Phase advance compensation of voltage sags using full bridge inverter based DVR

Voltage sag is considered as the most expensive power quality problem. With the advent of power electronics, custom power devices are introduced to mitigate the sag issues. Among the custom power devices, Dynamic Voltage Restorer (DVR) is the most cost-effective one. The voltage injected in series by the DVR compensates the load profile during sag events. The compensation techniques such as in-phase, energy minimized and phase advance methods determine the way in which the DVR voltage is injected into the grid. By providing a phase advance to the DVR voltage with respect to the supply voltage gives the merit of reduced active power injection and thereby reduces the rating of energy storage. The disadvantages such as increased DVR voltage magnitude, phase shift, load swings and discontinuity of wave shape are associated with this compensation technique. This method is suitable for magnitude sensitive loads. This paper presents simulation results showing the compensation of both sag and swell using phase advance compensation.