Research on the capacity configuration of the "flywheel + lithium battery" hybrid energy storage system that assists the wind farm to perform a frequency modulation

In order to reduce the adverse impact of wind power fluctuations on the primary frequency modulation of the grid, based on the operation data and frequency modulation performance of the wind farm power generation equipment, the analysis is carried out, and combined with the characteristics of the "flywheel + lithium battery" hybrid energy storage system, a random time delay hybrid system is constructed. Using wavelet packet to decompose wind power grid-connected power, decoupling lithium battery energy storage and flywheel energy storage components. In order to achieve the goal of maximizing the net present value (NPV), the minimum average annual energy storage cost is taken as the objective function, and the pattern search method based on the Hooke-Jeeves method in the direct search method is used to solve the problem. The simulation results show that the research can ensure the frequency modulation performance of the wind farm-energy storage hybrid system, and at the same time determine the wind farm supporting energy storage capacity based on economic optimization, and the configuration of flywheel energy storage and lithium batteries in the hybrid energy storage system to improve the overall economic benefits of the system.