Train Diagram for Optimal Evacuation With Self-Adaptive Voltage Loss and Multi-Train Organization Constraints in Autotransformer Supply Systems

Power systems in remote areas are highly vulnerable, often leading to outages that disrupt traction power supply systems (TPSSs). This paper proposes a scheme to optimize the evacuation of electric locomotives within supply sections fed by an interconnected microgrid following the disconnection of the external power supply system (EPSS). Specifically, this paper begins by presenting a multi-train operational organization (MTOO) constraint, based on a velocity-time mesh, to create a train evacuation diagram that leverages a moving block system to prevent collisions. Next, it formulates self-adaptive voltage loss constraints tailored for high-capacity routes to maintain safe voltage levels. Finally, the paper brings forward device models, including Vv transformers, diesel generators, and energy storage systems considering negative sequence current (NSC) endurance, and establishes three-phase power flow constraints to ensure coordinated and optimal evacuation. The entire model is linearized into a mixed-integer linear programming (MILP) framework, and numerical results from two arms of a traction substation (TS) in a single-track autotransformer (AT) TPSS demonstrate the effectiveness of the well-crafted scheme.