Bi-level Frequency Response Control Strategy Based on Wind Power and Energy Storage

When multiple wind farms and energy storage stations participate in frequency regulation, due to different operation conditions, there are certain differences in the cost of providing frequency regulation output. In addition, when the wind farm participates in frequency regulation, the fatigue load on the wind turbines in the wind farm will also increase, which will affect the operation safety of the wind turbines. In order to solve the above problems, this paper proposes a bi-level frequency response control strategy based on wind power and energy storage. It can reduce the total cost of frequency regulation and the total load in each wind farm by coordinating the output of the wind farms and energy storage stations and the wind turbines in the field while meeting the frequency regulation requirements of the system. First, the loss, degradation and risk cost of wind farms and energy storage stations during frequency regulation are analyzed and quantified, and the active power distribution control strategy of the station on the station coordination layer is established, while the lowest cost output plan of each station is determined. Then, based on the linear relationship between wind turbine output, wake fluctuation and fatigue load, an additive increase multiplicative decrease algorithm is adopted to build a decentralized active power control strategy for the wind farm on the unit coordination layer, which coordinates the output of the wind turbines. While maintaining the frequency regulation performance of the wind farm, the strategy can reduce the total load in the field. Finally, an IEEE RTS-79 bus system is built in MATLAB/Simulink, which contains two 100×5 MW doubly-fed wind farms and two 100 MW/100 MW·h lithium battery energy storage stations. The simulation verifies the effectiveness of the proposed strategy. © 2022 Automation of Electric Power Systems Press.