Measured impedance by distance relay in inter phase faults considering double equivalent model for line capacitance

This paper investigates the measured impedance at the relaying point considering the transmission line capacitance by utilizing a double equivalent model, in the case of inter phase, phase to phase and three phase, faults. The distance relay ideal tripping characteristic is presented and investigated. The measured impedance at the relaying point and the ideal tripping characteristic are compared with those in the case of neglecting the line capacitance. In the case of zero fault resistance, the deviation of the measured impedance from its actual value, caused by the line capacitance, is highlighted.