SF₆ガス不平等電界中における絶縁破壊機構の実験的考察

抄録

Experimental investigations of the breakdown mechanism in SF₆ gas by model electrode configurations are performed for DC and lightning impulse voltages. Electrodes are composed of a rod to a disk. The gap distance is adjusted by changing the radius of the rod electrode. The amount of gap distance and rod radius is kept constant(15mm). Some peculiar phenomena of breakdown characteristics on the gas pressure and the gap distance were observed. The maximum DC breakdown voltage as a function of gas pressure are given at 0.3MPa for both positive and negative polarities except the gap distance of 7.5mm. At the condition of gap distance of 7.5mm, the breakdown voltages monotonously increase without the crest value as increase of the gas pressure for both polarities. The DC breakdown voltage in the gas pressure of 0.3MPa is higher than that at lightning impulse voltage at some conditions of the electrode configuration. The lightning impulse breakdown voltages have same values for both polarities and also they are same as that of DC voltage in gas pressures of 0.2, 0.3 and 0.4MPa under some conditions of the electrode configuration.
These results are well analyzed by taking account of (a) an electric field distribution without space charge and (b) a schematic distribution of negative and positive space charges.