Application of fault current limiter to limit distributed generation effect on distance relay coordination

For the protection of transmission lines distance relays are used up to a great extent. Here distance relays are used for relay coordination process. This paper considers a MHO relay characteristics, zone settings and zone discrimination time as the parameters of distance relays. The approach is used to figure out distance relay coordination bearing distributed generation in a distributed system. The impact of distributed generator in a power distributed system varies the relay settings of the system. So on implementing fault current limiter reduces the distributed generator fault current and restores the archetype relay coordination without varying the relay settings. The methodology of selecting the fault current limiter and its typical value is illustrated. A sample distributed network with and without distributed generation is modeled and simulation results for the impact of distributed generation on protection system coordination are presented and discussed here.