Improvement of power quality using a hybrid UPQC in renewable energy

In this paper a reduced rating star-connected transformer based Unified Power Quality Conditioner (UPQC) has been proposed for power quality improvement in wind energy source. This work comprises of a three phase three wire UPQC, a star connected transformer and a LC filter. This hybrid approach significantly improves the performance of UPQC under unbalance source voltage condition. The UPQC adopted to compensate current and voltage-quality problems of sensitive loads and Suppressing the load current harmonics under distorted supply conditions. The UPQC consists of a shunt and series converter having a common dc link. The dc link control strategy is based on the fuzzy-logic controller. The proposed solution has been analyzed and described, and a model of a 500-kV A wind energy source is considered. The extensive simulation results have been carried out in MATLAB/Simulink environment power system blockset toolboxes. From the results it has been shown that hybrid UPQC achieves superior capability of mitigating the effects of voltage sag/swell and suppressing the load current harmonics under distorted supply conditions.