Influence and mechanism of pressure on SF6 decomposition components of gas-insulated switchgear under positive DC partial discharge

To clarify the influence of pressure on SF6 decomposition under positive DC partial discharge (PD), SF6-positive DC partial discharge decomposition experiments at different pressures were carried out. We found that the contents of SF6 primary decomposition products are proportional to openBdP/E. Keeping the chamber volume and external temperature constant, the difference of air chamber pressure means that the electronic mean free path is different. So, different pressures make a difference in the energy of free electrons obtained in a single flight, which results in the difference in the reaction rates of SF6 primary decomposition and further influences the formation of SF6 PD characteristic decomposition components. (c) 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.