Systematic Study of Ultra-High-Speed Transient Based Protection for EHV/UHV Transmission Line

On the basis of effective extraction and utilization of transient fault information, this paper presents a whole scheme of ultra- high-speed transient based protection for EHV/UHV transmission lines, which consists of the main protection, the auxiliary protection and related protection elements. All protection elements are introduced, including starting element, directional element, boundary element, lightning disturbance identification (LDI), faulty phase selection (FPS) and switching-into-fault identification (SFI). And the logical relation among all protection elements is also illustrated in detail. Under various fault situations, utilizing a number of EMTP simulation data, the performance of this transient based protection scheme is investigated, and the factors influencing on protection performance are analyzed carefully. Theoretical analysis and testing results show the proposed protection scheme is feasible and ultra-high-speed.