High Speed Directional Comparison Protection of Transmission Lines

Improvements of system stability and reduction in the effects of shunt type faults in transmission and bulk systems on sensitive industrial loads can be achieved through the development of protection relays with sub-cycle operating times for faults anywhere on the transmisson line. State-of-the-art communications methods and advanced algorithms allow the implementation of such solutions. The paper discusses in detail a directional comparison protection system based on superimposed components directional detection. A new relay-to-relay communications protocol meets the requirements of different schemes and at the same time ensures fast operating times over different communications channels.