Reliability assessment of power distribution systems using tripping rate of protective devices

This paper presents a method of reliability assessment of power distribution systems by using tripping rates which are calculated from uptimes of the downstream area of each installed protective device. This method is demonstrated through case studies including of real power distribution circuits in Thailand based on outage database recorded from 2004 to 2010. From case studies, reliability indices calculated from the tripping rate yield percentage errors of 24.66 and 30.44 on SAIFI and SAIDI respectively. This method is found more suitable for power utilities which have operation records of protective devices, but lacking of failure data by component that requires huge effort to collect plus a complex database system.