Research on Ultra-High-Speed Directional Relay of EHV/UHV Transmission Lines Using Wavelet Transform

Abstract:- This paper proposes a novel ultra-high-speed directional relay using the wavelet transform. Two relay signals indicating traveling direction are composed of fault-induced voltage and current waves propagating along EHV/UHV transmission lines. Wavelet transform technique is employed to extract transient components from the relaying signals, and represent the transient component magnitude with wavelet transform spectrum energy (WTSE). Fault direction is determined by comparing the transient component WTSE of the two relaying signals during a post-fault period. A large number of various fault scenarios have been simulated with EMTP to evaluate the validity and reliability of the proposed scheme