Study On Condition Assessment Of High-Voltage SF₆Circuit Breaker

High voltage circuit breaker was designed to take in charge of the control and protection functions in the power system, which means the safety and stable operation of High voltage circuit breaker also determine the regional power system fault is isolation at times in the abnormal state and arrangements the common schedule in the abnormal state. Therefore, reasonably and accurately operation of circuit breaker for the security and stability of the entire power system is of great significance.A new index system of condition assessment based on analysis of the function of circuit-breaker has been built, which include function of drive, current path, insulation and interrupter. Circuit-breaker would keep in the opening or closing state in long-term, but the main task of circuit-breaker is to make or interrupt the current when the state is changed.The condition assessment index system of function has been integrated by quantitative hierarchical state performance indicators and the qualitative status indicators.The value of set pair membership function counted from quantitative condition indicators have used as the probability assignment of hierarchical evidence theory. To combined the membership function and the Ornstein-Uhlenbeck process, the condition assessment membership function could represent both the fuzziness and Randomness.Before combination of the quantitative status indicators, the the evidence conflicts-consistency need to be determined. When the degree of conflict for evidence theory methods is low, the degree of conflict was set as the unknown element assigned to evidence recognition framework.When the degree of conflict for evidence theory methods process is high; the method of similarity coefficient weighted method combination is used to combin the evidence. By evidence combination, The quantitativ condition assessment resultse of status indicator was obtained. On-site equipment maintenance personnel has been inquired about in the form of a questionnaire about the condition of the certain circuit-breaker.The set pair analysis method has been used to analisis these data. To conbine the conclution of quantitative analysis and the qualitative analysis by decision tree method, the maintenance schem could be settled.The method introduced in this papper has been used to two instances of high voltage circuit breaker. Compared with the result of fuzzy evaluation method, it proves that the method introduced in this papper is effective.