Dynamic Control Strategy in Medium Voltage DVR for Mitigating Voltage Sags/Swells

This paper presents control algorithm for dynamic voltage restorer (DVR) to improve voltage quality problems such as voltage sags/swells in distribution systems. When voltage sags/swells occur, possibly, due to faults and some load switching, DVR has to detect the problem and inject appropriate voltage component as soon as possible. The paper proposes a dynamic control based on feedforward and feedback control. The proposed control enhances the performance of DVR. In the proposed control, voltage and current closed-loop controllers are considered. A simple distribution system with sensitive load and DVR at 22 kV is used to test the proposed control algorithm. The simulation results show that the proposed control given a better voltage quality and enhances the performance of DVR.