DIELECTRIC STRENGTH OF ENVIRONMENTAL-FRIENDLY GAS MIXTURES OF C₄H₂F₆/CO₂ AND C₄H₂F₆/AIR

SF₆ gas is widely used in electric power apparatus as an insulation and arc-quenching medium. However, SF₆ gas has a high greenhouse effect. There are many investigations focusing on searching for environmentally friendly insulation gases which can achieve equivalent insulation strength with SF₆, meanwhile, reduce global warming potential (GWP) apparently. C₄H₂F₆ is a novel, chemically stable, non-toxic and non-flammable gas which has a low GWP of 18, a zero Ozone Depletion Potential (ODP), a boiling point of 7.5℃ and a critical temperature of 137.7℃. In this paper, we set up an experiment platform to study the dielectric strength of C₄H₂F₆/CO₂ and C₄H₂F₆/Air under DC voltage. Experiments in the plate electrode were done in 5mm gap distances, different pressures and gas ratios of C₄H₂F₆/CO₂ and C₄H₂F₆/Air mixture gas. The results were also compared with SF₆ in the same conditions. The insulating properties will be used to evaluate the dielectric strength of C₄H₂F₆/CO₂ and C₄H₂F₆/Air gas mixture, providing significant fundamental data for its potential use in the medium voltage gas insulated switchgear cabinet.