Voltage Mitigation Technique for ZSI Based Interline Dynamic Voltage Restorer

The Dynamic Voltage Restorer (DVR) provides an advanced and economical solution for both voltage sag and swell problems. The voltage-restoration process involves real-power injection into the distribution system. The Interline DVR (IDVR) proposed in this paper provides a way to compensate the voltage deviation caused in a feeder. The IDVR consists of several DVRs connected to different distribution feeders in the power system sharing common energy storage. Here, one DVR in the IDVR system works in voltage-sag/swell compensation mode while the other DVR in the IDVR system operate in power-flow control mode. The single phase model of the IDVR system is illustrated which is operated by Multiple Pulse Width Modulation (PWM). A new topology based on Z-source inverter is presented in order to enhance the voltage restoration property of dynamic voltage restorer. Z-source inverter would ensure a constant DC voltage across the DC-link during the process of voltage compensation. The modeling of Z-source based dynamic voltage restorer is carried out component wise and their performances are analyzed using MATLAB software. The simulation results shows that the control technique is very effective and yields excellent compensation for voltage sag/swell mitigation.