Effect of wind parks with doubly fed asynchronous generators on small-signal stability

This paper investigates modes of response introduced by wind parks with doubly fed asynchronous generators (DFAGs), as well as their impact on electromechanical oscillations in interconnected power systems. A DFAG model with detailed control loops is used, as it appears in the literature and commercial software. It is shown that under certain conditions and without appropriate controller tuning the voltage/VAR control loop of an interconnected DFAG tends to instability. Furthermore, the effect of increased penetration of DFAGs on the stability of inter-area oscillations in a small typical power system is examined. It is shown that the effect is generally favorable, but there are cases where the inter-area mode is less damped or can even be destabilized. Improved controller tuning to avoid instability in the latter case is proposed.