Contribution of External Magnetic Field for Increasing Arc Voltage in Magnetic Driven Arc

The arc current reduces to zero when the arc voltage increases and equals to the source voltage during the interruption process of DCCB. Generally, an external magnetic field is applied to the arc for achieving better performance, because the electromagnetic force derived from it can increase the arc voltage increment. However, there are few reports about the physical properties change of arc plasma during its elongation with considering the application of external magnetic field. In this research, physical properties and movement of magnetic driven arc in a parallel electrode with different inter-electrode distance were analyzed. It found out that the anode spot was shifted from the edge to the electrode side by the strong cathode jet, which becomes stronger in a shorter inter-electrode distance. As a result, the arc voltage increased rapidly with applying external magnetic field in shorter inter-electrode distance and the interruption time decreased.