Study On The Smooth Up Wind Farm Output Fluctuation By Energy Storage System

With the global energy and environment issues have become increasinglyprominent,wind power as a clean&renewable energy, its global reserves is extremelyrich, wind power can improve the structure of world’s energy supply and ease the globalenergy shortage and environmental pollution problems, make an important contributionto the sustainable development of human society. However,with increasing scale ofgrid-connected wind farms, the effect of wind power randomness and volatility topower system become more and more obviously. Large-scale wind power bring a greatimpact on grid security, stability and dispatch, if these problems can not effectivelyaddressed, it will not only endanger the safe and stable operation of the grid, but walsolimit large-scale wind power developments.To stabilize the grid-connected wind farm output power fluctuations, reduce theadverse effects to power system. This paper purposes a new wind power generationsystem based on double-fed wind power generation and centralized configurationenergy storage system. The strategy of stabilizing wind output power fluctuations, themethod of power and capacity of energy storage systems selection, hybrid energystorage system coordination control were studied.Firstly, strategies of grid-connected wind farm output power fluctuations stabilizewere given respectively according to the two different requirements of the wind farmoutput power by power systemStrategy one aimed at reducing the grid-connected wind farm output powerfluctuations, analyzed the relationship between effect of suppression and time constantbased on low-pass filter algorithm, presented a new method of time constant choice,storage power and capacity algorithm based on the normal distribution, that is to designthe size of the energy storage device under the premise of meeting the standard for windpower integration, using the actual wind farm data to analytical validation.Strategy two planned the sub-period upper limit of the wind farm output poweraccording to wind power prediction,wind farm output power in upper limit value withenergy storage system.Analysed strategy of wind farms and energy storage systemscoordinated operation to optimize the output,discussed the impact of the differentdivided period on the storage size and storage capacity, energy capacity obtainedaccording to the full year data of wind farm. Secondly, proposed a hybrid energy storage system to smooth wind farm outputpower fluctuation combined the characteristics of super capacitor and battery energystorage.Designed the coordination and control of hybrid energy storage system.Analysed the super capacitor energy storage unit to enhance the power of the hybridenergy storage system output and optimize battery energy storage unit tocharge-discharge power, and reduce the number of charge-discharge cycles.