Study of the Reactive Power Characteristics in the Double Fed Variable Speed Constant Frequency Wind Turbine

In order to improve the Grid-Connection of the wind turbine and the voltage stability of the power system, the study the reactive power characteristics (R.P.C) of the double-fed variable speed constant frequency wind turbine is vital. This paper adopts the equivalent circuit of the doubly fed induction generator (DFIG) to derive the equation of the reactive power balance. Based on the equivalent circuit, the paper discussed the relationship of the reduced reactive power (R.P) between the stator and rotor circuit with different frequency. All of those reveal that the DFIG has an enormous mechanism to adjust the reactive power flexibly. After studying the stator and rotor R.P.C of the DFIG , we summarized the influence of the rotor R.P from the slid ratio and the stator R.P. And the end, we verify the correction of theory by a simulation.