This paper presents a novel fault location algorithm for a distance relay of a transmission line. Under the assumption that the source voltages and impedances of both ends are not changed before and after a fault, the fault current and the voltage of the terminal end are estimated including the loading condition. Then, the fault location expression, independent of the fault resistance, is derived using these voltages and currents through a loop analysis, in the manner that the in-feed effect
of the terminal end is eliminated. The suggested algorithm is applied to a typical transmission line to show its effectiveness.
