Importance evaluation method on the fault modes of power transformer based on trapezoidal fuzzy number

The fault modes of the components of the power transformer is complex and highly correlated, and the implementation of reliability tests is difficult because of the high value of the equipment, so it is hard to make importance evaluation by using traditional method. Aiming at those problems, a new evaluation method on importance based on trapezoidal fuzzy number is proposed in this paper. Firstly, the evaluation index system of importance is established which using the Delphi method to formulate the score rating criteria and applying the coordination degree to amend the scores. Secondly, the trapezoidal fuzzy numbers is applied to determine the weight indicator. Last, the importance of each failure mode of transformer is determined on the basis of the indicator combining with the weight through the linear weighting method. It is shown by the instance that this method is convenient and effective, which can be used in making the reliability evaluation and maintenance decision of the power transformer.