Research On Control Strategies Of Hybrid Energy Storage For Smoothing Wind Power Fluctuations

Through smoothing wind power short-term fluctuations, the negative influenceof grid-connected wind power on the power system frequency modulation can beconstrained effectively. Restricted by physical conditions, a single type of energystorage medium is difficult to smooth wind power short-term fluctuations. With highcycle times, high power density and high energy density, hybrid energy storagesystems composed of multi-types of energy storage medium can smooth wind powerfluctuations effectively. It is the key to select the configuration and design effectivecontrol strategies for hybrid energy storage systems, minimizing its cost whilemeeting the demand for smoothing wind power fluctuations.For hybrid energy storage systems composed of batteries and super capacitors, acontrol strategy smoothing power fluctuations based on low-pass filter is designed.Considering the working status of energy storage systems, reference power ofbatteries is determined on the basis of the principle of sliding average, realizingbatteries controlling the trend component of wind power fluctuations and supercapacitors smoothing the fast varying component of wind power.Configuration methods of hybrid energy storage systems to minimize the cost isdesigned. Considering characteristics of energy storage medium, a mathematicalmodel to calculate the annual cost of hybrid energy storage systems based on lifecycle cost is established. Methods to select optimal control parameters andconfiguration to minimize the annual cost is studied.With simulation analysis based on operation data of a wind farm, effectivenessof the control strategy designed is verified. The influence of the relevant operationalcontrol parameters on the technical and economical index of hybrid energy storagesystems is analyzed, then optimal control parameters and configuration results areachieved.Based on the research of hybrid energy storage system control strategies and configuration methods, a wind-storage networking operation platform is built in theenvironment of Visual Studio and SQL sever. Management and analysis of wind/loaddata are realized, providing a visual operation platform for analyzing operationperformance and configuration of energy storage systems.