Transient Arcing Characteristics of the Pantograph–Catenary System in Electrical Sectioning Overlaps

Transient arcing often occurs as an electric locomotive traverses an electrical sectioning overlap (ESO), deteriorating current collection stability and reducing the durability of the pantograph–catenary (PC) system. In this study, the formation mechanism and electrical evolution characteristics of transient arcing in the ESO region are investigated through theoretical analysis and numerical simulations. First, based on the dynamic motion of the locomotive passing through the ESO, the transient arcing mechanism of the ESO is clarified, and the plasma characteristics of the arc are described. Then, the electromagnetic, airflow, and thermal field interactions within the PC contact gap during arc ignition are analyzed. A Multiphysics coupled PC arc model is developed, incorporating aerodynamic, electromagnetic, and heat transfer effects. Subsequently, finite element meshing and boundary conditions are applied to simulate the transient evolution of the ESO arc. Finally, the transient arcing characteristics of the ESO are analyzed. The results indicate that the current density is highly concentrated at the initial arcing stage and gradually forms an axially symmetric conductive channel (approximately 107 A/m2), which shifts upward as the contact gap increases. Moreover, due to the geometric discontinuity of the ESO, a strong localized electric field develops near the wire edge, leading to arc root migration and reignition.