A multi-component maintenance method for high-voltage circuit breakers based on fault correlation

Abstract

The invention discloses a method for repairing multiple components of a high-voltage circuit breaker based on fault correlation, and relates to the technical field of high-voltage circuit breaker maintenance. The method comprises the steps of subsystem repair and multiple component combination repair, wherein the subsystem repair step comprises, according to the confidence of each single component from large to small, performing maintenance and inspection of a crank arm, a base, a buffer and a rotating shaft in sequence when repairing a mechanical system fault; first maintaining a conductor loop and then performing contact maintenance when repairing an electrical system fault; and performing maintenance in the order of SF6 gas and insulating parts when repairing an insulation system fault. The multiple component combination repair step comprises, based on the correlation between component faults, forming two maintenance combinations, the first combination being a rotating shaft, a crank arm and a conductor loop, and the second combination being a buffer, a contact and SF6 gas; when a component in the combination fails, other components are simultaneously inspected and maintained; and the maintenance time of the high-voltage circuit breaker is reduced through the steps of subsystem repair and multiple component combination repair.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage circuit breaker maintenance, and in particular to a fault-related based high-voltage circuit breaker multi-component maintenance method. Background Art

[0002] High-voltage circuit breakers have a complex structure and consist of many types of components in large quantities. As the service life increases, their operating reliability will continue to deteriorate due to mechanical wear, reduced insulation performance, external force damage, SF6 gas failure and other factors. In order to prevent sudden failures of high-voltage circuit breakers, it is extremely important to accurately assess their status and perform appropriate maintenance and repairs. According to relevant statistics, maintenance costs and failure costs account for more than 50% of the total cost of high-voltage circuit breakers.

[0003] Research on Circuit Breaker Fault Diagnosis Method Based on Principal Component Analysis-Support Vector Machine Optimization Model, by Fan Hao, Li Xingwen, Su Haibo, etc. Research on Mechanical Fault Diagnosis Technology of High-voltage Circuit Breakers Based on Kernel Principal Component Analysis-SoftMax, by Wang Yuhao, Wu Jianwen, Ma Suliang, etc. Transactions of China Electrotechnical Society. Fault Diagnosis of High-voltage Circuit Breakers Based on Multi-feature Selection Method, by Li Bangyan, Qi Weiqiang, Yang Zhaojing, etc. Faults of high-voltage circuit breakers are diagnosed through multi-feature selection, support vector machine, principal component analysis, etc.

[0004] "A method for evaluating the state of SF6 high-voltage circuit breakers based on cloud model", by Liu Jinjie, Ye Bo, Luo Zanchen, etc. "A method for evaluating the state of high-voltage circuit breakers based on matter-element extension theory", by Chang Yidong, Zhang Kaixuan, Jin Xiao. "Comprehensive evaluation of the state of SF6 high-voltage circuit breakers based on association rules and variable weight coefficients", by Huang Xuyong, Sun Peng, Geng Sujie, etc. Evaluate the operating state of high-voltage circuit breakers using cloud models, matter-element extension theory and association rules.

[0005] "Life Cycle Cost Assessment of High-Voltage Circuit Breakers Based on System Dynamics", by Tusongjiang Kari, Lu Haotan, Gao Wensheng, etc. A model reflecting the life cycle cost of high-voltage circuit breakers was established based on system dynamics.

[0006] "Failure Mechanism Analysis and Life Assessment of High Voltage Circuit Breakers", by Ye Yuyuan, Southeast University. The life of high voltage circuit breakers is predicted using health index and hierarchical analysis.

[0007] The above technical solutions have conducted in-depth research on the fault diagnosis method, status evaluation and remaining life of high-voltage circuit breakers, but have not involved preventive maintenance and fault repair strategies. Summary of the invention

[0008] The present invention provides a multi-component maintenance method for a high-voltage circuit breaker based on fault correlation, which solves the technical problem of low maintenance efficiency caused by the lack of preventive maintenance and fault maintenance methods.

[0009] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0010] A method for multi-component maintenance of a high-voltage circuit breaker based on fault correlation includes the steps of subsystem maintenance and multi-component combination maintenance. The subsystem maintenance step includes, according to the confidence of each single component from large to small, when repairing a mechanical system fault, performing maintenance and inspection on a crank arm, a base, a buffer and a rotating shaft in sequence; when repairing an electrical system fault, first maintaining a conductor loop and then performing contact maintenance; when repairing an insulation system fault, the maintenance sequence is based on SF6 gas and insulating parts; the multi-component combination maintenance step includes, based on the correlation between component faults, forming two maintenance combinations with the goal of reducing the maintenance time of the high-voltage circuit breaker and reducing the overall disassembly cost of the equipment, the first combination is a rotating shaft, a crank arm and a conductor loop, and the second combination is a buffer, a contact and SF6 gas; when a component in the combination fails, other components are simultaneously inspected and maintained.

[0011] A further technical solution is that it also includes an analysis step for obtaining the subsystem maintenance and multi-component combination maintenance steps, the analysis step includes a fault sample acquisition step, the fault sample acquisition step includes obtaining a single component fault statistics table by statistically analyzing single component faults, and single component faults include loose base, stuck shaft, buffer performance degradation, insufficient arm lubrication, excessive conductor loop resistance, contact wear, SF6 gas failure and partial discharge of insulating parts; and obtaining a subsystem fault statistics table by statistically analyzing subsystem faults, and subsystem faults include mechanical system faults, electrical system faults and insulation system faults.

[0012] A further technical solution is that the step of obtaining fault samples also includes that single component failures coexist and there is fault correlation, and the failures of loose base, degraded buffer performance, stuck shaft, excessive conductor loop resistance and insufficient arm lubrication account for a relatively high proportion; among subsystem failures, mechanical system failures account for a relatively high proportion.

[0013] A further technical solution is that: the analysis step further includes a single component failure risk analysis step within the subsystem, and the single component failure risk analysis step within the subsystem includes the following steps:

[0014] The association rules are applied to the risk analysis of single component failure in the high-voltage circuit breaker subsystem. By calculating the support and confidence of single component failure, the influence of single component on subsystem failure is quantitatively described.

[0015] Association rules quantitatively describe the correlation between different items in the same event by mining the hidden associations between them. The basic definition of association rules is as follows:

[0016] The transaction database D is a collection of subset transactions T, D = {T1, T2..., T n}, the number of subset transactions is n; subset transaction T = {i1,i2,...,i m}, i is called an item, the number of items is m; A and B are subsets of i, called item set A and item set B;

[0017] The support of item set A is the number of transactions in D that contain item set A, denoted as σ(A);

[0018]

[0019] In formula (1), σ(A) is the support of item set A, D is the transaction database, and T is the subset transaction of transaction database D;

[0020] If the item set And A∩B=Φ, A is the premise of association rule A→B, B is the conclusion of association rule A→B, and the support of A→B is the ratio of A∪B in D, which is recorded as:

[0021] Sup(A→B)=P(A∪B) (2)

[0022] In formula (2), Sup(A→B) is the support of A→B;

[0023] The conditional probability P(B|A) in database D represents the confidence of association rule A→B, which is denoted as

[0024]

[0025] In formula (3), C(A→B) is the confidence of association rule A→B.

[0026] A further technical solution is that the single component failure risk analysis step in the subsystem further includes the following steps:

[0027] Define as follows:

[0028] 1) D = {high-voltage circuit breaker failure caused by subsystem failure}, where D is a transaction database formed by the high-voltage circuit breaker failure caused by the subsystem failure;

[0029] 2) B = {subsystem failure caused by single component failure};

[0030] 3) A i = {high voltage circuit breaker failure caused by single component failure}, A i represents the i-th single component in the subsystem;

[0031] Use equations (4) and (5) to calculate association rule A respectively i →B's support and confidence;

[0032]

[0033] In formula (4), Sup(A i →B) is association rule A i →B's support;

[0034]

[0035] In formula (5), C(A i →B) is association rule A i →B's confidence level.

[0036] A further technical solution is that the single component failure risk analysis step within the subsystem also includes the following steps: when repairing the mechanical system, electrical system and insulation system of the high-voltage circuit breaker, each single component should be differentially maintained from high to low confidence level to achieve a balance between maintenance effect and maintenance efficiency.

[0037] A further technical solution is that: the analysis step further includes a multi-component fault correlation analysis step, and the multi-component fault correlation analysis step includes:

[0038] High-voltage circuit breakers are complex systems composed of multiple interconnected and interacting components. When making maintenance decisions, it is necessary to consider the propagation and coupling between the faults of each component.

[0039] The chi-square test is a widely used nonparametric hypothesis testing method. It analyzes the correlation between two variables by comparing the degree of deviation between the theoretical frequency and the actual frequency. The calculation formula is shown in formula (6);

[0040]

[0041] In formula (6), χ 2 is the chi-square test statistic, χ 2 The larger the value, the closer f0 is to f e The larger the correlation, the greater the actual frequency f0 represents. e represents the theoretical frequency;

[0042] Odds ratio (OR), also known as odds ratio, is used to describe the relative risk of exposure to a factor to that of not being exposed to the factor. Define the failure rate of a single component in a subsystem of a high-voltage circuit breaker as a, and the non-failure rate as b, and the failure rate of a single component in a control subsystem as c, and the non-failure rate as d. The formula for calculating the odds ratio is shown in formula (7);

[0043] OR=(a / b) / (c / d) (7)

[0044] In formula (7), OR is the risk of a factor, which is the relative risk of not being exposed to the factor. The failure rate of a single component in a subsystem of a high-voltage circuit breaker is a, and the non-occurrence rate is b. The failure rate of a single component in a control subsystem is c, and the non-occurrence rate is d.

[0045] SPSS24.0 data analysis software was used to perform chi-square test and odds ratio calculation to analyze whether the correlation between single component failures of high-voltage circuit breakers was significant; in the chi-square test, p < 0.05 and OR > 1 indicated that there was a significant correlation between single component failures.

[0046] A further technical solution is that: the multi-component fault correlation analysis step further includes the following steps:

[0047] There is a significant correlation between the shaft jamming, insufficient arm lubrication and excessive conductor loop resistance faults. There is a significant correlation between the buffer performance degradation, contact wear and SF6 gas failure faults. There are two propagation paths between component faults.

[0048] In path 1, through the ratio of shaft jamming, insufficient lubrication of the crank arm and excessive conductor loop resistance, it is known that shaft jamming and insufficient lubrication of the crank arm will increase the possibility of excessive conductor loop resistance;

[0049] In path two, the degradation of buffer performance will increase the possibility of contact wear, and contact wear will increase the possibility of SF6 gas failure.

[0050] A further technical solution is: it also includes a combined maintenance effect evaluation step, which includes the following steps: reliability, safety, economy and integrity in the maintenance optimization effect are used as evaluation indicators of the combined maintenance effect of the high-voltage circuit breaker;

[0051] The strength of the evaluation index of the multi-component combination maintenance of high-voltage circuit breakers is divided into four levels: none, small, medium, and large. The fuzzy statistical method and scale scoring method are used to quantify the specific indicators within the range of 0 to 3, and the matrix expression is shown in formula (8);

[0052]

[0053] In formula (8), U is the strength matrix of the evaluation index of the combined maintenance of high-voltage circuit breakers, and u1~u4 represent reliability, safety, economy and integrity, respectively.

[0054] A further technical solution is that: the combined maintenance effect evaluation step further includes the following steps: based on the combined maintenance effect evaluation of the product-sum formula, the interaction matrix expression of the four evaluation indicators is shown in formula (9);

[0055]

[0056] In formula (9), F is the interaction matrix of the mutual influence between the evaluation indicators of the maintenance effect of multiple components of high-voltage circuit breakers, f ij is the interaction value of indicator i on indicator j; in order to be consistent with the quantitative range of indicator strength, 0 to 3 points are used to represent no interaction, weak interaction, moderate interaction and strong interaction;

[0057] Define the comprehensive matrix M for combined maintenance effect evaluation, as shown in formula (10); the elements in M ​​reflect the comprehensive characteristics of the maintenance evaluation index, examine the maintenance association between component combinations, and each evaluation index value and the interaction between the indicators are quantitatively expressed by the matrix M;

[0058]

[0059] In formula (10), M is the comprehensive matrix for combined maintenance effect evaluation;

[0060] The product-sum formula is defined as follows: n-order matrix A = (a ij ) n×n The product and sum of is shown in formula (11);

[0061]

[0062] In formula (11), per(A) is a comprehensive evaluation index of reliability, safety, economy and integrity, σ(i) is the element at the i-th position of σ, S n It is the set of all possible arrangements; the product-sum formula is applied to the evaluation of the combined maintenance effect of multiple components of high-voltage circuit breakers. The larger the comprehensive index, the better the combined maintenance effect.

[0063] The beneficial effects of adopting the above technical solution are:

[0064] A method for repairing multiple components of a high-voltage circuit breaker based on fault correlation includes the steps of subsystem repair and multi-component combination repair. The subsystem repair step includes, according to the confidence of each single component from large to small, when repairing a mechanical system fault, the maintenance inspection of the crank arm, base, buffer and rotating shaft is carried out in sequence; when repairing an electrical system fault, the conductor loop is maintained first and then the contact is maintained; when repairing an insulation system fault, the maintenance sequence is carried out according to SF6 gas and insulating parts; the multi-component combination repair step includes, based on the correlation between component faults, with the goal of reducing the maintenance time of the high-voltage circuit breaker and reducing the overall disassembly cost of the equipment, forming two maintenance combinations, the first combination is the rotating shaft, crank arm and conductor loop, and the second combination is the buffer, contact and SF6 gas; when a component in the combination fails, the other components are simultaneously inspected and maintained. It reduces the maintenance time of the high-voltage circuit breaker by using two maintenance combinations through the steps of subsystem repair and multi-component combination repair.

[0065] Please refer to the detailed description of the specific implementation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1-1 is the data flow graph of fault propagation path one;

[0067] Figure 1-2 It is the data flow graph of fault propagation path 2;

[0068] Figure 2 It is a data flow diagram for combined maintenance effect evaluation. DETAILED DESCRIPTION

[0069] According to the composition structure, high-voltage circuit breakers can be divided into three subsystems: mechanical system, electrical system and insulation system. Failure of each subsystem will cause the circuit breaker to stop operating. Considering the faulty components, mechanical system failures are mainly caused by insufficient lubrication of the crank arm in the operating mechanism, stuck shafts, etc., electrical system failures are mainly caused by excessive conductor loop resistance and contact wear, and insulation system failures are mainly caused by SF6 gas failure in the gas chamber and partial discharge of insulating parts. In the previous multi-component maintenance theory of high-voltage circuit breakers, the influence of factors such as spatial position, structural design and operating environment was ignored. It was assumed that the failures of each subsystem and component were independent of each other, that is, there was no connection between the failure probabilities. In fact, the failure probabilities of each subsystem and component of the high-voltage circuit breaker have a certain correlation. According to on-site operation and maintenance experience, the degradation of buffer performance will increase the risk of contact wear, and contact wear will increase the probability of SF6 gas failure. Completely breaking the fault correlation between multiple components will reduce the overall maintenance effect of the high-voltage circuit breaker, bringing certain safety hazards and economic losses.

[0070] As a typical multi-component system, there are complex fault, structural and economic coupling between the components of high-voltage circuit breakers. It is necessary to formulate a scientific and reasonable maintenance strategy for high-voltage circuit breakers to achieve a balance between safety, stability and economic benefits. The analysis steps are as follows:

[0071] The inventor counted 420 high-voltage circuit breaker failure cases in a power grid company's equipment fault database from 2010 to 2023, and proposed a multi-component maintenance strategy for high-voltage circuit breakers that takes fault correlation into consideration. The association rule method is used to calculate the failure risk of a single component in each subsystem of the high-voltage circuit breaker. The correlation between multi-component failures is quantitatively analyzed by the chi-square test and odds ratio method. From the perspective of combined maintenance optimization effect, the correlation of multi-component combined maintenance is evaluated, aiming to reduce the number of power outages and maintenance costs while ensuring the safe operation of the circuit breaker.

[0072] 1 Obtain fault samples

[0073] As shown in Table 1, based on 420 high-voltage circuit breaker failure cases, a single-component failure statistics table was obtained by counting single-component failures. Single-component failures include loose base, stuck shaft, buffer performance degradation, insufficient arm lubrication, excessive conductor loop resistance, contact wear, SF6 gas failure, and partial discharge of insulating parts.

[0074] As shown in Table 2, a subsystem failure statistics table is obtained by counting subsystem failures. Subsystem failures include mechanical system failures, electrical system failures, and insulation system failures.

[0075] Table 1: Statistics of single component failures

[0076]

[0077] Table 2: Subsystem failure statistics

[0078]

[0079] The statistical results show that single component failures coexist and there is a significant correlation between failures. The failures of loose base, degraded buffer performance, stuck shaft, excessive conductor loop resistance and insufficient arm lubrication account for a high proportion, which are 67.62%, 48.09%, 47.14%, 46.67% and 44.29% respectively. Among the subsystem failures, mechanical system failures account for 77.62%, electrical system failures account for 57.86% and insulation system failures account for 25.95% respectively.

[0080] 2. Risk analysis of single component failure in subsystem

[0081] Considering the correlation between single component failures in the high-voltage circuit breaker subsystem, some single components with frequent failures are not necessarily the root causes of subsystem failures. It is necessary to quantitatively analyze the failure risks of each single component in the subsystem and implement differentiated maintenance for each single component to improve the pertinence of subsystem maintenance.

[0082] Association rules quantitatively describe the correlation between different items in the same event by mining the hidden associations between them. The basic definition of association rules is as follows:

[0083] 1) The transaction database D is a set of subset transactions T, D = {T1, T2..., T n}, the number of subset transactions is n. Subset transaction T = {i1,i2,...,i m}, i is called an item, and the number of items is m. A and B are subsets of i, called item set A and item set B.

[0084] 2) The support of item set A is the number of transactions in D that contain item set A, denoted as σ(A).

[0085]

[0086] In formula (1), σ(A) is the support of item set A, D is the transaction database, and T is the subset transaction of transaction database D.

[0087] 3) If the item set and A is the premise of association rule A→B, B is the conclusion of association rule A→B, and the support of A→B is the ratio of A∪B in D, which is recorded as:

[0088] Sup(A→B)=P(A∪B) (2)

[0089] In formula (2), Sup(A→B) is the support of A→B.

[0090] 4) The conditional probability P(B|A) in database D represents the confidence of the association rule A→B, which is denoted as

[0091]

[0092] In formula (3), C(A→B) is the confidence of association rule A→B.

[0093] The association rules are applied to the risk analysis of single component failure in high-voltage circuit breaker subsystem. The support and confidence of single component failure are calculated to quantitatively describe the influence of single component on subsystem failure.

[0094] Define as follows:

[0095] 1) D = {high-voltage circuit breaker failure caused by subsystem failure}, where D is a transaction database formed by the high-voltage circuit breaker failure caused by the subsystem failure;

[0096] 2) B = {subsystem failure caused by single component failure};

[0097] 3) A i = {high voltage circuit breaker failure caused by single component failure}, A i Represents the i-th single component in the subsystem.

[0098] Use equations (4) and (5) to calculate association rule A respectively i →The support and confidence of B.

[0099]

[0100] In formula (4), Sup(A i →B) is association rule A i →The support of B.

[0101]

[0102] In formula (5), C(A i →B) is association rule A i →B's confidence level.

[0103] Taking mechanical system failure as an example, the support and confidence of single component failure are calculated. There are 420 high-voltage circuit breaker failure samples in total, 326 of which are caused by mechanical system failure. Among these 326 mechanical system failures, the number of failures caused by loose base, stuck shaft, degraded buffer performance and insufficient lubrication of crank arm are 214, 128, 132 and 152 respectively. The number of circuit breaker failures caused by loose base, stuck shaft, degraded buffer performance and insufficient lubrication of crank arm are 284, 198, 202 and 186 respectively.

[0104] According to the definition of association rules, we have |D|=326, σ(A1)=284, σ(A2)=198, σ(A3)=202, σ(A4)=186, σ(A1∪B)=214, σ(A2∪B)=128, σ(A3∪B)=132, σ(A4∪B)=152.

[0105] The support degree of loose foundation is calculated according to formula (4):

[0106]

[0107] Similarly, the support degrees of shaft jamming, buffer performance degradation and insufficient arm lubrication are calculated to be 0.3926, 0.4049 and 0.4663 respectively.

[0108] The confidence level of foundation looseness is calculated according to formula (5):

[0109] Similarly, the confidence levels of shaft jamming, buffer performance degradation, and crank arm lubrication deficiency are calculated to be 0.6465, 0.6535, and 0.8172, respectively.

[0110] Based on the statistical data in Table 1 and Table 2, the support and confidence of single component failure when the high-voltage circuit breaker subsystem fails are calculated, and the results are shown in Table 3.

[0111] Table 3: Analysis of association rules between subsystem failure and single component failure

[0112]

[0113] It can be seen that the support of each single component failure is greater than 0.35, indicating that the statistics based on subsystem failure and single component failure are reasonable. The confidence level indicates the probability of a single component failure at the same time when a subsystem fails, that is, when repairing the mechanical system, electrical system, and insulation system of the high-voltage circuit breaker, each single component should be differentially maintained from high to low according to the confidence level to achieve a balance between maintenance effect and maintenance efficiency.

[0114] 3. Multi-component fault correlation analysis

[0115] High-voltage circuit breakers are complex systems composed of multiple interconnected and interacting components. When making maintenance decisions, the propagation and coupling between faults of each component must be considered.

[0116] The chi-square test is a widely used nonparametric hypothesis testing method. It analyzes the correlation between two variables by comparing the degree of deviation between the theoretical frequency and the actual frequency. The calculation formula is shown in formula (6).

[0117]

[0118] In formula (6), χ 2 is the chi-square test statistic, χ 2 The larger the value, the closer f0 is to f e The larger the correlation, the greater the actual frequency f0 represents. e Indicates the theoretical frequency.

[0119] Odds ratio (OR), or odds ratio, is a basic indicator in control studies, used to describe the relative risk of exposure to a factor compared to not being exposed to the factor. Define the failure rate of a single component in a subsystem of a high-voltage circuit breaker as a, the non-failure rate as b, and the failure rate of a single component in the control subsystem as c, the non-failure rate as d. The formula for calculating the odds ratio is shown in formula (7).

[0120] OR=(a / b) / (c / d) (7)

[0121] In formula (7), OR is the risk of a factor, which is the relative risk of not being exposed to the factor. The failure rate of a single component in a subsystem of a high-voltage circuit breaker is a, and the non-occurrence rate is b. The failure rate of a single component in a control subsystem is c, and the non-occurrence rate is d.

[0122] SPSS24.0 data analysis software was used to perform chi-square tests and odds ratio calculations to analyze whether the correlation between single component failures of high-voltage circuit breakers was significant. In the chi-square test, p < 0.05 and OR > 1 indicated that there was a significant correlation between single component failures, as shown in Table 4, which only listed single component failures with correlation.

[0123] Table 4: Chi-square test and OR value table for multiple component failures

[0124]

[0125]

[0126] It can be seen from Table 4 that the shaft jamming, insufficient arm lubrication and excessive conductor loop resistance faults are significantly correlated, the buffer performance degradation, contact wear and SF6 gas failure faults are significantly correlated, and there are two propagation paths between component faults.

[0127] like Figure 1-1 As shown, in path one, the ratios of shaft jamming and insufficient arm lubrication to excessive conductor loop resistance are 1.367 and 1.382, respectively, indicating that shaft jamming and insufficient arm lubrication will increase the possibility of excessive conductor loop resistance to 1.367 times and 1.382 times the original.

[0128] like Figure 1-2 As shown in Figure 2, in path 2, the decrease in buffer performance will increase the possibility of contact wear to 2.967 times the original value. The ratio of contact wear to SF6 gas failure is 3.525, indicating that contact wear will increase the possibility of SF6 gas failure to 3.525 times the original value.

[0129] The functions and failure rules of each single component in a high-voltage circuit breaker are different, and the applicable maintenance methods and maintenance timing are also different. If the system maintenance is performed according to the maintenance timing of a single component, the high-voltage circuit breaker will be frequently shut down. Grouping as many single component maintenance tasks as possible and implementing a certain degree of combined maintenance of fault-related components can effectively reduce the number of power outages of high-voltage circuit breakers, which has engineering promotion and application value.

[0130] 4. Get a Repair Strategy

[0131] The steps of subsystem maintenance and multi-component combined maintenance are proposed by considering the failure risk size of a single component and the correlation between multi-component failures when a high-voltage circuit breaker subsystem fails.

[0132] At this point, the analysis steps are completed.

[0133] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0134] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0135] The present invention discloses a method for repairing multiple components of a high-voltage circuit breaker based on fault correlation, including the steps of subsystem repair and multiple component combined repair.

[0136] The steps of subsystem maintenance include: according to the confidence level of each single component, when repairing a mechanical system fault, the crank arm, base, buffer and shaft are maintained and inspected in sequence; when repairing an electrical system fault, the conductor circuit is maintained first and then the contacts are maintained; when repairing an insulation system fault, the maintenance order is based on SF6 gas and insulating parts.

[0137] The steps of multi-component combination maintenance include: based on the correlation between component failures, with the goal of reducing the maintenance time of high-voltage circuit breakers and reducing the overall disassembly cost of equipment, two maintenance combinations are formed. The first combination is the rotating shaft, crank arm and conductor loop, and the second combination is the buffer, contact and SF6 gas. When a component in the combination fails, the other components are inspected and maintained simultaneously.

[0138] Following the above analysis steps, a step of combined maintenance effect evaluation is also included, which is detailed as follows.

[0139] 5Combination maintenance effect evaluation

[0140] 5.1 Evaluation Metrics

[0141] The optimization of high-voltage circuit breaker combined maintenance is related to many factors, including fault correlation degree, design parameters, structural performance, maintenance costs, personnel and equipment, etc.

[0142] like Figure 2 As shown, with reference to relevant standards such as BS6867-1987, Code of Practice for Maintenance of Electrical Switches with Voltages Higher than 36kV, DL / T302.1-2011, and NB / T20223-2013, the Maintenance Guidelines for Safety-Important Mechanical Equipment in Nuclear Power Plants, the reliability, safety, economy, and integrity of the maintenance optimization effect are used as evaluation indicators for the combined maintenance effect of high-voltage circuit breakers. The first combination is combination 1, and the second combination is combination 2.

[0143] The strength of the evaluation index of the multi-component combination maintenance of high-voltage circuit breakers can be divided into four levels: none, small, medium, and large. The fuzzy statistical method and scale scoring method are used to quantify the specific indicators within the range of 0 to 3, and the matrix expression is shown in formula (8).

[0144]

[0145] In formula (8), U is the strength matrix of the evaluation index of the combined maintenance of high-voltage circuit breakers, and u1~u4 represent reliability, safety, economy and integrity, respectively.

[0146] 5.2 Evaluation of combined maintenance effect based on product-sum formula

[0147] The evaluation indicators of the maintenance effect of the multi-component combination of high-voltage circuit breakers affect each other. For example, when the integrity of the equipment is improved, the reliability will also be improved accordingly, but the economic efficiency of the maintenance may deteriorate. It is necessary to consider the interaction between the evaluation indicators. The interaction matrix expression of the four evaluation indicators is shown in formula (9).

[0148]

[0149] In formula (9), F is the interaction matrix of the mutual influence between the evaluation indicators of the maintenance effect of multiple components of high-voltage circuit breakers, f ij is the interaction value of indicator i on indicator j. In order to be consistent with the quantitative range of indicator strength, 0 to 3 points are used to represent no interaction, weak interaction, moderate interaction and strong interaction.

[0150] The combined maintenance effect evaluation comprehensive matrix M is defined as shown in formula (10). The elements in M ​​reflect the comprehensive characteristics of the maintenance evaluation index, examine the maintenance association between component combinations, and the values ​​of each evaluation index and the interaction between the indicators can be quantitatively expressed by the matrix M.

[0151]

[0152] In formula (10), M is the comprehensive matrix for combined maintenance effect evaluation.

[0153] The product-sum formula is widely used in combinatorial mathematics, computer networks, multi-target tracking, and statistical physics, and can deal with problems involving the mutual influence of different indicators.

[0154] The product-sum formula is defined as follows: n-order matrix A = (a ij ) n×n The product-sum formula of is shown in formula (11).

[0155]

[0156] In formula (11), per(A) is a comprehensive evaluation index of reliability, safety, economy and integrity, σ(i) is the element at the i-th position of σ, S n is the set of all possible permutations.

[0157] The product-sum formula is applied to the evaluation model of the combined maintenance effect of high-voltage circuit breakers. On the basis of the comprehensive matrix of the combined maintenance effect evaluation, the product-sum formula is used to reflect the influence of the interaction between indicators on the entire evaluation. The larger the comprehensive index, the better the combined maintenance effect, which is used to judge different combined maintenance schemes.

[0158] 5.3 Calculation example

[0159] Combined maintenance is performed on fault-related parts and non-fault-related parts respectively, and the four indicators of reliability, safety, economy and integrity are used to evaluate the combined maintenance effect. Taking the first maintenance combination with significant fault correlation and the third maintenance combination with no fault correlation as examples, the evaluation index strength of the two maintenance combinations is scored with reference to the American mechanical equipment maintenance standard MIL-HDBK-472. The specific scores are shown in Table 5, and the evaluation index strength matrices UI and U3 are obtained.

[0160] The first combination includes a rotating shaft, a crank arm and a conductor loop, and the first combination is combination 1. The third combination includes a loose base and a conductor loop, and the third combination is combination 3.

[0161] Table 5: Evaluation index scoring table

[0162]

[0163]

[0164] By collecting and analyzing literature and consulting experts, the interaction values ​​between the maintenance evaluation indicators of the first combination are determined:

[0165] f 12 =2, f 13 =3, f 14 =2, f 21 =3, f 23 =3, f24 =1, f 32 =2, f 34 =3, f 41 =1, f 42 =2,

[0166] The interaction value between the maintenance evaluation indicators of combination 3: f 12 =3, f 14 =2, f 21 =3, f 23 =3, f 31 =1, f 32 =2, f 34 =3, f 41 =2, f 43 =1, and the evaluation index interaction matrices F1 and F3 of combination 1 and combination 3 are obtained.

[0167]

[0168] Substituting the evaluation index intensity matrix U and the evaluation index interaction matrix F of the two combination schemes into formula (10), we can obtain the combined maintenance evaluation comprehensive matrices M1 and M3 of the two schemes.

[0169]

[0170] The calculation results show that per(M1)=256 and per(M3)=241, that is, the maintenance correlation of combination 1 is better than that of combination 3, which is consistent with the result of component combination considering fault correlation. The same method is used to calculate per(M2)=285, that is, the maintenance optimization effect of combination 2 is better than that of combination 1. Combination 1 includes the shaft, crank arm and conductor loop, combination 3 includes base looseness and conductor loop, and combination 2 includes buffer, contact and SF6 gas.

[0171] Summary: Based on the correlation between multi-component faults of high-voltage circuit breakers, this application quantitatively analyzes the failure risk of a single component in a subsystem and the coupling between multi-component faults, and proposes a high-voltage circuit breaker subsystem and multi-component combination maintenance strategy. In the case analysis part, by evaluating the maintenance optimization effect of different component combinations, the rationality of multi-component combination maintenance considering fault correlation is verified. This provides theoretical reference and engineering application experience for the formulation of high-voltage circuit breaker maintenance strategies.

[0172] With the rapid development of smart grids, the fault tolerance of high-voltage circuit breakers is getting smaller and smaller. The drawbacks of over-maintenance or under-maintenance in the maintenance mode based on component independence are becoming increasingly prominent. A multi-component maintenance strategy for high-voltage circuit breakers considering fault correlation is proposed. The failure risk of a single component in the high-voltage circuit breaker subsystem is calculated using association rules. The correlation between multi-component failures is analyzed by chi-square test and odds ratio, and the maintenance correlation is evaluated based on the optimization effect of multi-component combined maintenance.

[0173] Compared with traditional high-voltage circuit breaker maintenance strategies, subsystem maintenance strategies and multi-component combination maintenance strategies that consider fault-related issues can improve circuit breaker maintenance effects while reducing the number of power outages, taking into account both circuit breaker availability and maintenance economy.

Claims

1. A multi-component maintenance method for a high-voltage circuit breaker based on fault correlation, characterized in that: It includes the steps of subsystem maintenance and multi-component combination maintenance. The steps of subsystem maintenance include following the confidence level of each single component failure from large to small. When repairing mechanical system failure, the crank arm, base, buffer and shaft are maintained and inspected in sequence. When repairing an electrical system failure, first maintain the conductor circuit and then the contacts; When repairing an insulation system failure, the maintenance sequence is based on SF6 gas and insulating parts; the steps for multi-component combination maintenance include forming two maintenance combinations based on the correlation between component failures, with the goal of reducing the maintenance time of high-voltage circuit breakers and reducing the overall disassembly cost of the equipment. The first combination is the rotating shaft, crank arm and conductor loop, and the second combination is the buffer, contact and SF6 gas; when a component in the combination fails, the other components are inspected and maintained simultaneously.

2. The method for repairing multiple components of a high-voltage circuit breaker based on fault correlation according to claim 1, characterized in that: It also includes an analysis step for obtaining the subsystem maintenance and multi-component combination maintenance steps, the analysis step includes a fault sample acquisition step, the fault sample acquisition step includes obtaining a single component fault statistics table by performing statistics according to single component faults, the single component faults include loose base, stuck shaft, buffer performance degradation, insufficient arm lubrication, excessive conductor loop resistance, contact wear, SF6 gas failure and partial discharge of insulating parts; the subsystem fault statistics table is obtained by performing statistics according to subsystem faults, the subsystem faults include mechanical system faults, electrical system faults and insulation system faults.

3. The method for repairing multiple components of a high-voltage circuit breaker based on fault correlation according to claim 2, characterized in that: The step of obtaining fault samples also includes that single component faults coexist and there is fault correlation, and the faults of loose base, degraded buffer performance, stuck shaft, excessive conductor loop resistance and insufficient crank arm lubrication account for a high proportion; Among subsystem failures, mechanical system failures account for a relatively high proportion.

4. The method for repairing multiple components of a high-voltage circuit breaker based on fault correlation according to claim 2, characterized in that: The analysis step also includes a single component failure risk analysis step within the subsystem, and the single component failure risk analysis step within the subsystem includes the following steps: The association rules are applied to the risk analysis of single component failure in the high-voltage circuit breaker subsystem. By calculating the support and confidence of single component failure, the influence of single component on subsystem failure is quantitatively described. Association rules quantitatively describe the correlation between different items in the same event by mining the hidden associations between them. The basic definition of association rules is as follows: The transaction database D is a collection of subset transactions T, D = {T1, T2..., T n }, the number of subset transactions is n; subset transaction T = {i1,i2,...,i m }, i is called an item, the number of items is m; A and B are subsets of i, called item set A and item set B; The support of item set A is the number of transactions in D that contain item set A, denoted as σ(A); In formula (1), σ(A) is the support of item set A, D is the transaction database, and T is the subset transaction of transaction database D; If the item set And A∩B=Φ, A is the premise of association rule A→B, B is the conclusion of association rule A→B, and the support of A→B is the ratio of A∪B in D, which is recorded as: Sup(A→B)=P(A∪B) (2) In formula (2), Sup(A→B) is the support of A→B; The conditional probability P(BA) in database D represents the confidence of association rule A→B, which is denoted as In formula (3), C(A→B) is the confidence of association rule A→B.

5. The method for repairing multiple components of a high-voltage circuit breaker based on fault correlation according to claim 4, characterized in that: The single component failure risk analysis step in the subsystem also includes the following steps: Define as follows: 1) D = {high-voltage circuit breaker failure caused by subsystem failure}, where D is a transaction database formed by the high-voltage circuit breaker failure caused by the subsystem failure; 2) B = {subsystem failure caused by single component failure}; 3) A i = {high voltage circuit breaker failure caused by single component failure}, A i represents the i-th single component in the subsystem; Use equations (4) and (5) to calculate association rule A respectively i →B's support and confidence; In formula (4), Sup(A i →B) is the support of association rule Ai→B; In formula (5), C(A i →B) is the confidence of the association rule Ai→B.

6. The method for repairing multiple components of a high-voltage circuit breaker based on fault correlation according to claim 5, characterized in that: The single component failure risk analysis step within the subsystem also includes the following steps: when repairing the mechanical system, electrical system and insulation system of the high-voltage circuit breaker, each single component should be differentially maintained from high to low confidence level to achieve a balance between maintenance effect and maintenance efficiency.

7. The method for repairing multiple components of a high-voltage circuit breaker based on fault correlation according to claim 2, characterized in that: The analysis step further includes a multi-component fault correlation analysis step, which includes: High-voltage circuit breakers are complex systems composed of multiple interconnected and interacting components. When making maintenance decisions, it is necessary to consider the propagation and coupling between the faults of each component. The chi-square test is a widely used nonparametric hypothesis testing method. It analyzes the correlation between two variables by comparing the degree of deviation between the theoretical frequency and the actual frequency. The calculation formula is shown in formula (6); In formula (6), χ 2 is the chi-square test statistic, χ 2 The larger the value, the closer f0 is to f e The larger the correlation, the greater the actual frequency f0 represents. e represents the theoretical frequency; Odds ratio (OR), also known as odds ratio, is used to describe the relative risk of exposure to a factor to that of not being exposed to the factor. Define the failure rate of a single component in a subsystem of a high-voltage circuit breaker as a, and the non-failure rate as b, and the failure rate of a single component in a control subsystem as c, and the non-failure rate as d. The formula for calculating the odds ratio is shown in formula (7); OR=(a / b) / (c / d) (7) In formula (7), OR is the risk of a factor, which is the relative risk of not being exposed to the factor. The failure rate of a single component in a subsystem of a high-voltage circuit breaker is a, and the non-occurrence rate is b. The failure rate of a single component in a control subsystem is c, and the non-occurrence rate is d. SPSS24.0 data analysis software was used to perform chi-square test and odds ratio calculation to analyze whether the correlation between single component failures of high-voltage circuit breakers was significant; in the chi-square test, p < 0.05 and OR > 1 indicated that there was a significant correlation between single component failures.

8. The method for repairing multiple components of a high-voltage circuit breaker based on fault correlation according to claim 7, characterized in that: The multi-component fault correlation analysis step also includes the following steps: There is a significant correlation between the shaft jamming, insufficient arm lubrication and excessive conductor loop resistance faults. There is a significant correlation between the buffer performance degradation, contact wear and SF6 gas failure faults. There are two propagation paths between component faults. In path 1, through the ratio of shaft jamming, insufficient lubrication of the crank arm and excessive conductor loop resistance, it is known that shaft jamming and insufficient lubrication of the crank arm will increase the possibility of excessive conductor loop resistance; In path two, the degradation of buffer performance will increase the possibility of contact wear, and contact wear will increase the possibility of SF6 gas failure.

9. The method for repairing multiple components of a high-voltage circuit breaker based on fault correlation according to claim 1, characterized in that: The method also includes a combined maintenance effect evaluation step, which includes the following steps: reliability, safety, economy and integrity in the maintenance optimization effect are used as evaluation indicators of the combined maintenance effect of the high-voltage circuit breaker; The strength of the evaluation index of the multi-component combination maintenance of high-voltage circuit breakers is divided into four levels: none, small, medium, and large. The fuzzy statistical method and scale scoring method are used to quantify the specific indicators within the range of 0 to 3, and the matrix expression is shown in formula (8); In formula (8), U is the strength matrix of the combined maintenance evaluation index of high-voltage circuit breakers, and u1~u4 represent reliability, safety, economy and integrity, respectively.

10. The method for repairing multiple components of a high-voltage circuit breaker based on fault correlation according to claim 9, characterized in that: The combined maintenance effect evaluation step further includes the following steps: based on the combined maintenance effect evaluation of the product-sum formula, the interaction matrix expression of the four evaluation indicators is shown in formula (9); In formula (9), F is the interaction matrix of the mutual influence between the evaluation indicators of the maintenance effect of multiple components of high-voltage circuit breakers, f ij is the interaction value of indicator i on indicator j; in order to be consistent with the quantitative range of indicator strength, 0 to 3 points are used to represent no interaction, weak interaction, moderate interaction and strong interaction; Define the comprehensive matrix M for combined maintenance effect evaluation, as shown in formula (10); the elements in M ​​reflect the comprehensive characteristics of the maintenance evaluation index, examine the maintenance association between component combinations, and each evaluation index value and the interaction between the indicators are quantitatively expressed by the matrix M; In formula (10), M is the comprehensive matrix for combined maintenance effect evaluation; The product-sum formula is defined as follows: n-order matrix A = (a ij ) n×n The product and sum of is shown in formula (11); In formula (11), per(A) is a comprehensive evaluation index of reliability, safety, economy and integrity, σ(i) is the element at the i-th position of σ, S n is the set of all possible permutations; The product-sum formula is applied to the evaluation of the combined maintenance effect of multiple components of high-voltage circuit breakers. The larger the comprehensive index, the better the combined maintenance effect.

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