A control method for increasing reactive power generation of a wind turbine having a Doubly-Fed Induction Generator (DFIG) includes obtaining, by a control device having one or more processors and one or more memory devices, wind forecast data of the wind turbine. Further, the method includes generating, by the control device, a real-time thermal model of the DFIG of the wind turbine using the wind forecast data. More specifically, the thermal model defines a thermal capacity for the DFIG that does not exceed system limits. Thus, the method also includes dynamically adjusting, by the control device, a reactive power set point of the DFIG of the wind turbine based on the real-time thermal model.