Control of a ULTC considering the dispatch schedule of capacitors in a distribution system

This paper proposes a coordinated control method for an under-load tap changer (ULTC) with switching capacitors in distribution systems to reduce the operation numbers of both devices. The proposed method consists of two stages. In the first stage, the dispatch schedule of capacitors is determined using a genetic algorithm with forecasted loads to reduce the power loss and to improve the voltage profile during a day. In the second stage, each capacitor operates according to this dispatch schedule and the ULTC is controlled in real time with the modified reference voltages considering the dispatch schedule of the capacitors. Simulation results show that the proposed method performs better than a conventional control method.