Study Of The Condition Assessment Method For High Voltage Circuit Breaker Based On Matter-element And Evidence Theory

High voltage circuit breaker is the most broadly applied high voltage electric devices in power systems. The status of breakers directly influences power system's stability and reliability. The tradition scheduled maintenance or Time Based Maintenance has some serious defects. Condition Based Maintenance (CBM), being based upon condition monitoring, is the most advanced maintenance program nowadays. The key of CBM is to grasp the operating condition of high circuit breaker accurately. So it is of great importance to direct CBM and improve the reliability of power system.Based on the analysis of circuit breaker condition information, an index system of circuit breaker condition assessment according engine parameter and electric parameter and so on has been built.The influence degree to the state of the circuit breaker is different according to each evaluation factor, adopt the improved analytic hierarchy process (IAHP) to confirm the constant weight. At the same time by introducing the variable weight model based in balanced function, the paper modifies the constant weight, which makes the weight distribution more reasonable and objective.A hierarchical model was adopted, in order to avoid the over complexity of model while using the circuit breaker condition information adequately. The index of model can be added or removed according to the practical situation, which makes the model has good expansibility and flexibility. Matter-element theory is adopted to assess the primary model, which confirms the classical region by relative impairment grade and analyses ascription degree of each index with relevancy function. Thus incompatibility issue is resolved and the assessment result is better. Evidence theory is adopted to assess the secondary model. Reliability factorα, as the index weight, is introduced to evidence theory, so that the different importance of each evidence can be shown and the evidence conflict be avoided.Through the examination of actual circuit breaker, the condition assessment model for high voltage circuit breaker building by the paper is effective. It provides a new way to know the circuit breaker status in time.