Reactive power compensation in railways using active impedance concept

In this paper a new active impedance topology, employing AC-Choppers is proposed for reactive power compensation in 25 KV/50Hz railways. The good behaviour of AC-AC converters in terms of losses respect to other solutions like VSI based STATCOM, make this solution really interesting in high power single phase systems like railway networks. The concept is applied to a substation in the French Railways. A design method is proposed and simulation results confirm the good working of this low cost and low losses solution. Finally, experimental results, achieved on a 1.2MVAR prototype are presented.