Abstract
•A system with prescheduled standby mode transfers is considered.•A product storage is used to reduce system downtime during its mission.•An algorithm for evaluating the downtime is developed.•Mode transfer schedule optimization problem is formulated and solved.•Influence of the storage on the optimal schedule is demonstrated.
Mode transfers have attracted attention from the standby system community as they can effectively reduce system downtime. However, the existing models are not applicable to standby systems with product storage. This paper advances the state of the art by modeling mode transfers in 1-out-of-N standby systems with storage, which saves surplus products generated during the system operation and these products may subsequently be used to supply the system demand. When the system demand cannot be supplied by the operating element or from the storage, the downtime incurs. Moreover, the length of the downtime may be affected by the mode transfer schedule of different elements. Thus, it is significant to determine the optimal mode transfer schedule (MTS) minimizing the expected mission downtime (EMD). To solve this optimization problem, a new numerical algorithm is put forward to evaluate the EMD of the considered standby system under a given MTS. The genetic algorithm is then implemented to solve the proposed optimal MTS problem. A detailed case study of a power generation system with five generators and a storage is conducted to demonstrate the proposed model and methodology. Effects of several parameters and their interactions on the EMD and optimization solutions are also demonstrated.