Fault component reactance relay

A new power system distance relay is developed in this paper. The relay is based on two operation criteria: a current criterion; and a voltage criterion. Each uses the fault component as the operating quantity, and the relay reacts only on the reactance of the transmission line. So, it is a fault component reactance relay. During external faults, the two criteria are complementary to each other, i.e. at least one of them will not be satisfied; so no maloperation will occur. During internal faults, both criteria will be satisfied even if the fault resistance is high.