A new method to prevent distance protection from operating due to power swing

A power swing may cause unwanted tripping of the distance protection. The power swing blocking is a function commonly used to prevent the distance protection from operating during power swing. When a distance relay is blocked, it cannot react to faults anymore. This paper proposes a new method to prevent this protection from operating during power swing condition when no fault occurs. In this method, swings are removed from the voltage and current signals, using (d-q) frame, and then these signals are used in the impedance calculation of the distance relay. So, the distance protection is not blocked and can trip when a fault occurs. Simulation results are presented for a typical system using PSCAD software.