Document Type : Research paper


Department of Electrical Engineering, Babol University of Technology, Babol, Iran


Generally, the failure rate and the repair time of system components are constant parameters in reliability assessment of electric distribution systems. A failure of component is resulted from failing in the operation or overloading. In addition, there exist cases where, the repair times of components are small and tolerable from customer point of view. Thus, tolerable repair times may be overlooked in the reliability evaluation of distribution systems. Therefore, by omitting the tolerable failures, reliability indices that are more reasonable, will be gained. In this paper, impacts of omitting customer tolerable repair time on electric distribution system reliability are studied. A simple model of circuit breaker, which differs from other components, is included. Monte Carlo simulation method is used for calculating reliability indices. A meshed distribution system is selected as a test system and simulations are performed and analyzed. Simulation results show that unavailability of load points are decreased resulting from omitting sustainable repair time, and also, it is required to include breaker model in distribution reliability evaluation.