Smart Electrical Infrastructure for AC-Fed Railways With Neutral Zones

This paper presents a proposal to modify power supply systems currently used in ac-fed railways with neutral zones (NZs), in order to allow power-flow routing. The proposed system complements the existing infrastructure with additional power-electronic devices connected in parallel to both sides of the NZs, allowing control of power flow through adjacent electrical sections. The description and control of such a modified railway system is outlined in this paper. In addition, a mixed-integer programming optimization problem is formulated, which minimizes the investment and the operation costs, while ensuring the power supply to the train traffic. This optimization model is used to allow a systematic evaluation of the benefits of implementing such a railway smart grid system. Finally, a section of the high-speed line between Madrid and Barcelona is used as a case study, and the advantages of the proposed system are quantified in two different scenarios.