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

Zhanyang Gao,Yi Wang,Wenjun Zhou,Ruichao Peng,Ping Yu,Shiyao Wang,Yunbai Luo

doi:10.1109/access.2019.2961694

Zhanyang Gao, Yi Wang + Show 5 more

Open Access

https://doi.org/10.1109/access.2019.2961694

Copy DOI

Abstract

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 SF6 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.

Highlights

SF6 has been widely used in the gas insulated switchgear (GIS) and gas insulated lines (GIL) due to its superior features, such as outstanding dielectric strength, low liquefaction temperature, excellent chemical stability and selfrecoverability
Many alternative gases and gas mixtures with low Global Warming Potential (GWP) have been researched, such as N2, CO2, CF3I and C4F7N et al The dielectric strength of air, N2 and CO2 is about onethird that of SF6 and can only be used in low voltage electrical equipment [7], [8]
In summary, c-C4F8O was successfully synthesized with the yield of 55.7% when the molar ratio of 1,4-diiodoperfluorobutane and fuming sulfuric acid of containing 50% SO3 was 11:1 under 80 ◦C; the breakdown voltage of c-C4F8O and its mixtures were tested with properties in environmental and physical aspects analyzed

Summary

INTRODUCTION

SF6 has been widely used in the gas insulated switchgear (GIS) and gas insulated lines (GIL) due to its superior features, such as outstanding dielectric strength, low liquefaction temperature, excellent chemical stability and selfrecoverability. Some power companies employed mixture of SF6 and N2 as insulation gas to alleviate the greenhouse effect without impacting. Many alternative gases and gas mixtures with low GWP have been researched, such as N2, CO2, CF3I and C4F7N (heptafluoroisobutyronitrile) et al The dielectric strength of air, N2 and CO2 is about onethird that of SF6 and can only be used in low voltage electrical equipment [7], [8]. Minnesota Mining and Manufacturing and General Electric Company put forward a g3 gas, mixture of C4F7N with CO2 [1], [13], a new eco-friendly candidate in terms of remarkable insulation performance and low greenhouse effect but decomposition products are toxic [14], [15], which limited its application to some extent. The electrodes were polished by abrasive paper in 5000 mesh and cleaned by anhydrous alcohol before the test

CALCUATION METHOD

BREAKDOWN VOLTAGE OF c-C4F8O AND ITS MIXTURES

RESULTS AND DISCUSSION

CONCLUSION