An accurate unsynchronized fault location method on practically transposed transmission lines with closed-form solutions

This paper proposes an unsynchronized two-terminal fault location method on three phase practically transposed transmission lines. Compared to the existing fault location methods, the proposed method considers the asymmetry of the practically transposed transmission lines during the fault in practice. First, the proposed method constructs the practically transposed transmission lines by connecting three untransposed transmission line sections. For each section, the fully distributed parameters line model is adopted to ensure the modeling accuracy. According to the physical laws that the line should obey, the unsynchronized angle is estimated with analytical formulation before the fault. Next, the closed-form solutions of fault location are derived for different fault events, to avoid the risks of unconvergence using the iterative algorithms. In the numerical experiments, the proposed method shows higher accuracy of fault location than the existing fault location methods, regardless of fault types, locations and impedances. The proposed method also demonstrates robustness against various unsynchronized angles, loading conditions, measurement noises and line lengths.