Design and Simulation of Three Zones Distance Protection Scheme

This work describes the protection mechanism of transmission line at fault. Transmission line is divided into three zones and it is also provided by a backup protection MATLAB simulation was used to represent the three steps protection under single line to ground fault in different zones. Distance Relay was used to measure impedance as a part of power system, when the fault impedance dropped below the predetermined value a trip signal will transmit to the circuit breaker. MATLAB simulation is used to simulate the proposed model for three zones. The results illustrated the fault impedance at each zone and finally it has been concluded that the lower impedance is obtained at zone B (27.33 ?) in phase T.