A Risk-Based Decision Approach for Maintenance Scheduling Strategies for Transmission System Equipment

Cost-effective maintenance scheduling of power system equipment is critical, especially with present economic scenario of power industry. Apart from long-term maintenance policy, asset planners need to come up with revised short term maintenance strategies mainly due to the shrinking budget allocations for various reasons. The problem may be formulated as follows: if it is the same availability of labor crews, and labor hours, and the given budget is constrained, how the maintenance decisions needs to be revised. The problem is particularly prominent if one needs to assign maintenance tasks for part of a system, say a substation with few circuit breakers and transformers. A risk-based decision approach is proposed which suits best this kind of situation. In this approach, the classic definition of 'risk' term is adopted, which is the product of event probability and event consequence. Risk based approaches have been proposed earlier, but this paper differs in the way the 'event probability' and 'consequences' are defined and calculated. Condition monitoring devices can be used to get informed about the equipment condition up to date, which plays major role in this approach. The 'event probability' is updated after a specified maintenance action and risk is recalculated, and the difference is the direct result of that maintenance activity. The proposed approach is implemented on a set of circuit breakers in a substation.