Sizing Optimization of Wind-Hydro Combination System Based on Frequency Division

With the shortage of fossil energy, wind energy has attracted people's attention increasingly. However, the intermittence nature of wind energy will lead to unstable power output, which may bring much challenge when wind power in integrated to grid. Thus, wind-hydro combination system which consists of wind farms and pumped storage power stations is established as one of the solutions to solve this problem. Due to high investment cost of energy storage system like pumped storage power stations, some improvements and optimizations of system capacity should be considered. In this paper, high-frequency and difficult-to-handle wind power are processed by the pumped storage power station and the remaining wind power are processed by conventional hydropower stations. Hilbert Huang transform(HHt) in this paper is used to decompose the wind power frequency. Then, 50 different capacities for two types of hydropower stations are calculated by genetic algorithm to improve the stability of integrated system output. The weight coefficient named OD(optimization design) is proposed to quantify the economy and stability of the combination system, which can understand the comparison of different capacity ratios in a clear way.