IMPROVEMENT OF VOLTAGE SAG MITIGATION USING DYNAMIC VOLTAGE RESTORER (DVR)

The modeling and analysis of Dynamic Voltage Restorer (DVR) implementation for improving the voltage sag due to the motor starting and disturbance occurred in the system is discussed in this paper. DVR is installed through a transformer in series connection between the feeder and a sensitive load to compensate the voltage sag. To show the impact of DVR implementation, the dynamic analysis is performed with the following short-circuit scenarios such as single-phase, double-phase-, and three-phase to ground faults. In addition, the voltage sag due to the motor starting is also investigated in this paper. Based on the simulation results show that the voltage sag reach 0.83pu, 0.78pu, and 0.69pu for the single-, double-, three-phase to ground faults implemented respectively. The DVR implementation mitigates the voltage sag with improving the voltage up to 0.99pu, 0.95pu, and 0.91pu for the single-, double-, three-phase to ground faults cases respectively. The DVR implementation also improves the voltage profile during the motor starting of the largest motor load with a capacity of 55 kW up to 0.99pu instead of without the DVR implementation which the voltage sag reach to 0.92pu. The increasing of voltage profile improvement on the system will need more active and reactive powers acquired from the DVR.