Frequency Regulation and Control of Grid-Connected Wind Farms Based on Online Reduced-Order Modeling and Adaptive Control

This article presents a frequency regulation and stabilization control architecture for a wind turbine generator (WTG) integrated power grid, which can be added to existing WTGs. The architecture uses online reduced-order modeling of the power grid with frequency-dependent network equivalent that can seamlessly evaluate the grid fluctuations with respect to the point of common coupling of the wind farm. Then, an adaptive control architecture with the help of an online identification routine is used to balance the torque control of the wind generator (here doubly fed induction generator is considered) such that the frequency of the system is balanced. The main advantage of the proposed architecture is that the approach ensures frequency stability during grid oscillations at any location due to grid-related or WTG-related problems. The proposed approach not only maintains the frequency within acceptable limits during oscillations, but also makes sure that voltages are at normal values. The approach can work without wind speed measurements. The architecture is evaluated using wind-farm-integrated Kundur two-area and IEEE 39-bus test systems using a real-time digital simulator.