Protection of transmission systems using transient polarity comparison technique

This paper presents the extended study on the application of new directional comparison technique for the protection of teed circuits. The technique relies on the detection of fault generated transient current signals. Comparison between the polarities of the captured current transient signals from the CT outputs at each end of the protected teed circuit will determine whether or not a fault is inside the protected zone. Simulation studies have been implemented by EMTP software for a 400 kV teed-connection power transmission system. Results show that the scheme is able to give correctly response for the protection of teed circuits, and it is insensitive to fault type, fault position, fault path resistance and fault inception angle.