Study of an Assessment Method for the Reliability of Tap-changers in Power Transformer Based on Fault-Tree Analysis

Based on the further analysis of typical failure modes and influences of tap-changers in power transformer, the fault-tree of tap-changers is set up by using fault-tree analysis(FTA) techniques and the assessment method for the reliability of tap-changers, combined with the index of the importance and the method of Improved Analytic Hierarchy Process(IAHP), is put forward. The assessment examples show the method can deduct the failure modes of tap-changers clearly, meanwhile, find out the weaknesses in time during the operation and get better assessment results.