A New Location Method of Faulty Segment for Hybrid Transmission Lines Based on Transient Travelling Wave Analysis

Abstract

Abstract The paper proposes a new location method of faulty segment for hybrid transmission lines combined with overhead line and cable. Conventional location method of faulty segment identify faulty segment through position calculation of fault point. However, affected by error, the fault at cable-overhead line joint is hard to be identified. In this approach, faulty segment is identified through characteristics comparison of transient travelling wave under different condition. Compared with situation that fault occurs on overhead line, if fault occurs in cable, there is an additional impedance discontinuity in cable. Thus, the amplitude and wave of various reflected wave will change significantly. The proposed method extracts various reflected waves based on time windows and polarity. It makes use of the relative amplitude and time difference between first travelling wave and secondary reflected wave of cable-overhead line joint as criterion of faulty segment location. To verify its effectiveness, fault simulations based on EMTDC are performed; the simulation results reveal that the proposed method can correctly identify the faulty segment for hybrid transmission lines.