Performance Analysis of a Distance Relay for Zone Identification

Distance relay is a widely used protective scheme for transmission line protection due to their high speed fault clearance. A distance relay estimates the distance of the fault by calculating the impedance by measuring the current and voltage at the relay point and compares the result with a given threshold, which determines the correct zone of protection. This paper presents a distance relay model designed and modelled using MATLAB / SIMULINK which identifies the correct zone of the fault. The model is tested for various fault conditions. The results show that the relay is able to identify the fault zone and isolate the fault line as per the relay settings.