Research On Reliability Of Transmission Line Protection In Intelligent Substation Based On Minimal Path Set

This paper studied transmission line protection system of intelligent substation and its reliability based on minimal path set.It analyzed relay protection system mode of intelligent substation.Then,it modeled the reliability block diagram including synchronous clock system,SV transmission system,GOOSE transmission system.It proposed searching node method to search minimal path set and adopted disjointing calculation to simplify minimal path set.At last,it adopted local approach and global approach to calculate reliability model of transmission line protection system.Lastly,it analyzed the protection configuration scheme of 220 kV transmission line protection and 110 kV transmission line protection in a 220 kV station in a power supply company.Then it modeled the reliability block diagram,combing local approach,global approach and disjointing calculation to calculate its reliability based on minimal path set.The result showed that double set of protection was more reliable than a single set of protection,adopting SV directly and transmitting GOOSE directly was more reliable than networking mode.Important transmission line needed a more reliable protection system and real time reliability calculation can guide repair work.