Power Flow Simulation of Flywheel Energy Storage Systems for Tramways

Abstract

Energy storage devices, such as flywheel storages, can be used in railway systems, especially tramways, to save energy from being turned into heat in the braking resistor. This paper provides a quantitative analysis for the possible energy savings by using a flywheel energy storage system in a tramway. For this purpose a flywheel is modeled considering various internal losses. Based on the defined operating strategy, the power flow of the traction system is analyzed for a given driving cycle. The energy consumption of a tram with a flywheel system is compared to the consumption of a conventional tram without an energy storage device and a tram with a storage device based on supercaps. Finally, the influence of the grid feed in power limit on the energy savings is analyzed.