Comparative Analysis of Topologies to Integrate Photovoltaic Sources in the Feeder Stations of AC Railways

The increasing diffusion of renewable energy sources in the power systems is likely to extend in the near future to the power supply of railways. This paper compares the technical and economic benefits of several configurations with power electronics converters for the integration of photovoltaic (PV) sources into the railway power supply systems. For each of these configurations, a design methodology is proposed for selecting the ratings of the railway power supply components. The requirements for the phase imbalance on the feeding transmission line are assumed in accordance with current regulatory standards and, wherever necessary, phase balancers are added. The design methodology is applied to the power supply of a high-speed railway and the configurations under study are numerically compared based on their technical feasibility and economic cost, using the generation capacity of the PV source as an independent variable. The analysis demonstrates that with a progressive integration of PV sources into railway systems, the configurations with power converters supplying the overhead lines could become more beneficial than more classical solutions where the overhead line is supplied via a transformer.