Power-Swing Detection Using Moving Window Averaging of Current Signals

Power-swing blocking (PSB) function is necessary for the distance relay to avoid unwanted tripping of the transmission line. A power swing detection technique is proposed in this paper using a moving window averaging technique. The moving average of modulated current signal during power swing varies periodically whereas on inception of a fault, it remains either in positive or negative half. Using this property, two indices are calculated based on sign and time criteria of the moving average in order to distinguish the power swing from the balanced fault. The method is tested for numerous swing and fault conditions of a two-area four machine and WSCC 9-bus systems and compared with conventional methods.