Study on the Insulation Properties of Trans-HFO-1336mzz Mixtures

Trans-HFO-1336mzz has triggered much attention from experts and scholars in the electric power industry due to its excellent insulation performance, environmental effect, and biological safety. In this work, the dielectric breakdown experiment of three mixed gases, trans-HFO-1336mzz/Air mixture, trans-HFO-1336mzz/CO2 (carbon dioxide) mixture, and trans-HFO-1336mzz/N2 (nitrogen) mixture was carried out under the plate-plate electrode. By linearly fitting the curves between breakdown voltage and p•d, the critical breakdown electric field intensity (Ecr) of three kinds of mixed gases was obtained. Related results indicated that the order of the Ecr is trans-HFO-1336mzz/Air mixture > trans-HFO-1336mzz/CO2 mixture > trans-HFO-1336mzz/N2 mixture. In particular, the Ecr of 20% trans-HFO-1336mzz/80% Air mixture and 20% trans-HFO-1336mzz/80% CO2 mixture can reach 0.69 and 0.67 times that of pure SF6, respectively. Their insulation strength is close to that of 20% SF6/80% N2 mixture, which has been adopted in GIL as a substitute gas for SF6. This work showed that Air and CO2 are more suitable to be added to trans-HFO-1336mzz than N2.