3-D Numerical analysis of diffuse vacuum arcs with an axial magnetic field

The capabilities and advantages of vacuum interrupters (VIs) have been widely recognized on switching and controlling the fault currents in medium voltage level, and there have been doing various research and developments for using VIs in transmission and distribution lines due to its environmental friendliness nowadays. An axial magnetic field (AMF) electrode has more advantages of the switching capability than other contact designs such as reducing the arc voltage, securing higher current value for transferring from the constriction arc to the diffuse arc and regulating the arc current distribution. The arc constriction could increase the heat flux and the local temperature on the electrodes and result in the surface melting, which have undesirable influences on the characteristics of vacuum arc and surroundings. In the present study, we calculated 3-D diffuse vacuum arcs with an axial magnetic field using a commercial FEM package, ANSYS. The vacuum arc has been modeled with the sequential coupling method of two different fields, which are on the electromagnetic and thermal-flow. Arc constriction with applied currents could be predicted with the results of temperature distribution, and further modeling procedure will be followed for the detailed constriction phenomena of vacuum arcs with an axial magnetic field.