Safety Risk Analysis of insulators in Electric transmission Line Based on Fuzzy Fault Tree Method

This text put forward a kind of analytical method which analyzes the fault causes by layer upon layer based on the statistic, and identifies the safety risk of the insulators. This analytical method uses the way named FTA (Fault Tree Analysis) in reliability evaluation. Given that the fault probability caused by the strong storm is undefined, this paper regards the probability of the basic event as fuzzy datum, and illustrates the whole analysis process of the safety risk of the insulators based on the fault tree logic structure of intermediate and top events. According to the fault tree analysis we can build math model. This model uses the theory of the Fussell-Vesely in reliability evaluation to work out the minimum cut sets, and using the minimum cut sets to make the fault tree. Furthermore, based on the coefficient which was given by experts in work field and the calculation theory of FTA, the calculation formula of operating risk assessment for insulators was given accordingly. Combined with practice, it analyzes and calculates the reliability indexes of the insulators. The applied example shows that it is possible and applicable to use the fuzzy fault tree method in analyzing the safety risk of the insulators accidents of electric transmission line hierarchically.