Investigation on dielectric properties of chlorodifluoromethane and mixture with other N2/CO2/air as a promising substitute to SF6 in high voltage application

Sulphur hexafluoride (SF6) has been the most commonly used gas in the electrical industry since 1960s. Due to the high environmental hazards reported by using SF6, the research on to investigate alternative gaseous insulation has become demanding research in high voltage engineering. The refrigerant gas chlorodifluoromethane (CHClF2) with low global warming potential and stable chemical properties possess high dielectric strength due to the presence of fluorine atoms. In this paper, the dielectric strength of CHClF2 and its mixtures with CO2, N2, and Air in the uniform field are investigated under AC, DC and impulse voltage. Buffer gases (CO2, N2, and Air) are added to improve the boiling point of base gas (CHClF2). The dielectric strength increase has also been reported by mixing base gas with N2. Moreover, the synergistic effect, liquefaction temperature, and self-recoverability test were also obtained proving the significance of the research.