Voltage Quality improvement by Dynamic Voltage Restorer Modeling

Voltage magnitude, waveform and frequency are the major factors that dictate the quality of power. The widespread application of non-linear power electronic loads has brought about degradation of power quality. Of all the power quality issues, voltage sags are the major cause of 80% of the problems experienced by sensitive loads. A Dynamic Voltage Restorer is a power quality device capable of protecting such loads against voltage variations. It injects a dynamically controlled voltage in series with the supply voltage through a booster transformer to correct the load voltage . Generally DVR can be connected to grid through inverter topologies such as Voltage Source Inverter (VSI) or Current Source Inverter (CSI).This device can be implemented to protect a group of medium or low voltage consumers. In this paper a model of a DVR for voltage and power injection, by the compensation method and phase advance voltage restoration method has been compared.