Rail Voltage Stabilization Systems
Electric trains and trams generally operate at voltages between 600-1500V. These system voltages are derived from the available grid power. Grid power is susceptible to changes and fluctuations based on overall load on the system. As an example if multiple train lines are running and stopping and starting simultaneously, the grid voltage could drop sufficiently to affect the performance of the train or tram. Consequently, energy storage systems (ESS) have been developed to combat this issue. The ESS can then be used in conjunction with the grid power to provide the necessary energy for the train/tram, without negatively affecting the overall grid energy thereby being referred to as ‘voltage stabilization systems’. Generally these systems are utilized in two forms, on-board and wayside. As the names indicate, one system would be outside the train/tram at a fixed location, and the other would be on board the train or tram. These systems utilize regenerative braking technology to store kinetic energy developed when the train/tram brakes for use at a later time when increased demand is required. These ESS are comprised of a bank of ultracapacitor modules that are discharged during acceleration and recharged during braking.