Cloud model-based failure mode and effects analysis for prioritization of failures of power transformer in risk assessment

SUMMARY The maintenance strategy of power transformer, which is determined by the operational condition, is very important to ensure safety for power system. But there exists prevalently the problem of lacking theoretical basis in preventive maintenance strategy to power transformer at present. Failure mode and effects analysis (FMEA) is a methodology for the analysis of potential failure modes within a system and has been extensively utilized for examining potential failures of power transformer. The critical issue of FMEA is the determination of risk priorities of potential failure modes. In order to provide the basis for risk assessment and preventive maintenance decision making, this work proposes the FMEA based on cloud model for prioritizing failure modes, which can combine randomicity with ambiguity and realize the transform between qualitative evaluation and quantitative numerical value, intending to overcome limitations of traditional FMEA. Two numerical examples are utilized to illustrate the potential applications of the proposed FMEA and the detailed computational process of the risk priority number based on cloud model. Copyright © 2012 John Wiley & Sons, Ltd.