Abstract: Due to the influence of the current distribution of moving load and the contact conduction force of the arch network, the key components of the catenary structure will generate discharge between the carabiner structure, which will cause the burning of the connection point and affect the operation safety of the system. In order to solve this problem, a research is conducted and an arc transient model of the hinge structure of the hook-and-loop structure locator is established. The influence of branch current on discharge overheating is revealed, and the influence characteristics of arc current, air flow velocity and hook-and-loop separation gap on arc temperature are obtained. Research show that when there is a branch current between the carabiner structures, the arc can be generated and maintained when the carabiner structure is separated. With the increase of the current, the arc temperature increases. With the increase of ambient air velocity, the arc temperature decreases, and with the increase of the gap of the carabiner structure, the arc temperature rises. When the arc current exceeds 200 A, the arc temperature increases sharply and will exceed the melting point of the steel material, resulting in the surface ablation of the carabiner structure. The research provides theoretical basis and data support for the design of carabiner structure of DC traction electric system.