Reliability assessment of monitoring device for mechanical failure of high voltage circuit breaker based on FTA

Mechanical failure is the main failure of high voltage circuit breaker. In order to forecast the mechanical failure of the circuit breaker accurately, it is essential to estimate the electromagnetic compatibility (EMC) and reliability about the monitoring device. This paper proposes the method of reliability estimation of mechanical failure of monitoring device for circuit breaker based on fault-tree analysis (FTA). The fault tree model is established on the structure of monitoring device for high voltage circuit breaker. It involves data acquisition, signal analysis, fault diagnosis and data management. Aiming at a rigorous analysis process, the electromagnetic environment is taken into account. Considering the features of every characteristic, the relative inferiority degree and membership function are used to evaluate fault probabilities synthetically. Meanwhile, the fuzzy analysis hierarchy process (FAHP) is adopted to define importance weight of basic event. Minimal cut set method is taken to assess the reliability of monitoring device. This analysis method can estimate the reliability of mechanical failure of monitoring device for high voltage circuit breaker effectively.