A condition-based maintenance approach to an optimal maintenance strategy considering equipment imperfect maintenance model

Power grid tries to maximize its profit by reducing generation cost, supply costs and operation costs while sustaining its required reliability. Developing maintenance strategies is one of the most effective methods. The condition-based maintenance approach is a key method in providing optimal maintenance strategies in theory. It considers the tradeoffs between the system maintenance risk and the potential system failure risk of system reliability losses. Since power grid contains a group of different kinds of equipments and the reliability of the electric equipments varies with time. One type of electrical equipment has different maintenance models because of their different failure modes and deterioration processes. A union method for equipment maintenance model and system condition-based maintenance model is proposed. The modified imperfect maintenance model-Kijima II model is selected for equipment maintenance model comparing with minimal repair and perfect maintenance through optimizing imperfect maintenance effect factor. In addition, a genetic algorithm is used to find the optimal maintenance strategies from possible maintenance scenarios. These optimal maintenance strategies have been tested on a HVDC link which is simplified into an equivalent serial and parallel system and an IEEE-RTS79 system. The results demonstrate the feasibility and validity of the proposed model.