Dielectric properties of tetrafluoroethane (R134) gas and its mixtures with N2 and air as a sustainable alternative to SF6 in high voltage applications

A gas insulation medium SF6 has been widely employed in Gas Insulated Switchgear (GIS) since the 1960s. However, the high Global Warming Potential (GWP) limits the employment of SF6 gas as insulation medium in power system equipment. Therefore, to reduce environmental hazards, an alternative to SF6 is needed. In this regard, R134 gas seems to be a good replacement for SF6 gas considering the environmental concerns, because GWP of R134 is 94% less and cheap insulation medium, compared to SF6. Considering the aforementioned features of R134 gas, our paper presents an experimental and analytical study of R134 gas and its mixtures with N2 and air. The R134 gas emerged as a strong alternative to SF6 gas and possesses 0.85 times dielectric strength, compared to SF6 gas. We include a comparative study of SF6, R134, and their mixture by evaluating the following aspects: (a) environmental effects and (b) liquification condition. Further, the experimental arrangement, procedures, and testing methodologies are elaborated in this paper. Our work also performs the power frequency breakdown voltage testing of R134 and its mixtures. Furthermore, the Synergistic effect, Self-recoverability, and Liquification are investigated in this paper. Based on our experiments, the final results reveal that R134 is a better insulation medium than SF6.