Energy Storage Systems in DC Railways for Improving Operating Conditions of AC Power Grids

Energy storage systems (ESSs) are extensively investigated solutions for voltage regulation and energy saving in traction railway system. Furthermore, ESSs can have a considerably impact on the AC grid also by mitigating voltage drops and peak currents. In this paper, the impact of on-board ESSs and those installed along the track in support of the DC feeder system is investigated focusing on the voltages and currents of the AC grid. The AC/DC power flow is solved by implementing an iterative algorithm. A simulation framework based on a real Italian DC railway system show the effectiveness of the proposed methodology, and the obtained results are commented and discussed.