| Energy transformation is an important way to solve the problem of excessive greenhouse gas emissions,and it can also improve the current situation of over-reliance on traditional fossil energy.With wind power occupying an increasingly important position in the power grid,the frequency stability problem caused by its output uncertainty becomes more and more obvious.Based on the background of high proportion wind power access system,a random fuzzy model is established by this paper to analyze the impact of high proportion wind power access on frequency regulation and the ways of energy storage to improve frequency regulation.To this,the following works are done in this paper:Firstly,the probability distribution analysis of the regulation demand of AGC(Automatic Generation Control)with wind power system is carried out,and the parameters of the probability model are counted to get the fuzzy form of the parameters,and the random fuzzy model is established.Combining the randomness and fuzziness to describe the uncertainty of the frequency regulation of wind power system.Then,based on the random fuzzy model,the AGC regulation capacity demand under different wind power permeability is estimated..Then,in order to alleviate the influence of wind power fluctuation on frequency modulation,energy storage is allocated in two-area interconnected AGC simulation system,step disturbance and continuous wind power disturbance are added to the system respectively.The frequency simulation results with or without energy storage are compared.The comparison of numerical examples shows that energy storage has goog effect on improve frequency regulation both under step disturbance and continuous wind power disturbance.Finally,after proving that energy storage can effectively improve the frequency regulation capability of the system,optimizing the allocation of energy storage capacity.Through EMD(empirical mode decomposition),the AGC random fuzzy frequency regulation requirement is decomposed into eigenmode components of different frequency bands.The AGC frequency regulation requirement is decomposed into high frequency and low frequency components with each eigencomponent as the boundary.The high frequency components are allocated to energy storage.The low frequency components are assumed by traditional units,and the corresponding energy storage capacity is obtained.By comparing the frequency regulation indexes under different demarcation conditions,the optimal energy storage capacity is determined.A random fuzzy model of AGC frequency regulation demand for wind power access system is established by this paper,formulates strategies for energy storage to participate in frequency regulation and methods for determining energy storage capacity,fully takes into account the uncertainty of wind power,which can provide a reference for the configuration of wind power system to improve frequency regulation. |
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