Transient Response of Grounding System in Underground GIS Substation

Abstract

Transient grounding impedance of a gas-insulated switchgear (GIS) substation were investigated through measurements on a commercial 300kV underground substation. From the results, the transient impedance of the grounding grid was clarified. The attenuation factor of the propagation line composed of the outer surface of the GIS tank and the concrete floor was also evaluated. Furthermore, the validity of EMTP analysis on the surge phenomena in the GIS grounding system was confirmed.