The design and implementation of a new control scheme for reactive power compensation and voltage regulation in the transmission system, as provided and controlled by a wind park is presented. It proposes an optimal tracking secondary voltage control scheme applied to doubly fed induction generator-based wind generators. The ability of the controller to regulate transmission network voltage profiles is demonstrated and compared with primary voltage control, an alternate secondary voltage control approach, and the voltage profile obtained from optimal power flow analysis. The dynamic performance of the controller is also validated in response to system contingencies, namely short circuits. The impact of communication time delays and of the short-circuit ratio on the dynamic performance of the voltage controller are considered. Results show that the controller properly regulates the voltage in steady state and performs properly during transients resulting from short circuits. Decoupling between primary and secondary loops should be applied to mitigate the effects of the time delay.