Improving Frequency Stability with Inertial and Primary Frequency Response via DFIG Wind Turbines equipped with Energy Storage System

Renewable Energy Sources (RES), and especially wind turbines (WT) as the most mature technology, will provide a large share of energy generation in a future sustainable power system. This development introduces several challenges that need to be addressed in order to ensure a safe transition away from the fossil-fuel based generation. One of the segments where RES will have a major impact is ancillary services, such as frequency support. Until now, RES (Wind & Solar) did not participate at frequency regulation of the system, which will change as their numbers in the grid increase. The contribution of this paper is the investigation of the system impact of wind generation, when wind turbines are equipped with a control system that provides frequency related ancillary services. More specifically, we analyze primary frequency response and inertial response in the case when Doubly Fed Induction Generator (DFIG) wind turbines are equipped with Energy Storage Systems (ESS). The results are presented for different levels of RES penetration and different levels of ESS deployment.