This book develops novel digital distance relaying schemes to eliminate the errors produced by the conventional digital distance relays while protecting power transmission lines against different types of faults. These include high resistance ground faults on single infeed transmission lines; high resistance ground faults on double infeed transmission lines; simultaneous open conductor and ground fault on double infeed transmission lines; inter-circuit faults on parallel transmission lines; simultaneous open conductor and ground fault on series compensated parallel transmission lines; inter-circuit faults on series compensated parallel transmission lines; and phase faults on series compensated double infeed transmission lines. This monograph also details suggestions for further work in the area of digital protection of transmission lines. The contents will be useful to academic as well as professional researchers working in transmission line protection.