High speed grounding switches (HSGS) in GIS

The primary purpose of these switches is identical to that of grounding switches in air - insulated substations and non - fault - initiating grounding switches in Gas - Insulated Switchgear (GIS).

High - Speed Grounding Switches (HSGS) possess an additional feature: they can close an energized conductor, creating a short - circuit while sustaining minimal damage to either the switch itself or its enclosure. HSGS are utilized to ground various active components within a substation, including transmission lines, transformer banks, and main buses. In certain GIS facilities, HSGS are employed to trigger protective relay functions. Notably, they are generally not used for grounding circuit breakers or voltage transformers.

HSGS are engineered and tested to interrupt electrostatically - induced capacitive currents and electromagnetically - induced inductive currents that occur in de - energized transmission lines running parallel to and in close proximity to energized transmission lines. Additionally, they can eliminate DC trapped charges on a transmission line.

HSGS typically feature motor - operated mechanisms with spring - assist to facilitate the rapid opening and closing of the switchblade. They usually employ the same techniques as disconnect switches for determining the switch position. The figure depicts a HSGS connected to a bus.