Adaptive Distance Protection to Prevent False Relay Tripping during Power Swing

The existing distance relay is accommodated with starting function to detect short-circuits in power system. However, this function proves vulnerable to distance relay operation as it could falsely send a tripping signal during power swing. Hence, it is important to introduce an adaptive concept to the distance protection to prevent such false tripping. This paper presents a simple and effective adaptive protection algorithm for power swing prevention based on Under Impedance Fault Detector (UIFD) characteristics, in which capable to identify the power swing condition and adjusting the relay setting accordingly to avoid system mal-operation.