Analysis of Last Development Results for High Voltage Circuit-breakers Using New G3 Gas

Abstract

Among many alternative gases proposed to replace SF6 as insulating gas, g<sup>3</sup> (green gas for grid), fluoronitril based component officially introduced at CIGRE 2014, can be now used for insulation projects and new environmental friendly circuit breakers. This gas mixture g<sup>3</sup>, presents a reduction of the global warming potential by 98% compared to SF<sub>6</sub> gas and shows quite good dielectric withstand capability. Many new investigations about thermal and chemical behavior have been done and are precised in this paper. Last switching test campaigns will be presented for 145 kV applications. Simulation tools should be updated to be applicable to these projects. Developments and comparisons with last test results will be analyzed.

Ablation-Dominated Arcs in CO2 Atmosphere - Part I: Temperature Determination near Current Zero

“…However, only a limited selection remains in the actual investigations. Gas mixtures containing fluoro-nitriles (C 4 F 7 N) or fluoro-ketones (C 5 F 10 O) as minority components (<20 %) have been identified as most promising alternatives to SF in high-voltage gas-insulated switchgear applications, because of their low global warming potential together with their dielectric strength values being comparable to SF 6 [5][6][7]. Due to high boiling points (at 1 bar) of the fluoro-ketones (27 • C) and fluoro-nitriles (-4.7 • C), gas mixtures with carbon dioxide CO 2 as buffer gas prevent liquefaction at temperatures below -30 • C. One of the most promising alternatives that has less limitations concerning temperature range and greenhouse effect but reasonable electrical insulation is CO 2 [8][9][10].…”

Ablation-Dominated Arcs in CO2 Atmosphere—Part I: Temperature Determination near Current Zero

“…However, only a limited selection remains in the actual investigations. Gas mixtures containing fluoro-nitriles (C 4 F 7 N) or fluoro-ketones (C 5 F 10 O) as minority components (<20%) have been identified as the most promising alternatives to SF 6 in high-voltage gas-insulated switchgear applications because of their low global warming potential together with their dielectric strength values being comparable to SF 6 [5][6][7]. Due to high boiling points (at 1 bar) of the fluoro-ketones (27 • C) and fluoro-nitriles (−4.7 • C), gas mixtures with carbon dioxide CO 2 as buffer gas prevent liquefaction at temperatures below −30 • C. One of the most promising alternatives that has less limitations concerning temperature range and greenhouse effect but reasonable electrical insulation is CO 2 [8][9][10].…”