Multiport converters and ESS on 3 kV DC railway lines: case study for braking energy savings

In regional and local 3 kV DC railway lines, Energy Storage Systems (ESS) along the catenary can manage energy coming from electrical braking; in the actual low-carbon economy scenario, besides environmental considerations, better energy utilization goes to a general rationalization of the existing and future electrical substations. Modular multiport converters based on Power Electronic Transformers (PET) and ESS can be used for this purpose. This work analyzes as case study a regional 3 kV DC line, obtaining by simulations and GPS measurements the train current and the pantograph voltage profile on the catenary. Energy savings are calculated placing ESS and multiport converters inside existing substations.