Optimal Sizing and Operation Strategy for Hybrid Energy Storage Systems Considering Wind Uncertainty

This paper presents a spectrum analysis-based method to calculate the optimal sizing and operation strategy for a hybrid energy storage system (HESS) combining batteries (BT) and supercapacitors (SC) to integrate high penetrations of wind power into the power grid. BTs and SCs have different response times and energy densities, which can be used to complementarily compensate the generation-demand imbalance. In this paper, the unbalanced power is first converted from time domain to frequency domain by discrete Fourier transform (DFT). Then upper and lower cut-off frequencies are determined to calculate the optimal sizing for each energy storage source. Moreover, a chance-constrained programming model is established to explore the optimal operation strategy for HESS. The model is solved by Monte Carlo simulation and a genetic algorithm. Simulation results on a practical system demonstrate that the proposed method can effectively reduce the ESS investment cost and maximize the economic profits.