Travelling Waves Based Fault Location Method for Overhead-Cable Hybrid Multi-Terminal Transmission Line

With the continuous construction and development of power grid, there are more and more multi-terminal lines with overhead-cable hybrid structure, and the conventional fault location method of single line has been difficult to achieve accurate location. This paper presents a novel fault location method based on the attenuation degree of traveling wave is proposed by analyzing the refraction and reflection of fault traveling wave in hybrid multi-terminal line. It uses the degree of attenuation caused by refraction in the process of traveling wave propagation to determine the fault branch, and then uses the time difference method to identify the fault line, and finally uses the two-terminal traveling wave (TW)-based fault location method to locate the fault. Simulations based on a typical 110kV multi-terminal hybrid line are used to test the proposed method. The results show that the error is less than 0.14km for the tested system, and the proposed method is suitable for multi-terminal mixed circuits with the similar structure.