Analysis of Various Topologies for Voltage Sag Compensation of Dynamic Voltage Restorer

During the voltage sag a power electronic device DVR (Dynamic voltage restorer) is considered to be the most efficient solution in electrical power distribution system. In order to mitigate the voltage sag and to restore load voltage to its rated value it is used to inject the three phase voltage in series and synchronism with the feeder at distribution side. A DVR comprises of series transformer, filter circuit, PWM inverter, controller system and a energy storage unit. This paper provides detailed study of the principle of operation, compensation strategies, control methods and the challenges faced by the DVR.