How Electrical Arcing Governs Wear and Performance in Current-Carrying Pantograph Contacts

The pantograph–catenary system serves as the core power supply device, ensuring stable operation of high-speed trains, and its contact interface represents a typical current-carrying friction system, where the introduction of electric current significantly complicates the wear mechanisms. The coupling effect of mechanical wear and electrical wear exacerbates damage to and degradation of carbon strip materials, while electric arcs induced by unstable contact states directly regulate the tribological characteristics and electrical conductivity of the friction pair. To investigate the current-carrying friction and wear behavior of carbon strips under the dominant effect of electric arcs, this study simulated the irregularity conditions of contact wires, observed the evolution characteristics of electric arcs, and systematically analyzed the effects of test current and contact load on the damage characteristics and current-carrying performance of the contact pair. The results indicate that arc morphology exhibits differentiated characteristics across friction cycles, with significant fluctuations in arc intensity. Regarding the friction coefficient, under a contact load of 25 N, the friction coefficients corresponding to currents of 0 A, 40 A, and 80 A are 0.378, 0.242, and 0.335, respectively; under a contact load of 50 N, the corresponding values are 0.432, 0.180, and 0.209, respectively. The friction coefficients under current-free conditions are consistently higher than those under current-carrying conditions. In terms of wear rate, under a contact load of 25 N, the wear rates at 0 A, 40 A, and 80 A are 0.0069, 0.299, and 2.70 mm3/(N·m), respectively; under a contact load of 50 N, they are 0.010, 0.133, and 1.133 mm3/(N·m), respectively. No positive correlation is observed between contact load and the wear rate of the carbon-based friction pair, whereas increasing test current significantly exacerbates material damage. Regarding contact resistance, under a contact load of 25 N, the contact resistances at 40 A and 80 A are 34.7 Ω and 46.6 Ω, respectively; under a contact load of 50 N, they are 27.7 Ω and 37.9 Ω, respectively, indicating that lower contact loads correspond to higher contact resistances, and higher test currents also result in higher contact resistances. In summary, both increasing current and decreasing contact load aggravate the electrical damage to the contact pair materials, while increasing contact load exerts a significant inhibitory effect on electrical damage. This study provides theoretical insights into the damage mechanism and arc morphology evolution laws induced by electric arcs under contact wire irregularity conditions.