Life-cycle-cost evaluation of degradation diagnosis for cables

Life-cycle management combined with degradation diagnosis is useful for preventing an unexpected failure, extending service life of an electric power apparatus and minimizing life-cycle cost. In our previous paper, we proposed a method of life-cycle-cost evaluation based on TBM, and evaluated the economic effect of degradation diagnosis. To carry out reliable life cycle management, however, accurate data on the relation between extent of degradation and failure probability or remaining life as well as a well-established diagnostic method are necessary. Therefore, we have examined the influence of accuracy of the data used to determine the optimum diagnostic parameters and have evaluated how the life cycle cost is affected by the employment of inaccurate data. As a result, we have confirmed that the optimized diagnosis interval is influenced by change in failure probability, and the life cycle cost increases greatly when the inaccurate measured data give longer diagnostic interval and looser diagnostic criterion as the optimum diagnostic parameters.