Mitigation of Transformer Saturation in DVR based on Flux Linkage Feedback Control

Abstract

Dynamic voltage restorer (DVR) is a device connected in series between power grid and sensitive load to protect the latter from voltage quality problems of the former. Saturation and inrush current are the important issues of DVR with series transformer, which may seriously affects the normal operation of the transformer and cause damage to the equipment or trigger over-current protection. To prevent transformer saturation and inrush current, a mitigation strategy of transformer saturation in DVR based on flux linkage feedback control is proposed in this paper. This method takes the flux linkage as a system state variable, and includes flux linkage loop in the control system to limit the DC flux linkage without affecting the steady-state compensation performance of DVR. The flux feedback control method is verified by simulation, and then a 0.5 kVA single-phase DVR prototype is built to validate the proposed strategy.