Investigation of Synthesis and Dielectric Properties of c-C₄F₈O With Its CO₂/N₂ Mixtures as SF₆ Alternatives in Gas-Insulated Applications

Abstract

The usage and emission of SF6 has been regulated because of high Global Warming Potential (GWP) and long atmospheric lifetime as an insulator in high voltage power transmission equipment. This paper proposes c-C4F8O and its mixtures as a substitute for SF6 with low GWP and superior insulation performance. c-C4F8O is synthesized by 1,4-diiodoperfluorobutane and fuming sulfuric acid with the yield of 55.7% under optimal conditions. The GWP of c-C4F8O is about one-third that of SF6 and its dielectric strength is about 1.2–1.4 times that of SF6. CO2 and N2 are mixed with c-C4F8O to lower liquefaction temperature and GWP. The investigation of breakdown voltage and self-recoverability of gas mixtures has shown that the insulation performance and stability of c-C4F8O-N2 is better than c-C4F8O-CO2 mixtures. The decomposition process of c-C4F8O might produce some nonflammable or inexplosive by-products, such as C2F4, c-C2F4O, c-C3F6and CF2O simulated by Gaussian 09. The results indicate that c-C4F8O and N2 mixtures have potential to replace SF6 in electrical equipment.

Keywords

• Synthesis
• perfluorotetrahydrofuran
• insulation performance
• sulfur hexafluoride substitutes