A Method to Identify the Impact of Wind Turbine Generator on Low-Frequency Oscillations

This paper develops a frequency-domain approach to study the impact of wind turbine generator (WTG) on inter-area low-frequency oscillations. A Heffron-Philips model of power system with WTG integrated is derived, it is found that the new model has similar configuration with the original one, which has a feedback control structure. On the basis of the new model, the impact of two critical factors on stability margin, the change of power output distribution and the dynamic interaction introduced by WTG, is identified. A minimum characteristic locus method, recently introduced by the authors, is extended to quantify the impact of the two factors. The proposed method is applied to the example New England power system and IEEE 118-bus test system. The results indicate that, after the integration of WTG, the stability effect caused by the change of power output distribution is much greater than the effect caused by the change of dynamic interaction.