoring system through the abnormal discharge cause analysis module and analyzing the cause of the weak discharge of the suspended potential inside the casing include:

[0042] Receive the weak discharge signal of suspended potential collected by the online monitoring system, including partial discharge signal, temperature change, and pressure state;

[0043] The received discharge signal is filtered and denoised by using mean processing or differential processing;

[0044] Extract key characteristic parameters related to abnormal discharge from the preprocessed signal, including ultrasonic signal response time and optical signal response time;

[0045] Using the extracted key feature parameters, the type and severity of abnormal discharge are determined through pattern recognition algorithms;

[0046] Based on the results of pattern recognition, analyze the possible causes of abnormal discharge, including insulation material aging, insulation material defects, and cable joint problems;

[0047] Output the analysis results to maintenance personnel so that they can take appropriate maintenance measures, including fault location and defect type determination

[0048] Based on the possible causes of abnormal discharge, suggestions for bushing structure optimization are automatically generated, including adding equipotential lines, adding sealing rings, and optimizing the internal butt structure of the bushing with silver plating.

[0049] Optionally, based on the result of the pattern recognition step, the specific steps of analyzing the possible causes of abnormal discharge include:

[0050] receiving the results of the pattern recognition output, including information on the type and severity of the abnormal discharge;

[0051] Compare the key characteristic parameters in the pattern recognition results with the known abnormal discharge cause database to determine the possible cause of the abnormal discharge;

[0052] According to the matching degree between the characteristic parameters and the abnormal discharge causes, a weight is assigned to each possible cause to evaluate the likelihood of various causes;

[0053] According to the results of the weight assignment step, all possible causes are ranked and the most likely cause is identified;

[0054] Verify the most likely causes identified in the prioritization step using expert systems or additional online monitoring data;

[0055] Integrate the verification results in the cause verification step to form the final abnormal discharge cause analysis report;

[0056] Result output step: output the final abnormal discharge cause analysis report to the maintenance personnel so that they can take corresponding maintenance measures;

[0057] Based on the final abnormal discharge cause analysis report, suggestions for casing structure optimization are automatically generated.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The three-ratio monitoring system adopted in the present invention can analyze the discharge situation inside the casing in real time. Compared with the traditional oil chromatography analysis method, it provides faster feedback and higher monitoring frequency, so that potential discharge problems can be discovered and handled, reducing the risk of equipment damage caused by delayed problem discovery.

[0060] By precisely controlling the clearance between the compression nut and the screw and adding an insulating fixing ring, the present invention effectively avoids intermittent bare metal discharge caused by poor contact. This structural optimization improves the insulation performance of the bushing, reduces the probability of failure, and thus extends the service life of the bushing.

[0061] The maintenance strategy proposed by this system allows the bushing to continue to operate when it is in good condition, rather than replacing it immediately, which reduces unnecessary maintenance costs and downtime. At the same time, through regular testing and retesting of the insulating oil, the health of the bushing can be more accurately assessed, ensuring maintenance or replacement at the most appropriate time.

[0062] During the production process, this system strictly controls the matching tolerance of the nut and the screw, and adds an insulating fixing ring between the compression spring base plate and the conductive tube. These improvements help improve the consistency and reliability of the product. The optimized process conditions and production process can ensure quality control at each step, thereby improving the performance of the final product.

[0063] This system helps reduce operating costs by reducing unnecessary maintenance and replacement. At the same time, due to the improved reliability of the bushing, the power outage time and economic losses caused by equipment failure are reduced, thereby improving the economic benefits of the entire power system.

[0064] Through the specific three-ratio method steps, a scientific method is provided to determine whether a weak discharge of suspended potential occurs inside the bushing, which improves the accuracy and response speed of fault diagnosis. The application of the abnormal discharge cause analysis module provides an in-depth understanding of the cause of abnormal discharge, making maintenance measures more targeted and improving the maintenance efficiency and reliability of the bushing.

[0065] The integration of the casing structure optimization suggestion module makes it possible to automatically optimize the casing structure according to the analysis results, further improving the performance and life of the casing. Through detailed abnormal discharge cause analysis steps, a systematic method is provided to identify and solve abnormal discharge problems, enhancing the predictive and preventive maintenance capabilities of the system.

[0066] A detailed analysis step based on the pattern recognition results provides an accurate method to determine the specific cause of abnormal discharge, making maintenance measures more precise and effective.

[0067] Through automatically generated casing structure optimization suggestions, the system can not only diagnose problems but also provide solutions, improving the system's adaptability and the efficiency of maintenance work.

[0068] In summary, the system and method not only improve the monitoring and diagnosis capabilities of high-voltage bushings through the implementation of technical solutions, but also improve the stability and reliability of bushings through the optimization of structural design and maintenance strategies, and ultimately achieve economic benefits. These advantages give the system a significant competitive advantage in the field of ultra-high voltage power transmission and are expected to become a new industry standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1The module diagram of an embodiment of a system for improving the stability and reliability of a 1000 kV line bushing according to the present invention.

[0070] Figure 2 1 is a schematic diagram of a module of another embodiment of a system for improving the stability and reliability of a 1000 kV line bushing according to the present invention. DETAILED DESCRIPTION

[0071] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0072] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit exemplary embodiments according to the present invention.

[0073] Example 1

[0074] like Figure 1 As shown, a system for improving the stability and reliability of 1000kV line bushings is shown. The system comprehensively considers the optimization of bushing structure, the application of online monitoring technology, and the formulation of maintenance and overhaul strategies to ensure the stability and reliability of high-voltage bushings in long-term operation.

[0075] The system includes a bushing structure for reducing virtual discharge, which is specially designed to reduce the potential difference caused by poor contact, thereby reducing virtual discharge events. Specifically, a precisely controlled fit clearance is designed between the bushing's compression nut and the screw, and its fit tolerance is 6H / 6h, ensuring the tightness and uniformity of the connection. In addition, an insulating fixing ring is provided between the bushing's compression spring bottom plate and the conductive tube. The insulating fixing ring is made of a material with high voltage resistance and high insulation performance, such as modified polyester or epoxy resin, which effectively isolates the direct contact between the two, prevents intermittent contact discharge, and improves the insulation performance and reliability of the bushing.

[0076] The system also includes an online monitoring system that monitors the weak discharge of suspended potential inside the casing in real time based on the three-ratio method of dissolved gas in oil. The system includes an automated oil sample collection device that collects oil samples from the casing periodically or continuously for gas content analysis. A gas analyzer is connected to the collection device to analyze the gas content of H2, CO, CO2, CH4, etc. in the oil sample. The data processing module receives the analysis results and calculates the fault code based on the three-ratio method to monitor in real time whether there is weak discharge of suspended potential inside the casing. If the fault code indicates an abnormality, the system will alarm in real time and record the abnormal discharge so that maintenance measures can be taken in time.

[0077] The maintenance and overhaul strategy of this system involves regular insulating oil testing based on the online monitoring system for bushings of the same model in operation, combined with power outage overhaul, to evaluate the health of the bushings. By analyzing the changes in the content of dissolved gas in the oil, potential discharge problems can be discovered. If the acetylene content is found to increase in a single value during the test, but other indicators such as dielectric loss and capacitance are normal, a retest and maintenance plan is formulated. The plan allows the bushing to continue to operate while ensuring safety, and retest at the next power outage, so that further maintenance or replacement can be determined based on the retest results.

[0078] Through the above implementation, the system can significantly improve the stability and reliability of 1000kV line bushings, reduce equipment failures caused by virtual discharge, reduce maintenance costs, and improve the safety and economic benefits of the power system. The design and implementation of the system takes into account various factors in actual operation and provides a practical solution to ensure the long-term stable operation of high-voltage bushings in high-voltage transmission lines.

[0079] As a specific example of the above example, an online monitoring system, which is composed of an automated oil sample collection device, a gas analysis instrument and a data processing module, is used to monitor the weak discharge of the suspended potential inside the casing in real time.

[0080] Automatic oil sampling device: This device is designed to automatically collect oil samples from high-voltage bushings for subsequent gas content analysis. The device ensures that the oil sample collection is both safe and efficient, avoiding the errors and contamination that may be caused by manual collection.

[0081] Gas analysis instrument: connected to the automated oil sample collection device, the instrument uses a special composite chromatographic column to improve the separation of gas components. At the same time, it uses an imported special detector to improve the detection sensitivity of hydrocarbon gases. The gas analysis instrument can analyze the gas content of H2, CO, CO2, CH4 and other gases in the oil sample and obtain accurate gas content data.

[0082] The data processing module receives the gas content data provided by the gas analyzer and calculates the fault code according to the three-ratio method. The three-ratio method is a method for diagnosing the internal discharge of electrical equipment by analyzing the ratio of dissolved gas in oil. The data processing module is built into the online monitoring terminal. It is a theoretical analysis algorithm that meets the actual on-site environment requirements by training the feature extraction algorithm, optimizing parameters and verifying performance based on a large amount of original waveform data of the casing under actual operating conditions. The module can monitor in real time whether there is a weak discharge of suspended potential inside the casing. If the fault code indicates an abnormality, the system will alarm in real time and record the abnormal discharge.

[0083] Technical parameters: The system can monitor seven gas components including H2, CO, CO2, CH4, C2H4, C2H2, C2H6, H2O (optional), as well as trace water, relative growth rate and absolute growth rate; trace water in oil monitoring is optional. The system's minimum detection cycle is 40-60 minutes, which can be set by the user, and the default is 24 hours.

[0084] Stability and anti-interference performance: The stability of the system (measurement deviation) under the same test conditions, the deviation of the monitoring results of the same oil sample does not exceed ± 5% (medium concentration). At the same time, the system has high anti-interference performance, and the electromagnetic compatibility meets the GB / T17626 and IEC61000 standards.

[0085] Through the above implementation, the system can realize real-time monitoring of 1000kV line bushings, discover potential discharge problems, and thus improve the stability and reliability of bushings. The implementation of the system takes into account various factors in actual operation and provides a practical solution to ensure the long-term stable operation of high-voltage bushings in high-voltage transmission lines.

[0086] Example 2

[0087] The online monitoring system can monitor the operation status of the bushing in real time without power failure, and specifically includes a partial discharge monitoring module, a temperature monitoring module, and a pressure monitoring module. The monitoring results of these modules are transmitted to the data processing module in real time for comprehensive evaluation of the operation status of the bushing.

[0088] The partial discharge monitoring module uses ultra-high frequency (UHF) sensors to monitor the partial discharge of bushings. UHF sensors are divided into two types: internal and external. They can obtain ultra-high frequency signals inside the GIS switch or bus position, upload them to the partial discharge monitoring IED, and analyze them by the host computer expert analysis software to give a comprehensive judgment result of the partial discharge data.

[0089] The temperature monitoring module uses the digital temperature sensor DS18B20 from DALLAS for temperature measurement. DS18B20 is the world's first temperature sensor that supports the "one-wire bus" interface, which can provide accurate temperature readings and has strong anti-interference and error correction capabilities. The temperature measurement result is directly output as a digital quantity, with a single bus serial transmission mode, and can also transmit CRC check codes to ensure the accuracy of data collection.

[0090] The pressure monitoring module uses the Fluke 750P series pressure module for pressure measurement, which can quickly and easily measure pressure and display pressure in up to 11 different engineering units. Pressure readings can be date / time stamped and stored electronically for later retrieval.

[0091] The data processing module receives data from the partial discharge monitoring module, temperature monitoring module and pressure monitoring module, and is built into the online monitoring terminal based on a high-precision analysis algorithm for bushing insulation state parameters based on time-frequency domain feature fusion. This algorithm solves the phase shift problem caused by DC voltage, harmonic interference, spectrum leakage and frequency fluctuation, and greatly improves the accuracy of online monitoring of bushing dielectric loss factor, full current, capacitance and partial discharge characteristics.

[0092] Example 3

[0093] like Figure 2 As shown, a system for improving the stability and reliability of 1000kV line bushings also includes an abnormal discharge cause analysis module and a bushing structure optimization suggestion module, which are used to monitor and analyze the weak discharge of the suspended potential inside the bushing in real time, and provide a bushing structure optimization plan based on the analysis results.

[0094] The abnormal discharge cause analysis module receives the weak discharge signal of suspended potential collected by the online monitoring system, including key parameter data such as partial discharge signal, temperature change, and pressure status.

[0095] The received discharge signal is filtered and denoised by using mean processing or differential processing to improve the signal quality.

[0096] Key characteristic parameters related to abnormal discharge, such as ultrasonic signal response time, optical signal response time, etc., are extracted from the preprocessed signals.

[0097] The extracted key feature parameters are used to determine the type and severity of abnormal discharge through pattern recognition algorithm.

[0098] Pattern recognition algorithm application:

[0099] Using the extracted key feature parameters, a pattern recognition algorithm is applied to determine the type and severity of abnormal discharge. For example, algorithms such as support vector machine (SVM) or K nearest neighbor algorithm (KNN) can be used for classification.

[0100] Taking SVM as an example, by mapping the data set into a high-dimensional space, an optimal hyperplane is found to segment the data, thereby identifying different discharge patterns.

[0101] Based on the results of pattern recognition, the possible causes of abnormal discharge are analyzed, including insulation material aging, insulation material defects, cable joint problems, external environmental factors and cable design and manufacturing problems.

[0102] Bushing structure optimization suggestion module: Based on the results of the abnormal discharge cause analysis module, it provides an optimization plan for the bushing structure to reduce virtual discharge and improve the insulation performance of the bushing.

[0103] Optimization plans may include adding equipotential lines, adding sealing rings, optimizing the internal docking structure of the silver-plated sleeve, and other structural adjustments to reduce the occurrence of abnormal discharge in the future.

[0104] The module also takes into account the long-term operational reliability of the casing and significantly improves the hardware performance of the perception system by simulating the measurement accuracy and operational reliability under operating conditions.

[0105] Example 4

[0106] A method for improving the stability and reliability of 1000 kV line bushings, comprising the following steps:

[0107] Optimize the casing structure: adjust the fitting clearance between the casing's compression nut and the screw to a tolerance of 6H / 6h to ensure the tightness and uniformity of the connection and reduce the phenomenon of virtual connection discharge caused by poor contact.

[0108] An insulating fixing ring is arranged between the compression spring bottom plate of the bushing and the conductive tube. The insulating fixing ring is made of a high insulating material, such as modified polyester or epoxy resin, which effectively isolates the direct contact between the two, prevents intermittent bare metal discharge, and improves the insulation performance and reliability of the bushing.

[0109] Deploy an online monitoring system: Deploy an online monitoring system that monitors the weak discharge of suspended potential inside the casing in real time based on the three-ratio method of dissolved gas in oil.

[0110] The automated oil sampling device collects oil samples from the casing periodically or continuously for gas content analysis.

[0111] The gas analysis instrument is connected to the automated oil sample collection device to analyze the gas content of H2, CO, CO2, CH4, etc. in the oil sample to obtain gas content data.

[0112] The data processing module receives the gas content data provided by the gas analyzer, calculates the fault code according to the three-ratio method, and monitors in real time whether there is a weak discharge of suspended potential inside the casing. If the fault code indicates an abnormality, the system will alarm in real time and record the abnormal discharge.

[0113] Formulate maintenance and overhaul strategies: For bushings of the same model in operation, conduct regular insulating oil tests based on the online monitoring system in combination with power outage overhaul to assess the health of the bushings.

[0114] By analyzing the changes in the content of dissolved gas in the oil, potential discharge problems can be discovered.

[0115] Based on the evaluation results, if the acetylene content value increases while other indicators are normal, a retest and maintenance plan is formulated to allow the casing to continue to operate while ensuring safety, and a retest is planned at the next power outage, including repeated oil sampling and parameter measurement.

[0116] Based on the results of the retest and maintenance plan, if the acetylene content continues to increase, maintenance or replacement operations are performed to ensure the stability and reliability of the casing.

[0117] This method can significantly improve the stability and reliability of 1000kV line bushings, reduce equipment failures caused by virtual discharge, reduce maintenance costs, and improve the safety and economic benefits of the power system. The design and implementation of this method take into account various factors in actual operation and provide a practical solution to ensure the long-term stable operation of high-voltage bushings in high-voltage transmission lines.

[0118] As a specific example of the above example, the three-ratio method is used to analyze the gas content in the oil sample, including hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2) and methane (CH4). The monitoring and diagnosis of the weak discharge of the suspended potential inside the casing is achieved through the following steps:

[0119] Determine the gas concentration in the oil sample:

[0120] First, oil samples are collected from the high-voltage bushing using an automated oil sampling device.

[0121] The collected oil samples are then analyzed using a gas analyzer to determine the concentrations of H2, CO, CO2, and CH4. This step is accomplished by performing a chromatographic analysis on the oil samples, which can accurately measure and record the concentrations of these gases.

[0122] Calculate the gas concentration ratio:

[0123] Based on the measured gas concentrations, the H2 / CO ratio, H2 / CO2 ratio and CO / CO2 ratio are calculated. These ratios are obtained by calculation algorithms in the data processing module, which process the data from the gas analysis instrument and calculate the required ratios.

[0124] Determine whether weak discharge of suspended potential occurs inside the bushing:

[0125] If the H2 / CO ratio is abnormally high, this may indicate discharge activity inside the casing.

[0126] If the H2 / CO2 ratio increases abnormally, this may indicate an increase in discharge activity.

[0127] If the CO / CO2 ratio is abnormally low, this may indicate a decrease in discharge activity.

[0128] These judgments are based on industry standards and historical data, and these standards and thresholds are built into the data processing module to enable accurate judgments.

[0129] Generate a troubleshooting report:

[0130] Based on the above judgment results, the data processing module will generate a fault diagnosis report. If a discharge activity is detected, the system will trigger an alarm and record the discharge event, including detailed information such as the time, location and intensity of the discharge.

[0131] The fault diagnosis report will be provided to the maintenance personnel so that they can take necessary maintenance measures in time, such as further inspection, repair or replacement of parts.

[0132] As a specific example, the maintenance and overhaul strategy aims to evaluate the health of the bushing by real-time monitoring of the acetylene content and other insulating oil parameters in the bushing, and formulate corresponding retesting and maintenance plans based on the evaluation results. The following are the specific steps:

[0133] Real-time monitoring of acetylene content and other insulating oil parameters in the bushing:

[0134] Use an automated oil sampling device to regularly collect oil samples from the high-voltage bushing to measure the acetylene content and other insulating oil parameters (including but not limited to dielectric loss and capacitance).

[0135] The acetylene content in the oil sample is quantitatively analyzed using a high-precision gas analyzer, while the dielectric loss tester and capacitance tester are used to measure the dielectric loss and capacitance in the oil.

[0136] Analyze the obtained parameter data to evaluate the health of the casing:

[0137] The measured acetylene content and other parameter data are input into the data processing module, which uses advanced data analysis algorithms to process and analyze the data.

[0138] Based on historical data and preset thresholds, the health of the bushing is assessed to determine if there is a potential discharge problem or other failure risk.

[0139] Develop a retest and maintenance plan:

[0140] If the acetylene content increases but other indicators are normal, it indicates that there may be a partial discharge problem in the bushing, but it has not yet affected the overall insulation performance. At this time, a retest and maintenance plan is formulated, which includes more detailed inspections and necessary maintenance work during the next scheduled power outage window.

[0141] The retest plan includes repeating the oil sample collection and parameter measurement in step 1, as well as a comprehensive inspection of the casing, such as ultrasonic testing, X-ray testing, etc.

[0142] Execute retest and maintenance plan:

[0143] Under the premise of ensuring safety, the bushing is allowed to continue to operate until the next power outage window. During this period, the acetylene content and other parameters of the bushing are continuously monitored in real time to ensure that the bushing status is stable.

[0144] During the outage window, a retest plan was implemented, including repeated oil sampling and parameter measurements, and a comprehensive inspection of the casing.

[0145] Perform maintenance or replacement operations based on the retest results:

[0146] If the retest results show a continued increase in acetylene levels, this indicates that the bushing's partial discharge problem may be worsening and maintenance or replacement may be necessary.

[0147] Maintenance operations may include cleaning the bushing, replacing damaged parts, or re-insulating the bushing. If maintenance does not solve the problem, the entire bushing may need to be replaced.

[0148] As a specific example of the above, the abnormal discharge cause analysis module is designed to accurately identify and analyze the causes of weak discharge of suspended potential inside the casing and provide structural optimization suggestions based on this.

[0149] The abnormal discharge cause analysis module first receives the weak discharge signal of suspended potential from the online monitoring system. These signals include partial discharge signals, real-time temperature changes and pressure status, which are key parameters for evaluating the health status of the casing.

[0150] The received discharge signal is filtered and denoised by averaging or differencing. Averaging reduces random noise by taking the average of multiple samples, while differencing removes DC offset and reduces noise by calculating the difference between consecutive samples.

[0151] Key characteristic parameters are extracted from the preprocessed signals, which are closely related to abnormal discharge, such as ultrasonic signal response time and optical signal response time. These characteristic parameters are important basis for identifying the type and severity of discharge.

[0152] Using the extracted key feature parameters, the type and severity of abnormal discharge are determined through pattern recognition algorithms. Pattern recognition algorithms may include machine learning techniques such as support vector machines (SVMs), neural networks, or decision trees, which can be trained based on historical data and known discharge patterns to identify new discharge events.

[0153] Based on the results of pattern recognition, the possible causes of abnormal discharge are analyzed, which may include insulation material aging, insulation material defects, or cable joint problems. The analysis is based on comparing the actual characteristic parameters with the expected parameters under normal operating conditions and identifying specific patterns that deviate from the normal range.

[0154] The analysis results are output to maintenance personnel so that appropriate maintenance measures can be taken. These measures may include fault location and determination of defect type, allowing targeted repair or component replacement.

[0155] Based on the possible causes of abnormal discharge, the system automatically generates suggestions for optimizing the casing structure. These suggestions may include adding equipotential lines to reduce potential differences, adding sealing rings to improve waterproof performance, or silver-plating the internal butt joint structure of the casing to enhance conductivity and corrosion resistance.

[0156] As a specific example of the above example, according to the result of the pattern recognition step, the specific step of analyzing the possible cause of abnormal discharge includes that the system first receives the output result from the pattern recognition algorithm, which includes the type and severity information of the abnormal discharge. This information is obtained by analyzing the gas content in the oil sample and the online monitoring data.

[0157] The system compares the key characteristic parameters in the pattern recognition results with the known abnormal discharge cause database. The database contains historical data and expert knowledge, which is used to match the current characteristic parameters with historical cases to determine the possible causes of abnormal discharge.

[0158] Based on the degree of match between the characteristic parameters and the cause of abnormal discharge, the system assigns weights to each possible cause and evaluates the likelihood of each cause. This step uses statistical algorithms or machine learning models, such as Bayesian classifiers, to quantify the probability of each cause.

[0159] Based on the results of the weighting step, the system ranks all possible causes and identifies the most likely cause. This step ensures that maintenance personnel can prioritize the most likely cause.

[0160] The system verifies the most likely causes identified in the prioritization step through an expert system or additional online monitoring data. The expert system may include a rule base and an inference engine to further verify the possible causes based on expert experience and real-time data.

[0161] The system integrates the verification results in the cause verification step to form a final abnormal discharge cause analysis report. The report details the cause, severity and recommended maintenance measures of the abnormal discharge.

[0162] The system outputs the final abnormal discharge cause analysis report to the maintenance personnel so that they can take appropriate maintenance measures. The report is displayed through the user interface and can also be pushed via email or mobile application.

[0163] Based on the final abnormal discharge cause analysis report, the system automatically generates suggestions for bushing structure optimization. These suggestions may include improving the bushing insulation material, adjusting the design to reduce mechanical stress, or enhancing the bushing sealing performance.

[0164] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

Claims

1. A system for improving the stability and reliability of 1000kV line bushings, characterized in that: include, Bushing structure for reducing virtual discharge; The online monitoring system is used to monitor the weak discharge maintenance and repair strategy of the suspended potential inside the bushing in real time based on the three-ratio method of dissolved gas in oil. For bushings of the same model in operation, regular insulating oil tests are performed based on the online monitoring system in combination with power outage maintenance to evaluate the health status of the bushing, discover potential discharge problems, and formulate retest and maintenance plans based on the test results.

2. A system for improving the stability and reliability of 1000kV line bushing according to claim 1, characterized in that: The bushing structure for reducing virtual discharge comprises a bushing, and a clamping nut of the bushing and a screw rod have a matching clearance, and a matching tolerance is 6H / 6h.

3. A system for improving the stability and reliability of 1000kV line bushing according to claim 1, characterized in that: The bushing structure for reducing virtual discharge comprises a bushing, and an insulating fixing ring is arranged between a compression spring bottom plate of the bushing and a conductive tube.

4. A system for improving the stability and reliability of 1000kV line bushing according to claim 1, characterized in that: The online monitoring system comprises: Automated oil sampling device for collecting oil samples from high-voltage bushings for gas content analysis; Gas analysis instrument: connected to the automated oil sample collection device to analyze the gas content in the oil sample and obtain gas content data; The data processing module is used to receive the gas content data provided by the gas analysis instrument, calculate the fault code according to the three-ratio method, and monitor in real time whether a weak discharge of suspended potential occurs inside the casing; if the fault code indicates an abnormality, an alarm is issued in real time and the abnormal discharge is recorded.

5. A method for improving the stability and reliability of a 1000 kV line bushing, based on a system for improving the stability and reliability of a 1000 kV line bushing according to any one of claims 1 to 4, characterized in that: The following steps are involved: Optimize the casing structure, adjust the matching clearance between the casing's compression nut and the screw to a tolerance of 6H / 6h, and set an insulating fixing ring between the casing's compression spring bottom plate and the conductive tube; Deploy an online monitoring system, and formulate maintenance and overhaul strategies by real-time monitoring of the weak discharge of suspended potential inside the bushing based on the three-ratio method of dissolved gas in oil. For bushings of the same model in operation, conduct regular insulating oil tests based on the online monitoring system in combination with power outage overhaul to evaluate the health status of the bushing, identify potential discharge problems, and formulate retest and maintenance plans based on the test results.

6. A method for improving the stability and reliability of 1000 kV line bushing according to claim 5, characterized in that: The three-ratio method is used to analyze the gas content in the oil sample, including H2, CO, CO2, and CH4. The specific steps include S1, determining the concentration of H2, CO, CO2, and CH4 in the oil sample; S2. Calculate gas concentration ratios, including H2 / CO ratio, H2 / CO2 ratio and CO / CO2 ratio; S3. According to the obtained gas concentration ratio, determine whether a weak suspended potential discharge occurs inside the casing, wherein: If the H2 / CO ratio increases abnormally, it indicates discharge activity; If the H2 / CO2 ratio increases abnormally, it indicates that the discharge activity is intensifying; If the CO / CO2 ratio decreases abnormally, it indicates a decrease in discharge activity; S4. Generate a fault diagnosis report based on the judgment result. If discharge activity is detected, trigger an alarm and record the discharge event.

7. A method for improving the stability and reliability of 1000 kV line bushing according to claim 5, characterized in that: The maintenance and overhaul strategy includes: S11. Real-time monitoring of the acetylene content and other insulating oil parameters in the bushing, including but not limited to dielectric loss and capacitance, to obtain parameter data; S12, analyzing the obtained parameter data to evaluate the health status of the casing; S13. Based on the evaluation results, if the single value of acetylene content increases while other indicators are normal, a retest and maintenance plan shall be formulated; S14, retest and maintenance plan allows the bushing to continue to operate under the premise of ensuring safety, and plans to retest at the next power outage, including repeating steps S11 and S12; S15. Based on the results of the retest and maintenance plan, if the acetylene content continues to increase, perform maintenance or replacement operations.

8. A method for improving the stability and reliability of 1000 kV line bushing according to claim 5, characterized in that: The following steps are also included: The abnormal discharge cause analysis module receives the weak discharge signal of the suspended potential of the online monitoring system, and analyzes the causes of the weak discharge of the suspended potential inside the casing, including but not limited to aging of the insulation material, defects of the insulation material, cable joint problems, external environmental factors and cable design and manufacturing problems; The bushing structure optimization suggestion module provides an optimization plan for reducing virtual discharge and improving the insulation performance of the bushing according to the results of the abnormal discharge cause analysis module.

9. A method for improving the stability and reliability of 1000 kV line bushing according to claim 8, characterized in that: The specific steps of receiving the weak discharge signal of the suspension potential of the online monitoring system through the abnormal discharge cause analysis module and analyzing the cause of the weak discharge of the suspension potential inside the casing include: Receive the weak discharge signal of suspended potential collected by the online monitoring system, including partial discharge signal, temperature change, and pressure state; The received discharge signal is filtered and denoised by using mean processing or differential processing; Extract key characteristic parameters related to abnormal discharge from the preprocessed signal, including ultrasonic signal response time and optical signal response time; Using the extracted key feature parameters, the type and severity of abnormal discharge are determined through pattern recognition algorithms; Based on the results of pattern recognition, analyze the possible causes of abnormal discharge, including insulation material aging, insulation material defects, and cable joint problems; The analysis results are output to the maintenance personnel so that corresponding maintenance measures can be taken, including fault location and defect type determination. Based on the possible causes of abnormal discharge, suggestions for bushing structure optimization are automatically generated, including adding equipotential lines, adding sealing rings, and silver-plated bushing internal docking structure optimization solutions.

10. A method for improving the stability and reliability of 1000 kV line bushing according to claim 9, characterized in that: Based on the results of the pattern recognition step, the specific steps of analyzing the possible causes of abnormal discharge include: receiving the results of the pattern recognition output, including information on the type and severity of the abnormal discharge; Compare the key characteristic parameters in the pattern recognition results with the known abnormal discharge cause database to determine the possible cause of the abnormal discharge; According to the matching degree between the characteristic parameters and the abnormal discharge causes, a weight is assigned to each possible cause to evaluate the likelihood of various causes; According to the results of the weight assignment step, all possible causes are ranked and the most likely cause is identified; Verify the most likely causes identified in the prioritization step using expert systems or additional online monitoring data; Integrate the verification results in the cause verification step to form the final abnormal discharge cause analysis report; Result output step: output the final abnormal discharge cause analysis report to the maintenance personnel so that they can take corresponding maintenance measures; Based on the final abnormal discharge cause analysis report, suggestions for casing structure optimization are automatically generated.

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