This study describes the setting of distance protection for quadrilateral distance relay for double circuit lines which work at Extra High Voltage (EHV) by using (MATLAB SIMULINK) to simulate the three phase faults and states of earth faults for operation at different conditions taking into consideration the factors which effect on the measured impedance by relay especially the effect of zero mutual reactance to achieve the best setting.
The results proved that the setting with earth fault is the same as with phase fault. Also the change of setting factor causes undetermining of the fault location accurately. Also the results proved that the effect of intermediate station causes under reach and the reactance setting for backup zones tend to match among the different operation states.
Keywords: Protection, Distance, Relay, Setting.