No reactors in the switchroom:Active 100 kVA reactive power compensation at the Nacina Ves traction substation

The Nacina Ves container traction substation was built during the electrification of the Bánovce nad Ondavou – Humenné line. It is supplied by a 22 kV cable feeder from the Michalovce electrical station, with a standby feeder from the Humenné electrical station. The long cable feeder supplies capacitive reactive energy into the grid - the billing meters at the station measure it, and ŽSR pays for it. Before the design, we measured the capacitive contribution of the line itself with the MV breakers disconnected.

We deployed two NEXICONTROL 400 050 COMP active compensators in STATCOM mode, 100 kVA in total. They operate in parallel on the LV side of the auxiliary-supply transformers and control continuously within ±50 kVAr per unit - both capacitive and inductive. The supervisory control system evaluates the required reactive power from measurements on both MV feeders, so the compensation keeps working after a switchover to the standby feeder. The IP55-rated units are installed outdoors and take up no space inside the switchroom.

Beyond the constant capacitive reactive power of the line, the converters also compensate the traction node itself - rectifiers, the overhead contact line and the locomotive load, which varies with traffic. The substation has been in operation since December 2025, with web visualization and remote supervision.