A new approach of Mho distance relay for Transmission line protection

Abstract

The protection of transmission line is one of the important requirements of the modern power system network to protect the equipment and persons work on it. distance relay is one of the relays used to protect the transmission line where the input to the fuzzy based distance relay are the resistance and reactance of transmission line from relay to the fault location. These were calculated from the measured voltage and current. Mho type distance relay is proposed by using fuzzy logic methodology to protect the transmission line and to defeat under and over-reach problems. MATLAB-Simulink is used to model the relay and the test network, where the fault type is detected and four zones of fault location are provided, the trip signal is delayed according to the zone number. Also the (R-JX) plain is used to show the zone of fault in a simplified manner.