Distribution system needs to be protected against voltage sags, swells that adversely affect the reliability & quality of power supply at the utility end. These problems can be mitigated with voltage injection method using custom power device, Dynamic Voltage Restorer (DVR). In this paper we design a Dynamic Voltage Restorer (DVR) which is utilized for power quality improvement. The main power quality problems like voltage sag and swell are studied in this paper. The device used to phase out voltage sags and a swell in the distribution lines is the Dynamic Voltage Restorer (DVR). The DVR can restore the load voltage within few milliseconds by injecting series voltage which is actually missing voltage in to system through series connected booster transformer, when it is subjected to voltage sags. 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. This study present compensation of sags and swells voltage during single line to ground, double line to ground and three phase line to ground faults. By using DVR technology, power quality enhances, which is shown in simulation waveform.

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Dynamic Voltage Restorer Voltage Sags Voltage Swells Power Quality