Aziz Tashackori - Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
Seyed Hossein Hosseini
Mehran Sabahi
Tohid Nouri

In this paper a three-phase four-wire Dynamic Voltage Restorer (DVR) is proposed to inject required compensating series voltage to the electric power system insuch a way that continuous sinusoidal voltage is seen at load side ever at heavy fault occurrences at utility side. The proposed DVR is composed of a three-phase four-leg inverterand a three-phase high frequency harmonic filter that are connected to the utility by three single-phase powertransformers. Three dimensional space vector modulation (3DSVM) is applied to the proposed DVR to generate switchingpulses for power switches. Fourth added wire enables the DVRto compensate unbalance voltage sag and swell that are custom power quality problems in electrical utility. The performance ofthe structure and applied switching scheme under both balanced and unbalanced sag and swell are validated by simulations in PSCAD-EMTDC software

DVR, 3DSVM, Balanced and Unbalanced Disturbance, Power Quality