The lightning resistance level of DC grounding pole line is low. It is easy to build arc on insulator string when it is struck by lightning and operated overvoltage. Generally

arc angle is installed at both ends of insulator to prevent DC arc from ablating insulator. At present

there is a lack of research on arc extinguishing mechanism and arc motion process of arc initiation angle. Installation of arc initiation angle is based on operation experience and lack of theoretical basis. In this paper

a chain arc model is adopted

considering the effect of current element viscous force

and a DC arc motion model between arc-initiating angles is established. An algorithm based on a large matrix to store the position coordinates of current element is proposed. A program is programmed in MATLAB to simulate and analyze the arc motion process and arc force. It is concluded that the magnetic field force and thermal buoyancy force are arc extinguishing. The conclusion of the main power supply a theoretical basis for the installation of arc angle. Finally

arc extinguishing experiments are carried out on a small-scale DC arc experimental platform to verify the validity of the proposed model.