Review of assessment methods for economic feasibility of insulation diagnosis

This paper introduces three existing assessment methods and their evaluation results, and discusses the feasibility and accuracy of each method. It is argued that the assessment method based on residual lifetime is difficult for practical application. Moreover, the reliability of the life-cycle-cost assessment based on accelerating degradation experiment is related to the accurate evaluation on the annual failure probability and distribution of the measurement parameter in the accelerating-degradation experiment. As to the method based on actual data investigation, accurate assessment will be based on the comparative investigations on a large number of apparatus with diagnosis and those without diagnosis. Because the existing evaluation results suggest that present diagnosis method may not be feasible in economics, fundamental, researches are still necessary to understand the aging mechanism, so as to develop diagnosis method and improve their efficiency.