Flicker attenuation and transfer study for induction generator integrated into distribution network

Squirrel-cage induction generators (IGs) are widely used in distributed generation (DG). When the voltage at the point of common coupling is fluctuant, the embedded IG will show the impedance characteristic with dynamic changes under the different fluctuation frequencies. In addition, the drive train of IG set has great impact on the voltage flicker attenuation. This paper observes the dynamic response of IG to the voltage flicker through the experiments and further defines the flicker attenuation factor and transfer coefficient. A linearization model of IG with two-mass equivalent drive train is constructed through comparing the impacts of different drive trains (such as diesel engine, wind turbine) on the voltage flicker attenuation. Then an analytical method is proposed to determine the dynamic impedance, attenuation factor, transfer coefficient and flicker limit for IG integrated into distribution network. The correctness of the proposed method is verified by the experimental tests and the dynamic simulation using the detailed model of IG set. The parameters sensitivities of drive train and generator to the voltage flicker attenuation effect are analyzed and discussed in the paper.