The Development of a Novel Spacer of GIS With VFTO Tolerance

Metal-enclosed gas-insulated switchgear (GIS) offers the advantages of a small footprint, high reliability, strong safety features, and convenient installation. As such, it has found widespread use in a variety of applications. However, the operation of the GIS isolation switch when opening and closing an unloaded bus can generate the very fast transient overvoltage (VFTO), which pose a significant threat to the stability of the GIS's internal insulation. To mitigate this influence, it is imperative to suppress the generation and propagation of VFTO and enhance the device's tolerance to it. In this article, we present a novel spacer with improved VFTO tolerance, achieved through material modification and structural design. The VFTO suppression capability of this new spacer was evaluated through simulations using EMTP and COMSOL software and subsequently validated experimentally. Compared to a conventional spacer, our new design demonstrated a reduction in voltage peak at the edge of the spacer by more than 10%, as well as an improvement in VFTO propagation suppression by more than 10%. This novel spacer effectively suppresses the propagation of VFTO and enhances its tolerance.