Optimization on maintenance cycle for power plant equipment based on probabilistic risk assessment

Selection of a rational maintenance cycle is one of the main tasks to implement condition-based maintenance for power plant equipment, which can be achieved from reliability-centred maintenance (RCM) logical decision method. In this paper, a probabilistic risk assessment (PRA) technology is applied to RCM analysis on power plant equipment. The minimum maintenance risk cost is taken for an optimized objective to solve the optimum maintenance cycle. A method to calculate the maintenance risk cost through PRA technology is proposed after the technological process to determine the optimum maintenance cycle for power plant equipment is defined. The relationship between fault rate and maintenance activities including condition monitoring and preventive maintenance is comprehensively analyzed. Then an optimum model of maintenance risk cost is set up, and an overall maintenance strategy with optimum maintenance cycle is obtained through genetic algorithm (GA). Finally, the feed pump set of one 200MW turbine is regarded as an example of application for verification, and satisfactory results are got. As a result, the total maintenance cost based on the maintenance cycles through GA will be reduced greatly in comparison with the traditional approach.