Arc Erosion Behaviors of Pantograph of High-Speed Train During Its Rise and Fall Processes

Arc melting pools are generated when the pantograph and catenary (PAC) are offline during the rise and fall of the pantograph. They can lead to the material damage, accelerated wear, increased splashing, and exacerbated PAC fatigue through the thermal cycling, shortening its service life. In this paper, the voltage and current are measured by a high-speed PAC experimental platform when the PAC occur the offline discharge. And the arc erosion images are obtained using a scanning electron microscope. Based on the principle of the magnetohydrodynamics, a simulation model of the PAC arc is established and its correctness is verified by comparing the experimental data. The distribution of the heat flow input density of the arc is obtained by adopting the moving mesh technique and coupling the actual auto-transformer (AT) traction grid circuit. Meanwhile, the melting solidification model and evaporation sublimation model are introduced to study the behavior of the material erosion by the arc when the pantograph rises and lowers. When the PAC offline discharge occurs during the rise of the pantograph, the heat flow density is concentrated and the temperatures of the contact line and pantograph are 3550 K and 4290 K, respectively. The melting pool is of a deep and narrow type. Its depth is 1.71 mm, which is 80% more than that during the fall of the pantograph. While its width decreases by 17.48% compared with that during the fall of the pantograph, which increases the risk of the localized overheating and thermal stresses. As the pantograph falls, the density of the heat flow decreases and the temperature of the contact point is lowered. The melting pool is shallow and wide, making it more susceptible to splashing and accelerating the wear. The increased temperature in the melting pool triggers the Marangoni effect, which leads to the eddy currents. They increase the instability and spattering on the surface of the pantograph, accelerating the material damage. The innovation of this paper lies in the integration of the arc model, erosion model, and AT traction circuits, and the introduction of the Marangoni force, evaporation-sublimation behaviors, and moving mesh technology, to systematically study the PAC erosion behaviors during the rise and fall of the pantograph. Its purpose is to provide theoretical support for the selection of the PAC materials, their structural design, and preventive maintenance.