Earthing switch for metal-clad high-voltage switch gear insulated with compressed gas

摘要

An earthing switch may be used for a metal-clad, high-voltage switchgear insulated with compressed gas. The mobile earthing contact is arranged so as to be insulated from the earthed cladding for measuring purposes. The insulation arrangement of the earthing contact is bypassed by an electrical connection, preferably outside of the cladding to earth the switching device. The electrical connection is disconnected when the earthing contact is connected in the closed position to a measuring device. An additional contact arrangement is provided that electrically bypasses the insulation arrangement and connects the mobile earthing contact to the earthed cladding when the switch is between the closed and open positions. This prevents surges resulting from pre-arcing on the insulation arrangement and possible damage to measuring instruments that may be connected to the earthing switches.