Research status of replacement gases for SF6 in power industry

Abstract

SF6 is widely used in the industrial field due to its stable structure and excellent properties. It is mainly used in electrical insulation equipment. Due to the boiling point of SF6, its use in extremely cold regions has been limited. It is harmful to the health of practitioners due to the toxicity of decomposition products. The gas has limited its wider use because of its strong greenhouse effect. As a result, researchers and electrical equipment manufacturing companies around the world are gradually searching for new environmentally friendly gases and have conducted research and exploration on theory and experiment. In this paper, the current status and existing problems of SF6 are summarized. The research contents and research methods of SF6 alternative gas direction are reviewed from the aspects of insulation performance, interrupter performance, and decomposition performance. The existing research results of the natural gas, SF6 mixed gas, perfluorocarbons, and CnFmX gas are summarized, and the future development trend of alternative gas for SF6 in the electrical industry is proposed.

Stability Valorization of Hydrofluoroolefine HFO-1336mzzE and Its Mixtures under Arc Discharge Conditions

“…Its insulating capacity is 2.5 times higher than air, whereas its arc extinguishing is 100 times higher than the air. 3 However, the Global-warming potential (GWP) of SF 6 is 23,900 CO 2 eq, 4,5 and its extremely stable structure allows it to remain in the atmosphere for 3,200 years without reacting with atmospheric water vapor. 6 Importantly, emissions of fluorinated gases account for 2.1% of total greenhouse gas emissions.…”

Dielectric Withstand of a Mixture of Fluoroketone C5F10O and Air When Cooling Below its Dew Point

“…In the last decades, a few gases have been proposed for use in switchgears as alternatives to SF6 [5,6]. One approach used in the electrotechnical industry is to replace SF6 by known, naturally occurring gases like air or mixtures of CO2, N2 and O2, and increase the gas pressure to compensate their lower intrinsic dielectric and interruption performance.…”

“…The two fluorinated additives that are being presently used in recently launched gas insulated switchgear products are the 1,1,1,3,4,4,4-heptafluoro-3-(trifluoromethyl)-2-butanone, C5fluoroketone (C5-FK) and 2,3,3,3-tetrafluoro-2-(trifluoromethyl)-propanenitrile, C4-fluoronitrile (C4-FN) [6]. These fluids have a very high dielectric performance but a high boiling point that is above the typical minimum operating temperature of the switchgears, so they are used in a gas mixture with a background gas that is usually synthetic air.…”

Breakdown at Multiple Protrusions in SF6 and CO2

“…Therefore, the search for alternative insulation gases has significantly increased during the last years. The most promising gas in HV switchgear applications for replacing SF 6 is CO 2 , which is used in mixtures with low-additive concentrations of, e.g., O 2 , Perfluoroketones (PFK) or Perfluoronitriles (PFN) [8][9][10][11][12]. The additive concentrations are typically in the range of a few percent due to boiling point requirements.…”

“…The effect of surface roughness and protrusions in pure CO 2 was investigated by [29][30][31][32][33]36,37], respectively. Breakdown at surfaces in CO 2 -PFK and CO 2 -PFN mixtures is reviewed in [8][9][10]. The effect of surface roughness at pressures above 1 MPa was investigated, e.g., by [27,36].…”