Smart Testing of Power Swing Detection in IEDS

Power swing which is primarily caused by sudden addition or removal of load in a transmission line, consequent to an enormous interruption in power system, which if not blocked, could cause wrong operation to the distance relay which may lead to tripping the healthy part of the transmission line. In the absence of power swing function it may result in severe damage to the machines or cascading tripping in the grid resulting in blackouts. To prevent such scenarios, intelligent electronic devices (IEDs) have power swing block (PSB) detection and trip logics incorporated with distance schemes. This logic provides severe challenges to T & C engineers, where the conventional methods of using several states and multiple configuration steps while testing the IEDs complicates the process of testing. Further, the variations in logics due to manufacturer specific algorithm add to the complications. To address such complications, a new testing philosophy has been developed in, where PSB, PSD and PST functionality testing methodology and detailed discussion on the oscillography file is explained in this paper.