Evaluation of fault analysis tool under power swing and out-of-step conditions

Several major blackouts were caused by distance relay mis-operation. Distance relay mis-operation may occur following a large disturbance in the system causing power swing and out-of-step conditions. If an on-line fault analysis tool is able to detect power swing or out-of-step conditions and indicate mis-operation of relays, the operator may be notified to switch back the healthy transmission lines tripped due to relay mis-operation. A new automated fault analysis tool comprising fault detection, classification and location has been developed and its performance under various power swing and out-of-step conditions is reported. The test results indicate that the fault analysis tool performs better than distance relay under power swing and out of-step conditions and can be used as a tool to verify distance relay operation in practical circumstances. The simulations have been performed using IEEE118 bus test system modeled in ATP software.