Investigation on insulation properties of HFO‐1336mzz(E) and N ₂ /CO ₂ mixtures as SF ₆ substitutes in gas‐insulated electrical applications

Abstract

Abstract The emissions of SF 6 have been restricted owing to 3400 years of atmospheric lifetime and high global warming potential (GWP) as an insulating gas in gas‐insulated electrical equipment. In this study, HFO‐1336mzz(E) and N 2 /CO 2 mixtures are proposed as SF 6 substitutes for their short atmospheric lifetime, low GWP and superior insulation performance. The GWP of HFO‐1336mzz(E) is only 18 and its atmospheric lifetime is days to weeks. The breakdown voltage of 25% HFO‐1336mzz(E) and N 2 /CO 2 mixtures is about 85% that of pure SF 6 under alternating current. The self‐recovery ability of HFO‐1336mzz(E) and CO 2 mixtures is superior to that of HFO‐1336mzz(E) and N 2 mixtures. The decomposition characteristic of HFO‐1336mzz(E) shows that a tiny amount of its gas might initiate a carbonisation reaction to form carbon after multiple breakdown tests, which is verified by observations using energy dispersive X‐rays spectroscopy and scanning electron microscope. The acute toxicity test of HFO‐1336mzz(E) indicates that the gas is non‐toxic. The results show that HFO‐1336mzz(E) and N 2 /CO 2 mixtures are potential substitutes for SF 6 in electrical applications.