Compensation of voltage sag and harmonics by dynamic voltage restorer without zero sequence blocking

Amic Voltage Restorer (DVR) is a power electronic device to protect sensitive loads from voltage sag. Commonly, sensitive loads are electronic-based devices which generate harmonics. This paper presents fuzzy polar based DVR as voltage sag restorer and harmonics compensator without zero sequence blocking. Research presented in this paper uses d-q-0 axis method considering of the value of neutral axis, because the method works very well if the neutral axis value is zero. Result shows that this method can compensate voltage sag with a compensation error of 0.99%. Using this method, DVR may reduce voltage THD from 10.22% to 0.66%.