Research On Weak Robust Optimization Configuration Of Hybrid Energy Storage Capacity In New Energy Station

With the large-scale access of wind and solar resources,the clean energy penetration rate and load peak-valley difference of China’s power grid are increasing day by day.The scale of new energy stations is expanding,and its position in the power grid is increasingly important.However,the randomness of wind and solar output has brought more severe challenges to the economy and security of the power grid.As one of the key supporting technologies to promote the low-carbon transformation of energy,support the large-scale development and utilization of new energy and the construction of new power system,energy storage technology can effectively solve the problem of new energy output grid connection,which plays an important role in the safe and stable operation of power system.Based on the above background,this paper carried out the following research work:Firstly,this paper takes the new energy station and energy storage equipment as the research object,and introduces the operation characteristics respectively.Lithium battery and super capacitor are selected as hybrid energy storage,and the actual service life of the energy storage system is obtained according to the charging and discharging characteristics of energy storage.Secondly,a new intelligent algorithm,salp swarm algorithm,is introduced.In order to make up for the shortcomings of the algorithm,which is easy to fall into local optimum and has low convergence accuracy,a multi-strategy improved salp swarm algorithm is proposed.The improved algorithm is simulated and calculated,which lays the foundation for the subsequent model solution.Then,the improved algorithm is used to optimize the decomposition layer K and penalty coefficient a of variational mode decomposition,improve the mode mixing problem caused by improper parameter selection,and reasonably decompose the fluctuation power of tie line.Based on the working characteristics of hybrid energy storage,the optimal configuration model of hybrid energy storage capacity for new energy stations is established.The cyclic iteration method is used to find the boundary point of high and low frequency power modes that minimize the cost of hybrid energy storage configuration,and the most economical hybrid energy storage configuration scheme is obtained.In order to test the validity of the model,the actual data are analyzed.Finally,considering the uncertainty of wind and solar output and load demand,a bi-level optimal configuration model of energy storage capacity is established based on weak robustness theory,so that the configuration scheme can better cope with the random fluctuation of external environment.For the constraints with uncertain parameters,the robust equality transformation method is used to transform them into deterministic constraints that are easy to solve.The outer layer of the model aims at minimizing the comprehensive cost of the energy storage system after certain wind curtailment,light curtailment and load shedding.The inner layer aims at minimizing the equal annual configuration cost of the hybrid energy storage.The improved salp swarm algorithm is used to optimize the model,and the economic optimal hybrid energy storage configuration scheme considering the fluctuation of wind,light and load is obtained.It can be seen from the experimental results that the weak robust optimization model established in this paper not only considers the uncertainty of wind,light and load,but also has more practical significance in engineering.It also improves the over-conservativeness of the original robust model when solving,and improves the overall economy of energy storage in new energy stations with less penalty cost.