Study on voltage sags compensation strategy for dynamic voltage restorer

Dynamic voltage restorer can cost-effectively mitigate voltage sags, and its effect is determined by compensation strategy. For different durations and characteristics of voltage sags, a single compensation strategy is difficult to simultaneously consider the compensation quality and duration. Three basic compensation methods and characteristics of voltage sags are analyzed, and then a generalized compensation strategy based on pre-fault and minimum energy compensation is proposed. The strategy can automatically adopt appropriate compensation method according to voltage sag’s duration and characteristics. Thus the compensation quality is ensured and the compensation duration is extended if necessary. The implementation method is then suggested. Simulation results demonstrate the efficacy and operability of the proposed compensation strategy.