Application of battery auxiliary substations in 3kV railway systems

In the paper is presented an auxiliary substation equipped with battery based energy storage system (Auxiliary Battery Substation - ABS) and the benefits for railway applications are shown. The proposed solution is able to reduce the effect of the peak current and voltage drops on weak traditional 3 kV feeding line during high performance trains traction. The ABS also increase the system efficiency by recovering energy during train braking phase and making it available again at the next starting time, minimizing the energy required to the main substation. An extensive simulation framework is performed on a real Italian 3 kV DC railway system feeding a new generation high speed train where the ABS supports conventional supply system. The simulation results confirm the effectiveness of the ABS in terms of peak current reduction and voltage drops compensation. Finally, The ABS allows reducing losses and increasing the energy saving in the railway feeding line.