Pulsed breakdown voltage characteristics of pressurized carbon dioxide up to supercritical conditions

Statistical characteristics of pulsed breakdown voltage of pressurized carbon dioxide up to supercritical condition were investigated experimentally. The tested gap is a sphere-to-sphere and the gap length and sphere diameter are around 140 ¿m and 20 mm, respectively. The experimental results show the followings: 1) in the supercritical phase, the scattering in measured breakdown voltage increases with increasing the medium density, 2) the shape parameters in Weibull distribution of breakdown voltage at gas, liquid and supercritical phase are the range of 4 ~ 25, 5.5 ~ 9 and 4 ~ 29, respectively, 3) the maximum shape parameter appears in the density range of 200 to 300 kg m^-3 in supercritical phase, and 4) two values of shape parameter were observed at the measurement conditions of 580 kg m^-3 and 787 kg m^-3 in supercritical phase.