Locating a fault in double-circuit transmission lines is a challenging task due to the mutual coupling effects between adjacent circuits of the line. Also, performance of impedance-based fault location schemes for double-circuit lines is adversely affected by fault resistance. Accurate fault location in double-circuit lines can be achieved if fault location schemes utilize reliable communication links. However, the communication links are not available or enabled in all transmission lines. To overcome such difficulty in fault location in double-circuit lines, a new fault location scheme is proposed for double-circuit transmission lines by using voltages and currents data extracted from single-end of the line. Only the negative-sequence current and voltage phasors during the fault are processed for calculating the fault location. The proposed fault location formula is derived by applying the Kirchhoff s voltage law around the parallel circuits and shunt capacitances loops. Obtained formula is applicable for all types of unbalanced faults and accordingly classification of fault types and phase selection are not required. The proposed scheme is immune to the fault resistance and insensitive to mutual coupling effects. Evaluation results verify that the accuracy of the proposed algorithm is very high under various fault resistances, fault locations, and fault types.
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