Power Quality Improvement by using Dynamic Voltage Restorer

The integration of renewable energy sources, smart grid systems and extensive usage of power electronic devices, micro-controlled based device, variable speed drives etc. causes a number of power quality issues including electrical harmonics, voltage sag, voltage swell and imbalance creates an impact on the efficiency of electrical equipment. the energy maintaining poor power quality will affect consumers and their utility equipment's. Power quality means quality of the normal voltage supplied to your facility. Voltage provided should be as close as possible to nominal voltage. The waveform must be pure sine wave free from any harmonics and other disturbances. The growing use of microprocessors and electronic equipment has made us to focus on power quality. Equipment and machinery can be damaged or even fail when subjected to power anomalies. Some of the power quality issues are voltage sag, swell, harmonics, flicker, interruption etc. Among these issues voltage sag is an important issue. This paper investigates about the causes of voltage sag, consequences and its mitigation. Many mitigation devices are available and the most economic effective solution is Dynamic Voltage Restorer (DVR). Simulation has been carried out to evaluate performance. A DVR is simulated in MATLAB/SIMULINK using synchronous reference frame theory.