| Fossil energy shortage and serious environmental pollution promote the rapid development of wind power,but the wind power output is random and volatile,and its large-scale network will endanger the safe and stable operation of the grid.Energy storage system has two-way power handling capacity,and it can achieve the power of space-time shift,and effectively suppress the volatility of wind power,and ificantly improve the capacity of the grid to accept wind power.However,through the quantitative analysis of the output characteristics of wind power,it can be seen that smoothing the fluctuation of wind power requires both fast power tracking and long cyclic life under frequent charge and discharge,and also requires large power level and big storage capacity.Single energy storage can not meet these requirements at the same time,so we need to use a variety of energy storage in order to make full use of the advantages of various types of energy storage.Based on the analysis of the fluctuation characteristics of wind power,this paper studies the influence of different power distribution methods on the energy storage capacity allocation.A method,which using the moving average and empirical mode decomposition(EMD)to obtain the energy storage reference power,about power and capacity allocation of hybrid energy storage system(HESS)is proposed.And then the HESS for smoothing the fluctuation is economically evaluated.This paper analyzes the essential causes of wind power fluctuation,establishes its quantitative index,and expounds the requirement of stabilization.Based on the measured data,the wind power output and its fluctuation characteristics are studied from the time domain and frequency domain respectively.The wind power output is random and fluctuating.With the time scale increasing,the volatility is enhanced.The low frequency fluctuation amplitude is higher,but the high frequency fluctuation amplitude is lower,and the wind farm cluster effect makes the wind power output smoother.Through the multi-angle comparison and analysis of various types of energy storage technology,a HESS for the "calm fluctuations" scene is built.The power allocation method of HESS which is based on EMD is studied and improved.Then a method based on sliding average method and EMD is proposed,and the configuration results of different power distribution methods are compared.The simulation results show that the grid-connected power obtained by this method is in agreement with the original wind power curve.The maximum fluctuation and volatility of the 1-minute and 10-minute time scales are the least,then the power and capacity are obviously below the margin of the grid and low-frequency grid method configuration results.Finally,the economic evaluation methods of electric power technology are introduced,and the HESS is economically evaluated by combining the dynamic investment payback period,internal rate of return and present value method.Based on the life-cycle cost theory,considering the benefits when the quantity of spinning reserve and transmission network decreases,the economic model of HESS is established,and the optimal configuration program is choosed under taking into account the economic indicators.The simulation results show that the hybrid scheme can significantly increase the cycle lif-e of lithium ion battery and greatly reduce the energy storage cost.The HESS composed of lithiumion and super capacitor is the most economical. |
PDF Full Text Request