Improving power quality using energy storage: case railway transformers

Fluctuations in power consumption on the large Danish (132/150 kV) electrical grid is a problem that increases in severity the shorter the timescale of the fluctuations. An area where very large but brief power consumption is seen is in the electrified part of the Danish railway system, where starting trains draw a very large but brief power. In this project, we will install an energy storage device at an electrical railway transformer station, to reduce the peak load on the overlaying electrical grid. The energy storage device will instead continuously draw power from the 132 kV grid and quickly be able to supply this power to the electrical train system when needed. The energy storage device will be a 3.3 MW magnetic flywheel, designed and produced by the Danish company WattsUp Power. The overall aim of the project is to adapt the flywheel for use at a transformer station through design of optimized power electronics and vibration-resistant magnetic bearings for railway application. Once the optimized flywheel has been designed, it will be constructed and subsequently tested, first at a small scale test setup at DTU Elektro, and then at an electrical railway transformer station in northern Zealand.