Accurate fault location algorithm for parallel transmission lines using one-terminal current

Based on distributed parameter model, an accurate fault location algorithm for parallel transmission lines is described. Only using one-terminal current, shunt capacitance and complicated mutual coupling are taken into consideration in the algorithm. Common components and differential components are introduced into the algorithm to decouple mutual electromagnetic effect between circuits. Because the differential component network is just constituted by parallel transmission lines and its terminal voltages are zero, voltage distribution along differential component network can be calculated by current only. According to the boundary conditions of fault point and the transmission line parameters difference between positive sequence and zero sequence of differential component network, the equation of fault location can be founded. Theoretically, the proposed algorithm is independent of source impedance, fault resistance, shunt capacitance, and mutual coupling between lines. Since voltages are not be used in the algorithm, the measurement error of PT and CT will not affect on location accuracy. Computer simulation results using ATP show that the algorithm obtains high accuracy, and the maximal error is less than 0.15%.