抄録
Transient axial distributions of post-arc temperature and its electrical resistivity were measured in a flat-type SF6 gas-blast quenching chamber. Iron was intentionally used as an electrode material, since Fe spectral lines at wavelengths of 426 and 443nm have very much higher radiation intensities than lines of S+, F or Cu at temperatures below 5000K. The two-line method using these Fe spectral lines permitted to determine post-arc temperature T up to 100μs after current zero. From the temperature thus obtained, the electrical resistivity pres of post-arc were determined. The results revealed that the pres at the nozzle throat rose drastically with a lapse of time after current zero. Furthermore, the low- pres region diminished from the nozzle throat to the electrodes in arc extinction process. This process of pres was interpreted as the opening process of fictitious contacts made of thermal plasma. The opening velocity of the fictitious contacts was estimated to be more than 100m/s. The behaviours of the fictitious contacts in cases that transient recovery voltage was applied to the electrodes were obtained by solving the energy conservation equation.The results may give one of the essential facts in the arc interruption phenomena.
