A new method for unit maintenance scheduling considering reliability and operation expense

Along with the rapid development of the industry, the load of the power system increases incredibly as well. Due to the concern of environmental protection, the building of the power plant is more difficult than ever before. This result will lead to insufficient spinning reserve that could not meet the requirement. Under this situation, it is important to build a unit maintenance scheduling considering system reliability as well as operational and maintaining expense. Therefore, a new formulation considering both reliability and cost reduction for maintenance scheduling is proposed in this paper. Because factors of spinning reserve, man crew for maintenance, operational period, line flow limitations, and operation and maintenance expense are concerned in this model, this formulation will become complicated and hard to solve. In order to solve this complicated formulation, this paper adopts the genetic algorithm combined with the simulated annealing method as a solution method. This new formulation can find a minimum cost for operation and maintenance under a condition of sufficient spinning reserve. In contrast, if the spinning reserve is tight, a compromising solution between reliability and cost can be obtained. In order to verify this algorithm, test results of a six-unit case and a Taiwan Power Company System are demonstrated in this paper.