Decentralized control to augment LVRT capability of wind generators with STATCOM/ESS

The design and implementation of a new control scheme for reactive power compensation, voltage regulation and transient stability enhancement for wind turbines equipped with fixed-speed induction generators in large interconnected power systems is presented. The nonlinear behavior of wind turbines has been represented in this paper by an uncertain term, derived from the Cauchy remainder of the Taylor series expansion. A systematic procedure is proposed to design decentralized multivariable controllers for large interconnected power systems using minimax output feedback control design method and the controller design procedure is formulated as an optimization problem involving rank constrained linear matrix inequalities (LMIs). In this paper it is shown that STATCOM with energy storage system (STATCOM/ESS), controlled via robust control technique, is an effective way of improving the low-voltage-ride-through (LVRT) capability of fixed-speed wind turbines.