Aggregation frequency response modeling for wind power plants with primary frequency regulation service

Abstract

High-penetration wind power access to grid requires wind turbine generator (WTG) to provide frequency regulation service. Consequently, the frequency dynamics of wind power plants (WPPs) integrated system are changing; thus, it is necessary to investigate the dynamic frequency response of WPPs. In this paper, an analytical approach for an aggregated frequency response model for WPPs with primary frequency regulation service is presented and validated. First, different operation region of WTGs is fully taken into account, and a low-order wind power frequency response (WPFR) model with combined frequency control is deduced based on small signal analysis theory, which has been given in the form of symbolic transfer function. Afterwards, a system identification (SI) analytical method is proposed to aggregate a multi-machine WPFR model with heterogeneous parameters into a single equivalent model, which is called an aggregated WPFR (AWPFR) model, and this aggregation method is validated by the mathematical proof. Finally, the accuracy and effectiveness of the AWPFR model is verified through comparisons of simulation results obtained from the multi-machine WPFR model, detailed wind power plant (WPP) model and individual WPFR models, and the impact of the WTG parameters on the system frequency characteristics is analyzed and discussed. Such an aggregation model can provide a convenient way to describe the dynamic frequency response of WPPs by avoiding the need for modeling complex transient processes while maintaining a satisfactory level of accuracy.