1. Field of the Invention
The invention is based on an isolator for a metal-encapsulated, gas-insulated, high-voltage switching installation.
2. Discussion of Background
In this case, the invention makes reference to a prior art as a result, for example, from the Laid-Open Specification DE-A1-42 10 545. This publication describes an isolator for a metal-encapsulated, gas-insulated, high-voltage switching insulation, having two switching pieces which are arranged in the metal encapsulation, which is filled with insulating gas, and can make contact with one another, or can be isolated from one another, along an axis, each having a pre-arcing contact, which is in the form of a pin, extends axially and is constructed as an overtravel contact in the case of one of the two switching pieces, and having a stationary contact which coaxially surrounds the pre-arcing contact of a stationary one of the two switching pieces, as well as having a moving contact which is provided on a moving one of the two switching pieces and, in the connected position, forms a continuous current path with the stationary contact.
This isolator has a comparatively large axial extent. This is a result of the fact that both the actual isolating gap of the isolator and all the moving parts lie on one axis, which coincides with the longitudinal axis of the current-carrying active parts of the gas-insulated switching installation. In addition, as a result of the overtravel contact, structural elements were introduced into the moving switching piece, which have a considerable extent in the axial direction and must be shielded in high-voltage terms. This leads to a not inconsiderable enlargement in the axial direction of the isolating switch geometry, which is already intended to form a significant part as a result of the isolation distance of the open isolating gap.