Simulation research on DC field over-voltage caused by the open-circuit fault in neutral busbar and metallic return

Based on actual parameters of main equipment in Xiangjiaba - Shanghai UHV DC transmission demonstration project, the system simulation model is established. The generating mechanism and distribution law of switching over-voltage caused by open-circuit faults in neutral busbar and metal return is studied. Meanwhile, aiming at the switching time delay of fast earthing switch, the measures to control the over-voltage is presented. The research has certain guidance to the optimization of arrester in the following UHV DC project.