A Fault Location Algorithm Based on Circuit Analysis for Untransposed Parallel Transmission Lines

This paper proposes a fault-location algorithm for ultra-high-voltage untransposed parallel transmission lines that only use the voltages and currents at the local end. The proposed algorithm uses the voltage equation for the faulted phase of the faulted line. The equation contains the fault distance, fault resistance, and fault current. To obtain the fault current, Kirchhoff's voltage law is applied on the loops of three phases consisting of the faulted line and the adjacent parallel line. The fault current can be represented in terms of the fault distance. Inserting the fault current into the voltage equation results in an equation that contains only two parameters (i.e., the fault distance and fault resistance). The fault distance is estimated by solving the equation. Test results indicated that the algorithm accurately estimates the fault distance regardless of the fault resistance and mutual coupling effects.