The basic idea of this research project is to analyze the voltage sag compensation capabilities of parallel full scale inverters of renewable power generating units. Further the interactions in a power generating system consisting of several power generating units due to balanced and unbalanced voltage sags are examined.[read more]Due to the connection of the power generating system to the power system the interactions with the power grid are also under investigation. Subsequently, strategies are developed to increase the transient stability of the power generating system and the power system and dampen oscillations caused by voltage sags. Under extermination are different control strategies and synchronization methods of the inverters to improve the transient response. In addition the differences caused by various grid configurations and parameters are investigated.