Laboratory Setup for Ageing of New Environmentally Friendly Insulation Gases

In the last few years, several new gases have been identified and have become commercially available as possible environmentally friendly candidates to replace SF6 in electric power applications. However, long-term performance of these new gases is not fully known yet. This paper presents a laboratory test setup designed and built to study the effect of ageing due to electric arc on the long-term dielectric performance of the new insulation gases. The test setup has provision to expose the insulation gas to arcs like that experienced in a GIS during regular operation. To age the investigated gases to a level comparable to that in actual scenarios, energy dissipation in the arc in a typical medium voltage load break switch and 145 kV circuit breaker is calculated. Total energy dissipation within the arc channel is accordingly controlled in the proposed setup. By measuring the breakdown strength prior to and after the ageing, it is possible to investigate the long-term dielectric performance of the new gases.