An accurate fault location algorithm for double-circuit transmission systems

This paper describes an accurate fault location algorithm based on sequence current distribution meters for a double-circuit transmission system. The proposed method uses the voltage and current collected at only the local end of a single-circuit. This method is virtually independent of the fault resistance and the mutual coupling effect caused by the zero-sequence current of the adjacent parallel circuit and insensitive to the variation of source impedance. The fault distance is determined by solving the forth-order KVL (Kirchhoff´s voltage law) based distance equation. The zero-sequence current of adjacent circuit is estimated by using a zero-sequence current distribution factor and the zero-sequence current of the self-circuit. Thousands of fault simulations by EMTP have proved the accuracy and effectiveness of the proposed algorithm