The Study On Control Strategy Of The Stabilize Fluctuating Wind Power Based On Hybrid Energy Storage

In order to effectively suppress wind farm output power volatility and randomness, the wind farm will need a combination of both with the energy storage system, which can reduce the adverse effects due to fluctuations in the power output of wind farms and on the grid, because the mixing reservoir energy systems while both an energy storage device and power advantages of energy storage device type, this article focuses on the wind power fluctuations based on mixed storage of stabilizing control strategy.Through the analysis of the wind farm fluctuation characteristics of output power, combined with the structure and characteristics of hybrid energy storage system, this thesis proposes a method of wind power fluctuation stabilization which is based on wavelet packet decomposition and State of Charge(SOC) hierarchical optimization of hybrid energy storage. Main research is as follows:(1) A study of hybrid energy storage system structure, that is consist of super capacitors and lithium battery is conducted, the structure and working principle of hybrid energy storage system is analyzed. According to characteristics of each energy storage device a relevant equivalent circuit model is established, and further research on the characteristics of hybrid energy storage system is conducted, and finally the relevant parameter index of lithium batteries and super capacitors are obtained.(2) Based on the wind power data which is timely measured, the impact of fluctuations in the characteristics of wind power output and the different bands fluctuations on the grid frequency are analyzed, and the main objected spectrum which is needed to be flatted and restrained by power energy storage systems. Muti-scale decomposition of wind output power is conducted by using wavelet packet decomposition theory, and real-time data of each frequency range after wavelet package decomposition is obtained.(3) According to the realtime data of wind power and model of hybrid energy storage, detail amount of capacity and power of lithium batteries and supercapacities which is needed in this thesis is determined by using genetic algorithms based on the wind farm optimization practicality and economy.(4) Focusing on the entire intelligence of charge and discharge of hybrid energy storage system in the process of wind power to stabilize and SOC regulation problem on different storage devices, this thesis does research on stabilizemethod of wind power on hybrid energy storage based on layered optimazition of SOC. This method includes power optimazition layer and power distrubtion layer. Power optimazition calculates the desired power of dynamicly regulative storage system based on the entrie current SOC states of hybrid energy storage system; and power distribution layer conductes the distribution of power based on each SOC states and charge-discharge characteristics, in order to realize the coordinate control and rapid tracking to the setting power of SOC of storage devices.(5) Build a simulation model PSCAD, verify the validity of the hybrid energy storage system designed in this paper control methods. Simulation results show that: the control strategy studied in this thesis, completed a smooth control of the output power of the wind power fluctuations, and to maintain the overall mix of energy storage systems and energy storage device SOC within a reasonable range, effectively avoid overcharge and over discharge phenomenon It occurred, prolonging its life.