Ground distance relaying algorithm for high resistance fault

This study proposes a new fault impedance estimation algorithm of phase-ground fault for ground distance relaying based on the negative-, zero- and comprehensive negative-zero-sequence current component. The principle is based on the assumption that fault path is purely resistive, and the phase angle of fault point voltage and fault path current is equal to construct the fault impedance estimating equations for ground distance relay, which can eliminate the effect of fault path resistance, load current and power swing. PSCAD software simulations show the accuracy of proposed algorithm.