The Discharge Development and Arc Modes in Vacuum at A Long Gap Distance in Vacuum Interrupters

Abstract

The influence of an arc current on the discharge development and thearc modes of a single coil type axial magnetic field (AMF) electrodewere investigated by a high-speed charge couple device (CCD) videocamera in a long gap distance of 40 mm. The distribution of theaxial magnetic field of the single coil type AMF electrode wascomputed. By computational results, the single coil type AMFelectrode could generate higher axial magnetic flux density than theslot type AMF electrode. It was found that the single coil type AMFelectrode could perform better than the slot type AMF electrode withthe same designing parameters. And the development of the arc modesexperienced diffuse mode, constricted but unstable mode, andconstricted and stable mode with the amplitude of the arc currentincreasing. The correlation between the vacuum arc and the noisecomponents of arc voltage was investigated too. The interruptioncapability could be known in a practical commercial vacuuminterrupter by the test results in a demountable vacuum interrupter(DVC) with a electrode diameter of 50 mm and a gap distance of40 mm.The test results could provide reference to design the highvoltage vacuum interrupter adopting the single coil type AMFelectrode.