Stability and control of wind energy integrated power systems

This thesis presents an investigation of both small-signal and transient stability and control of doubly fed induction generator based wind turbine systems to enhance the stability performances of the connected power grid. First, the investigation of critical parameters of the grid-connected wind turbines to design a pitch-angle controller using LQR control method is conducted. Second, a robust simultaneous pitch-angle and reactive power control strategy by using H∞ constrained linear quadratic Gaussian control method is developed. Third, the coherency identification and clustering of wind turbines is researched using principal component analysis, agglomerative hierarchical clustering algorithm and Q-V analysis. Fourth, an optimal robust decentralized reactive power control design algorithm for the DFIG clusters using SMES device using a mixed H2/H∞ control method is established.