A NOVEL METHOD FOR GLOBAL VOLTAGE SAG COMPENSATION IN IEEE 69 BUS DISTRIBUTION SYSTEM BY DYNAMIC VOLTAGE RESTORERS

In the paper, a new model for optimizing the placement of Dynamic Voltage Restorers (DVR) for global voltage sag mitigation in a distribution system is introduced. The placement of one or a number of DVRs is optimally selected on the basic of minimizing the system average RMS variation frequency index SARFIX of the system of interest. For calculating SARFIX of the system of interest with the presence of a number of DVRs, a new method for modelling different cases of DVR placement for mitigating globally voltage sag due to short-circuits in a distribution system using the Thevenin's superposition principle is proposed. The DVR's performance of global voltage sag mitigation is considered for a given maximum current generated by the DVR. The paper uses the IEEE 69-buses distribution system as the test system for voltage sag simulation and discussion on cases of study for optimal placement of DVRs.