Substation Reliability Evaluation Considering the Failure Events

In this paper, bus and breaker structures of typical two substations were modelled by graph circuit to evaluate each reliability considering the various failure events and compare them each other. Passive failure event, active failure events, breaker stuck conditions and overlapping failure events in substation were conceptually explained and the reliability equations were presented to calculate the failure rate, repair rate and unavailability of each failure events. Also, deduction algorithms were implemented as a software programming to find the minimal cut sets for passive failure events and active minimal cut sets for active failure events. In the case study, reliability indices of each failure events and entire reliability indices (failure rate, annual outage time and MTTR) of typical two substations were calculated and quantitatively compared.