A Travelling Wave-Based Fault Location Method for Hybrid Three-Terminal Circuits

In this paper, a travelling wave-based fault location method for hybrid three-terminal transmission systems, including offshore cables and an onshore overhead line, is proposed. Such systems are utilized for offshore wind farms interconnection. The receiving ends are equipped with optical transient recorders as well as Global Positioning System (GPS) signal receivers to measure synchronized transient voltages. Discrete Wavelet Transform (DWT) is utilized to extract transient information from the measured voltages. The arrival times of travelling waves at the receiving ends obtained using voltage wavelet transformation coefficient squared (WTC2) are utilized for faulty segment identification and fault location. Transient simulations are carried out using EMTP-RV software and MATLAB Wavelet Toolbox is utilized for post-fault analysis. The simulation results are presented to validate the performance of the proposed method.