Precise Analysis of power swing effects on distance relay zones

Fault occurrence and abnormal system condition are inevitable in power systems. To reduce the results of the mentioned conditions such damaged equipment or in the worst case, power system instability, it is required to do necessary tasks. One of the most important protection methods for this goal is distance protection. Due to mal-operation of distance relay, power system might be damaged. This paper briefly investigates the concept of the distance relay and then, power swing equations of power system are studied. Finally, the effect of power swing on distance relay zones are investigated using EMTDC software. Extended simulations were performed using different cases in different protection zones.