ABSTRACT
The paper presents modeling and testing of computer distance relay using MATLAB/PSCAD.
The relay has been tested in 345 kV parallel overhead transmission lines that include the
mutual coupling. The paper is demonstrating the relay's capability to detect the fault at
different zones, producing a tripping output for different fault conditions. The concepts of
traditional distance relaying were used and three zones were defined for the transmission
system to be protected by the relay. Different fault types were simulated occurring at distinct
locations within the transmission system. The computer relay is developed using MATLAB
and the transmission line model is implemented using EMTDC / PSCAD.