Technological progress of axial magnetic field vacuum interrupters

New methods have been developed for investigating vacuum arcs and applied to the improvements of vacuum interrupter electrodes. Electrode surface temperature measurements reveal the anode surface melting condition at current interruption and its influence on interruption capability, and digital image processing technology gives a clear understanding of arcing phenomena. Measurements and test results have shown the advantages of axial magnetic field electrodes in increasing the interruption capability of vacuum interrupters. It is confirmed that axial magnetic field electrodes are superior to other types of electrodes, and the authors believe these new investigation methods promote the optimization of the electrode structure and the realization of higher voltage and current rating vacuum interrupters