The Condition Assessment Method For HV Circuit Breakers Based On FAHP

With the development of society, the scale of power grid has been expandedunprecedentedly. Thanks to the constant enlargement of the scale of power grid, the demandfor safety and reliability in electric power system is faced with greater challenge. High voltagecircuit breaker, as essential equipment in electric power system, has a dual function ofcontrolling and protecting in the system. Master its running state timely and accurately,diagnose its potential fault, reasonably arrange the maintenance scheduling not only makessure the safe and stable operation of the electric system, but also saves the cost of overhauland realizes the breaker’s condition based maintenance, which has both economic and socialsignificances.Currently, the condition assessment of high voltage circuit breaker is one of the mainmatters of condition assessment theory of electronic equipment and technology applicationresearch. The determination of index weight relies on personal experience. Fuzziness ofpersonal judgment and subjective randomness may lead to uncertainty of evaluation resultsand even mistakes, fuzzy analytic hierarchy process (AHP) improved from triangular fuzzynumber is introduced to determine the index weight. With regard to the problem that indexfunction uses the ready-made mathematical function, stressing the fuzziness of index andignoring the randomness, the normal cloud model is adopted to determine the index function.Besides, the fuzzy analytical hierarchy process is applied to carry out fuzzy assessment onhigh voltage circuit breaker. For these purposes, following things are done:Firstly, According to the existing state of high voltage circuit breaker testing level andtechnology in China, plus the operation records and working experience of operationmaintenance of high voltage circuit breaker, relative electrical wear, using years, open circuitnumber, instant speed and just closing speed, switching time, the pressure of the insulatingmedium, leakage and the working environment etc. are factors influence evaluationparameters of the operation of circuit breaker.Secondly, According to the structure of the circuit breaker, combining with the circuitbreaker fault type, hierarchical decomposition is carried out on established evaluation index,multi-level evaluation model of the high voltage circuit breaker comes into being; and, according to the influence degree on each index of circuit breaker parts or the whole runningstate, fuzzy analytic hierarchy process (AHP) improved from triangular fuzzy number isintroduced to determine the index weight.Finally, Determine the minimum level of membership based on the characteristics of itsvarious factors, using the normal cloud, model and expert statistics; combining with theweight coefficient of index, the bottom assessment of the status of evaluation factors is got;the overall circuit breaker operation state is finally got through the layered recursivecomputation.By applying the improved fuzzy analytic hierarchy process (AHP) as determined in thispaper to the actual operation assessment of different voltage grade and the operation of circuitbreakers, the validity and reliability of this method are verified.