Hybrid Transmission Line Fault Location Method Using Time Difference-Wave Velocity Mapping Characteristics with Double-Ended Traveling Waves

With the increasing adoption of hybrid cable-overhead lines in power systems, conventional fault location methods based on uniform line parameters face challenges in accurately identifying fault sections and determining precise fault locations. This is primarily due to the inconsistent wave propagation velocities in overhead lines and cables. To address this issue, this paper proposes a double-ended traveling-wave fault location method specifically designed for hybrid cable-overhead transmission lines. The method utilizes the unique correspondence between the time difference of fault-induced traveling waves arriving at sensors on both ends and the wave velocity in the hybrid line during faults to achieve accurate fault section identification and location. A detailed model of the hybrid cable-overhead line was developed, and simulation tests were conducted by introducing faults both inside and outside the cable section. A comprehensive database mapping the relationship between double-ended traveling wave time differences and corresponding wave velocities was established to validate the effectiveness of the proposed method. The results demonstrate that this approach can effectively distinguish between faults occurring inside and outside the cable section, while enabling precise location of faults within the cable segment. This method significantly reduces fault detection time, thereby playing a crucial role in improving power supply restoration efficiency and offering substantial practical significance for modern power systems.