A new directional comparison technique for the protection of teed transmission circuits

This paper presents the extended study and application of a new directional comparison technique for the protection of teed circuits. When a fault occurs on a teed system, comparison between the polarities detected at each end of the protected circuit will determine whether a fault is inside or outside the protected zone. In contrast to previous research based on the measurement of fault generated power frequency signals and initiated travelling waves, this technique pays more attention to the fault generated signals under arcing fault conditions and their associated high frequency signals. For an external fault it is seen that it is possible to determine on what line of the external system the fault has occurred. The faulted responses are examined with respect to various system and fault conditions. With this approach, the problem of low fault inception angle is effectively solved since the fault arc signals vary little with inception angle