Wind-storage Coordination Control Strategy for Improving Secondary Frequency Drop

In a high penetration wind power system, the direct withdrawal of the wind turbine from the frequency regulation may cause a serious secondary drop in frequency, posing a potential threat to the safe and stable operation of the grid. To this end, in this paper we propose a wind storage coordination control strategy aiming to improve the situation of secondary frequency drop. First, by employing the strategy, the turbine output power curve is improved, so as to enable the turbine to assume a dominant frequency regulation role and limit the power deviation caused by the withdrawal of the turbine from frequency regulation. Secondly, the exponential recovery type of energy storage power curve is designedfor frequency regulation, aiming to give full play to the fast regulation characteristics of energy storage and mitigate the impact of wind turbine withdrawal from frequency regulation on the system frequency. Finally, a two-area system model is built in DIgSILENT/PowerFactory software, and the simulation results verify the effectiveness of the strategy in this paper. The results demonstrate that the strategy can mitigate the system power deficit by limiting the turbine power dip value. Additionally, with the rapid regulation of energy storage, it can significantly enhance the frequency secondary drop of the system.