For many decades sulfur-hexafluoride (SF6) has been used as insulating gas with good arc-extinction properties in gas-insulated metal-enclosed switchgear (GIS) and circuit breakers. Presently, the high global warming potential (GWP) of SF6 is motivating a worldwide search for environmentally friendly alternatives. Promising alternative gases with dielectric properties comparable to SF6 have a high dew point, and can be used in GIS as gas mixtures together with carrier gases only. As a precondition for their practical use, characteristic properties of alternative gases and their mixtures have to be examined. The focus of the research project with the new insulating gases is on the insulating capacity of different electrode arrangements with different gas mixtures relevant for high voltage application, the influence of gas liquefaction and the modeling of discharge development.
For further information, please contact: Michael Peiß, M.Sc.
Eco-friendly, fluorine-free basic technologies are being investigated for the transmission grid, i.e. for rated voltages of the switching devices and switchgear used from 420 kV. The basis for this is the use of climate-neutral insulating gases (e.g. synthetic air) in conjunction with vacuum interrupters as power switching elements. This requires considerable adjustments to the design of the switchgear and technological approaches to insulation concepts that are adapted to the properties of the alternative gas in question.