Transient Ground Potential Rise in Gas-Insulated Substations - Problem Identification and Mitigation

Transient ground potential rise, a phenomenon of 10-100 kV potentials with up to 10 ¿s duration on the grounded enclosures of gas-insulated substations (GIS), may cause concern for personnel safety and problems for protection and control circuitry. This paper summarizes the results of a research programme conducted for the Canadian Electrical Association [1] and is intended to serve utilities as a practical introduction to this topic. The transient potentials are derived from enclosure configuration using analytical calculations and digital simulations. Modified operating practices, changes in GIS configuration and use of shielding methods may be considered for mitigating the effects of these potentials.