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 this paper, the arc transient model of the hinge structure of the carabiners is established, the effect of the branch current on the overheat is revealed, and the influence characteristics of arc current, air velocity and carabiners separation gap on the arc temperature are obtained. Research shows. When there is a branch current between the carabiner structures, the arc can be generated and maintained when the carabiner structure is separated. As the current increases, the arc temperature rises. With the increase in ambient air flow velocity, the arc temperature decreases, whereas with the enlargement of the gap in the clamping ring structure, the arc temperature increases. With an arc current exceeding 200 A, the arc temperature increases sharply and will exceed the melting point of steel, resulting in surface ablation of the carabiner structure. The study offers a theoretical framework and empirical data to inform the design of carabiner structures within DC traction electrical systems.