A New Fault Location Method for Partial Coupling Double-Circuit Untransposed Transmission Line with Shared Tower and Different Voltages

This paper presents a new fault location method for partial coupling double-circuit untransposed transmission lines with shared tower and different voltages. The synchronized voltages and currents at each line terminal are needed to obtain the fault location. The proposed method is formulated based on theory of transmission lines and Taylor series expansion for distributed parameter line model. The mutual coupling between all phases and the untransposition of the line is considered to obtain accurate results. The faulted phases are recognized using Kirchhoff's current law (KCL) and the locations of all fault types including inter-circuit faults can be determined. The power system is modeled on DIgSILENT Power Factory software, and the fault location calculations are implemented using MATLAB. The performance of the proposed method is checked under diverse values of fault types, fault resistances, and fault locations. The effect of synchrophasors errors, measurement errors, varying soil resistivity, errors in line parameters, and complex fault impedance is also verified. The simulation results prove that the proposed method achieves better performance for all test cases.