Drift characteristics and the multi-field coupling stress mechanism of the pantograph-catenary arc under low air pressure

Abstract

The fault caused by the pantograph-catenary arc is the main factor that threatens the stability of high-speed railway energy transmission. Pantograph-catenary arc vertical drift is more severe than the case under normal pressure, as it is easy to develop the rigid busbar, which may lead to the flashover occurring around the support insulators. A pantograph-catenary arc experiment and diagnosis platform was established, which can simulate low pressure and strong airflow environment, and meanwhile, the variation law of arc drift height with time under different air pressure and airflow velocity is analyzed. Moreover, arc drift characteristics and influencing factors were explored. The physical process of the arc column drifting to the rigid busbar with the jumping mechanism of the arc root on the rigid busbar is summarized. In order to further explore the mechanism of the above physical process, a multi-field stress coupling model was established, as the multi-stress variation law of arc was quantitatively evaluated. The dynamic action mechanism of multi-field stress on arc drifting characteristics was explored, as the physical mechanism of arc drifting under low pressure was theoretically explained. The research results provide theoretical support for arc suppression in high-altitude areas.

Research on driving force and dynamic characteristics of pantograph–catenary arc

“…G i is the coordinate point representing the geometric center of a cylindrical element i, S i is a vector representing the current direction of the element [24]. As shown in figure 2(b), Xu et al [22,23] built an arc chain model, which considers the arc self-magnetic force F mi , thermal buoyancy F ti , wind load F wi , and the air resistance F ai . However, this model ignores the mass of each current element, and the acceleration process is not considered.…”

“…However, this model ignores the mass of each current element, and the acceleration process is not considered. For the convenience of description, the model in this work is called the new model, and the model that ignores the mass and acceleration of current elements is called the old model [22,23]. As shown in figure 2(c), the new model will consider the mass and acceleration of arc.…”

“…Figure 14 compares the arc column stretch length with the magnitude of the wind load, and shows the mechanism of wind load in each process of arc evolution. The magnitude of the wind load is related to the windward area [23]. In the arc initial process, as shown in figure 8, when t = 115 ms, the arc length and windward area are small, so the wind load is also small.…”

“…Figure 15 compares the arc column stretch length with the electromagnetic force, and shows the mechanism of electromagnetic force in each process of arc evolution. The magnitude of the electromagnetic force is related to the degree of arc distortion [23]. During the arc initial process, the arc is stable, and the arc self-magnetic field is almost parallel to the direction of its current, resulting in a small electromagnetic force in this process.…”

“…Cong et al summarized the influence of crosswinds on the secondary arcs [20] and revealed its motion mechanism [21]. Xu et al found that the arc chain model can explain the PC arc behavior from the perspective of driving forces [22], and analyzed the arc development law quantitatively [23].…”