Health Index of MEA Power Transformers for Preventive Maintenance by Using Fuzzy Analytic Hierarchy Process

Abstract

This paper presents an analytical method to evaluate the health index of power transformers by using weighted scores for transformer’s risk factors. The weighted scores for risk factors are obtained from Fuzzy Analytic Hierarchy Process (FAHP) which applies the Fuzzy Set theory for addressing the effects of risk factors considering the decision making uncertainty. The FAHP compares the effects of risk factors in pairs in order for calculating their weighted scores as well as checking for the correlation of the assigned effects of risk factors. The weighted scores are then used to calculate the health index in order to evaluate the risk for power transformers in the substations of Metropolitan Electricity Authority (MEA) and plan for their annual preventive maintenance. In this study, the risk factors are categorized into two parts: (1) the risk factors for on load tap changer and (2) the risk factors for transformer main tank. The proposed method is tested on fifteen MEA’s power transformers. The study results show that the obtained health indices correctly reflex the conditions of those power transformers. Therefore this method is a useful tool for the planning of preventive maintenance schedule for power transformers