Abstract

The design and implementation of a new control system for reactive power compensation and mechanical torque, voltage regulation and transient stability enhancement for wind turbines equipped with fixed-speed induction generators (IGs) in power systems is presented in this study. The designed optimal linear quadratic regulator (LQR) controller provides an acceptable post fault performance for both small and large perturbations. Large disturbance simulations demonstrate that the designed controller enhances voltage stability as well as transient stability of the system during low-voltage ride-through transients and thus enhances the LVRT capability of fixed-speed wind generators. Further verifications based on detailed time-domain simulations are also provided. Calculations, simulations and measurements confirm how the increased STATCOM rating can provide an increased transient stability margin and consequently enhanced LVRT capability. A concept of critical clearing time has been introduced and its utility has been highlighted.