A new life-cycle risk map (LCRM) for developing maintenance strategies for transmission equipment

The progress of aging of transmission equipment is becoming a crucial issue in Japan, and adequate maintenance strategies need to be developed in order to use existing equipment efficiently. In this paper, we propose the concept of a life-cycle risk map (LCRM) which shows the transition of aging risk of equipment from its installation to replacement, under a specific maintenance strategy that consider cost. The risk is evaluated based on expected energy not supplied (EENS) and the cost is represented by the economic lifetime when the annual average cost becomes a minimum. Using an acceptable level of aging risk, the optimal timing and cost of overhaul are determined. Numerical examples using a model system are shown and the potential applications of LCRM are also discussed.