A new directional relay for distribution network protection using transient comparison technique

This paper presents a new protection technique for the protection of distribution system networks. In the protection system, the proposed relays are installed at each substation busbar of a distribution network and are responsible for the detection of the fault direction relative to the busbar. Each relay containing transient detection and comparison units is interfaced to the CTs on each of the incoming and outgoing lines from that busbar. The transient signals captured from each line are filtered and then integrated based on a small moving window function to obtain their spectral energies. The level of the energy entering the busbar is then compared with that leaving it, to ascertain the direction of the fault with respect to the busbar at which the relay is installed