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

The usage and emission of SF
₆
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-C
₄
F
₈
O and its mixtures as a substitute for SF
₆
with low GWP and superior insulation performance. c-C
₄
F
₈
O is synthesized by 1,4-diiodoperfluorobutane and fuming sulfuric acid with the yield of 55.7% under optimal conditions. The GWP of c-C
₄
F
₈
O is about one-third that of SF
₆
and its dielectric strength is about 1.2–1.4 times that of SF
₆
. CO
₂
and N
₂
are mixed with c-C
₄
F
₈
O 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-C
₄
F
₈
O-N
₂
is better than c-C
₄
F
₈
O-CO
₂
mixtures. The decomposition process of c-C
₄
F
₈
O might produce some nonflammable or inexplosive by-products, such as C
₂
F
₄
, c-C
₂
F
₄
O, c-C
₃
F
₆
and CF
₂
O simulated by Gaussian 09. The results indicate that c-C
₄
F
₈
O and N
₂
mixtures have potential to replace SF
₆
in electrical equipment.