Fast Voltage Recovery Control of Wind Farm With Energy Storage Considering Coupling of Active Power and Voltage in Weak Grids

The weak grids containing wind power face a serious challenge: voltage recovery after faults is slow. Active power and voltage coupling (APVC) is one reason, but it has not yet been considered. Hence, this paper proposes a fast voltage recovery (FVR) control scheme for the wind farm with energy storage system (ESS). The coordination of the wind farm and ESS resolves APVC to obtain fast voltage recovery. Firstly, the APVC of the wind farm is quantitatively analyzed. As a key finding, the increase of active power output of wind farms during recovery has a negative coupling effect on voltage recovery. Moreover, the APVC is more significant in weak grids and low-voltage scenarios. Secondly, the FVR control based on preset curves is proposed, benefiting from the coupling analysis. In the early recovery stage with strong coupling, the ESS is coordinated to absorb active power. It transforms the negative effect of the coupling into a positive one to support voltage in priority. In the later recovery stage with weak coupling, the wind farm recovers active power with minimal effect on voltage. Finally, the results in two IEEE systems and real-time experimental platform verify the effectiveness of the proposed FVR control scheme.