long term cost effective preventive maintenance scheduling

preventive maintenance scheduling of generating units is addressed as a long-term scheduling in power system studies aiming to increase the reliability incorporating cost reduction. it consists of knowing which generating units should be shut down for regular safety inspection. in this paper, a new formulation of preventive maintenance scheduling associated with cost reduction index (cri) is presented. mainly, the purpose of the maintenance problem is minimizing the operation as well as maintenance costs over a specified time horizon. cri is introduced in such a way to reduce the operation cost along the scheduling time while determining the most proper maintenance scheme. the proposed framework is structured as a mixed integer linear programming (milp) and solved using cplex solver. the suggested model is applied to a standard ieee reliability test system (rts) and the promising results show the effectiveness of the proffered model.