Analysis of Arc Dynamic Characteristics in DC Disconnecting Switch

As a control and protection device of photovoltaic power generation system, the DC disconnecting switches are used extensively. The interruption capacity is an important index of DC disconnecting switch. The interruption capacity is effected by dynamic characteristics of arc. Therefore, the dynamic characteristics of arc is analyzed by MHD simulation. The 2-D MHD model of disconnecting switch is built and the motion process of moving contact is considered. The temperature, pressure distribution, arc voltage and arc current curves are obtained by simulation. The results show that the velocity of arc motion is slowly and the utilization rate of the splitter plate is lower. It leads to the arcing time is longer. Therefore, the permanent magnet and gassing material can be added to improve the arc extinguishing ability.