Fundamental research of uniform vacuum arc control by magnetic field and its application to VCB

The vacuum arc behavior and high current interruption ability of electrodes applied in the uniform vacuum arc control method are presented. The axial magnetic field (AMF) distribution of this method is unlike that of the conventional AMF distribution. For extremely high interruption current, the arc of the conventional AMF electrode concentrates, causing local heating of the electrode, but the arc of this method diffuses over the whole contact area thus avoiding local heating. The interruption characteristic is investigated. The relationship between the arc energy and the electrical field after the current zero was estimated. The relation among the electrode structure, the arc behavior and the magnetic field distribution between the electrodes is investigated. The vacuum interrupter with this vacuum arc control method is applied for Solid Insulated Switchgear (SIS). These vacuum interrupters are demonstrated to be higher interruption ability than the conventional AMF vacuum interrupter.