The Development of SF6 Green Substitute Gas

Abstract

Due to its high greenhouse effect, the use of SF6 as the main insulating gas is restricted in the electric power field. Along with the aim of environmental protection, the search for new alternative gases with a lower greenhouse effect and higher insulation strength has received a lot of attention. The properties of alternative gases have a vital impact on the performance of medium-voltage power distribution equipment. Firstly, based on the existing liquefaction temperatures of SF6/N2, SF6/CO2, and SF6/CF4, the calculated liquefaction temperatures were expanded to 0.7 MPa. Combining the Antoine vapor-pressure equation and the basic law of vapor–liquid balance, the vapor pressures of SF6/N2, CF3I/N2, c-C4F8/N2, C4-PFN/N2, C4-PFN/CO2, and C5-PFK/CO2 were obtained. Secondly, the critical breakdown field strength was analyzed for C4-PFN/CO2, C5-PFK/CO2, SF6, CF3I/N2, C5-PFK/Air, and c-C4F8/N2. Finally, the GWPs of SF6/N2, C4-PFN/N2, C4-PFN/CO2, C5-PFK/CO2, and C5-PFK/N2 were discussed. The results show that the liquefaction temperature gradually decreases as the pressure rises; SF6/N2 has the highest vapor pressure at −5 °C; the critical breakdown field strengths of several mixtures are higher than that of SF6.

Metal–organic cages for gas adsorption and separation

“…Despite its extremely low concentration in the atmosphere, SF 6 has a 22 800 times greater greenhouse effect compared to carbon dioxide. [42][43][44] As a material suitable for gas adsorption, MOCs have demonstrated their excellence as candidates for encapsulating SF 6 gas. In 2011, Nitschke and co-workers reported a water soluble tetrahedron MOC-10 through coordination-driven self-assembly (Fig.…”

Comparison between the PD Characteristics of g3 and Dry Air for Gas-Insulated Switchgears

“…Kieffel and colleagues [24] investigated the dielectric performance of g 3 compared to SF 6 under lightning impulse, and the result shows that its dielectric performance at 0.67 to 0.82 MPa is equivalent to between 87% and 96% of that of SF 6 at 0.55 MPa. In case of the dry air, which is composed of N 2 and O 2 , Jiang and colleagues [25] concluded that the dielectric strength of dry air is higher than that of N 2 and O 2 at 0.5 MPa. In addition, Li and colleagues [26] studied the impulse insulation characteristics of dry air according to gas pressure, and the results show that a 50% breakdown voltage of dry air is approximately three times lower than that of SF 6 at the same pressure.…”