A method for optimal sizing hybrid energy storage system for smoothing Fluctuations of Wind Power

A hybrid energy storage system (HESS) is integrated with a wind farm to smooth out its fluctuations in order to reduce the impact on the grids. This paper presents a cutoff frequency method for optimizing the HESS for smoothing fluctuations of wind energy. The main goal of the proposed method is to find the rated power and capacity of HESS. Based on spectrum analysis results and power ramp rate, the best cutoff frequency, expected power and the minimum absorb power are determined. According to the characteristics of HESS and the safety specifications, the minimum sizing of the battery and the super capacitor were selected. The proposed method was verified based on historical wind power data and Chinese Standard of grid-connected.