A New Approach for Calculating Settings of Distance Relays Considering Mutual Coupling Effect

This paper proposes a new systematic approach for calculating settings of all zones of ground distance relays when mutual coupling effect is considered. The proposed zone 1 setting calculation method is based on the apparent impedance seen by the ground distance relays when faults are simulated on the assumed reach of zone 1. Also, it presents a method for calculating zone 2 and zone 3 settings based on the composite current assistance parameter and apparent impedance in the paper. It is shown that the proposed systematic method guarantees the coverage of zone 1 and increases the sensitivity and accuracy of zone 2 and zone 3 settings