Simulation and analysis of voltage sag mitigation using active series voltage injection

The analyses of voltage sag and its mitigation techniques have received a lot of attention in recent years. Through the fictitious three-phase voltages and the voltage conversion, a new method that can be used to instantaneously quantify the magnitude, duration and phase-angle jump of voltage sag is described in this paper. Considering the actual power quality disturbances, a low pass filter is used to obtain the RMS value of the voltage. The deficiencies of the classical RMS computations for classifying voltage sags are overcome with the proposed method. The method is efficient for the evaluation of voltage sags and the injection for correcting voltage sags in real time on series compensation devices. Taking into account the actual disturbances and the injection capability, the control strategy used in series device is given. Finally, simulation results ate presented to demonstrate the validity of the proposed method.