Research Of The Reliability Of Active ECT

Current transformer is a critical equipment for metering and protection in power system. With the continuous development of digitization and intelligence of power system, traditional electromagnetic current transformer due to its own constraints of operational principle make it difficult to meet the increasingly stringent requirements of power system. All kinds of new electronic current transformer(ECT) have gradually replaced the traditional electromagnetic current transformer because of its superior performance, in which Active ECT is currently a hot spot of research. Therefore, it's very important to research the reliability of Active ECT both in theory and in practice. In this paper, a applicable program of reliability evaluation method is explored, which evaluated the reliability indexes of Active ECT, the research contents, methods and conclusions have reference value for the research, design and manufacture of Active ECT.In this paper, based on the reliability index, the reliability evaluation of Rogowski coil ECT is carried out by means of reliability analysis, reliability prediction and reliability simulation. First, the fault tree analysis method is used to analyze the reliability of the system, in order to find out the weak link of the Rogowski coil ECT system; Then the combined method of element counting and stress analysis is used to predict the reliability of the system, the failure rate and the average life expectancy of the system are calculated; At last, Monte Carlo method is used to simulate the reliability of the system, the Failure probability distribution curve, the reliability curve and the average life expectancy of the system are calculated.The research results show that, the first order minimum cut sets account for 81 percent of the all the minimum cut sets of fault tree in Active ECT. In the design process, the number of minimal cut sets should be reduced as much as possible; After the use of about 37500 hours, the reliability of the Active ECT dropped to 0.5, and the average life expectancy of the Active ECT is about 7 years; Active ECT system has the highest probability of failure at the initial stage of operation, with the accumulation of running time, the probability of failure will be gradually reduced.