Abstract: Voltage sag and voltage swell are two of the most important power-quality problems that encompass almost 85% of the distribution system power quality problems. The dynamic voltage restorer (DVR) is one of the modern devices used in distribution systems to protect consumers against sudden changes in voltage amplitude. In this paper, a multifunctional DVR control strategy is proposed along with Posicast and P+Resonant controllers. With the help of these controllers the transient response of DVR can be improved and also in DVR response, the steady state error can be eliminated.

Keywords: Dynamic voltage restorers (DVR), power quality, voltage sag, voltage swell.