Robustness Assessment of Life-Cycle-Management of CV Cables based on Degradation Diagnosis

Abstract

Life-cycle management based on the degradation diagnosis is useful for preventing an unexpected failure and extending service life of electric power apparatuses, minimizing life-cycle cost. In our previous study, we formulated a numerical model of life-cycle management based on time-based maintenance and condition-based maintenance. Then, we applied the model for evaluating the economic effect of degradation diagnosis of power cables, assuming that the maximum length of water tree as a replacement criterion can be measured nondestructively. To carry out reliable life cycle management, however, accurate data on the relation between extent of degradation and failure probability or remaining life are necessary. In this study, we examine the influence of accuracy of the data used to determine the optimum diagnostic parameters and evaluate how the life-cycle cost is affected by the employment of inaccurate data. The results show that the condition-based maintenance with degradation diagnosis can be less subject to the accuracy of the back data and is possible to realize the reliable life-cycle management.

Review of recent research towards power cable life cycle management

“…Understanding and accurately modelling the ageing processes of cable assets under service conditions, predicting reliability and future failure rate is useful to identify appropriate actions for acutely degraded individual assets or components at the lowest LCC. In [79, 80], the LCC was calculated in three steps: (i) data processing, historical data such as water tree length, breakdown voltage and failure probability are involved and mathematical relation among them are established and used in the next step; (ii) calculation of failure probability and replacement; and (iii) calculation of LCC based on different diagnosis conditions [79] and various diagnosis rules [80].…”