Performance evaluation of fault component distance relay for protection of lines compensated by UPFC

In this paper the performance of a new fault component impedance distance relay based on voltage amplitude comparison is evaluated and its capability to mitigate the impact of UPFC on the apparent impedance measured by the relay is analyzed. As the impact of shunt branch of UPFC on the apparent impedance is mainly due to the fault resistance; thereby the proposed relay can perform better than the conventional distance relays. The behavior of the proposed relay is evaluated for different fault locations, fault resistances and fault types. The relay operation boundaries for different fault locations and fault resistances are derived for comparison.