Practical Test of Power Swing Blocking Relay

The main protection of transmission lines against electrical faults is the distance relay. According to the feature of this relays, which detect faults by utilizing the impedance of the line, they are susceptible to maloperation during power swing, which cause significant changes in the line impedance. The function of the power swing blocking is to detect impedance swings and block the distance relay to prevent its operation when it occurs.In this paper, various kinds of power swings consisting of stable and unstable swings and their features are explained first. Then, by using the simulation part of AMPro software, the power swing parameters are defined and the AMT205 test set is used to perform the tests. The results show that the relay under test detects power swing properly in both types.