Identification of a Best Algorihthm for Digital Distance Protection of Transmission Lines

The paper describes amethod for seeking out the best or optimal combination of digital distance relay and digital filter algorithm for transmission line protection. It is found that this best combination consists of a 3rd order recursive low pass filter algorithm and distance relay algorithm based on the solution of the differential equation representing the transmission line model. Typical relay transient operating characteristics on R-X co-ordinates are presented.