Energy capacitor system for DFIG-based wind farm transient behavior enhancement

This paper presents the advantages of the utilization of a small-sized Energy Capacitor System (ECS) in a power system including a Doubly Fed Induction Generator (DFIG) based wind farm. In order to show its impact in the transient behavior, the ECS was located in the terminal of the wind farm. A four-machine infinite bus system was considered. One of the units was considered as an aggregated model of DFIG-based wind turbines (WT). A three-phase to ground fault was applied to a nearby line and the WTs were considered protected by standard crowbar with converter fast reconnection system. The small-sized ECS shows a positive effect not only in the WT but also in the synchronous units, such as reduction in WT mechanical stress and power oscillations. Despite the limited energy storage capacity a reasonable power output smoothing was obtained. Results show an important improvement in the system transient behavior.