Technical and performance aspects of a dynamic voltage restorer

One of the major issues in improving power quality in distribution networks is the mitigation of voltage sags. Voltage sags in distribution networks caused by system faults can adversely affect sensitive electrical equipment in industrial production processes, such as in semiconductor fabrication, resulting in substantial financial losses. A safe, reliable and clean power supply to these industries is therefore a prerequisite to their profitable operation. A dynamic voltage restorer (DVR), with its excellent dynamic capabilities, when installed between the supply and a critical load feeder, can compensate for voltage sags, restoring line voltage to its nominal value within a few milliseconds and hence avoiding any power disruption to that load. This paper presents the technical aspects of designing an integrated gate commutated thyristor (IGCT) based DVR shown, a new device capable of meeting the stringent requirements of voltage sags mitigation. Furthermore, performance assessments of the DVR using a real-time hardware simulator model and computer simulations are discussed.