| At present,China is in the critical period of achieving the "double carbon" target and promoting low-carbon energy transition,wind power is an important part of the future energy structure because of its good economy and environmental protection,but the intermittent and random nature of wind power reduces the friendliness of grid connection.As a new type of energy storage of power system,hydrogen energy storage has the advantages of clean and green,high energy density,and the hybrid energy storage system coupled with wind energy and hydrogen energy is one of the effective ways to solve the above problems,electrochemical energy storage has a fast response speed,using it to smooth out the power fluctuations caused by the response delay of hydrogen storage is one of the effective candidates,electrochemical energy storage combined with the structure of hydrogen storage has become a typical energy storage configuration in the wind-hydrogen hybrid energy storage system,the study of reasonable capacity optimization configuration to meet the load demand in different scale scenarios,while taking into account the system economy,safety and reliability,is of great significance to build a new power system,realize multi-energy interconnection and construct energy internet.Firstly,based on the analysis of the working principle of wind-hydrogen hybrid energy storage and the operating characteristics of each part,a hybrid energy storage system consisting of alkaline electrolyzers,high-pressure gaseous hydrogen storage tanks,proton exchange membrane type fuel cells and batteries is constructed.In order to achieve power smoothing on the grid,a wind power distribution method based on the variational modal decomposition algorithm is proposed.Comparing the performance of the empirical modal decomposition algorithm in power smoothing,it is verified that the variational modal decomposition algorithm can avoid spectral overlap and has higher decomposition accuracy,which can better decompose the original wind power into hybrid energy storage power tasks and grid-connected components that meet the fluctuating quantity limits.Secondly,to address the problem of intermittent operation of the electrolyzer due to wind power fluctuations,the hydrogen production efficiency characteristics of the electrolyzer are studied,whereby the optimal working interval of the electrolyzer is evaluated,the power allocation strategy of hybrid energy storage units is formulated by combining the constraints of electrochemical energy storage charging and discharging characteristics,the reliability indexes of power fluctuation rate and energy shortage rate are proposed,and a multi-objective capacity allocation optimization model with the lowest comprehensive cost and the smallest reliability index is established.Once again,an improved Non-Dominated Sorted Genetic Algorithm-Ⅱ(NSGA-Ⅱ)with elite strategy is proposed to overcome the problems of traditional NSGA-Ⅱ,such as the tendency to fall into local optimality,and improve the performance of the algorithm in finding the best.The feasibility and effectiveness of the improved NSGAⅡ algorithm in solving multi-objective optimization problems are verified by conducting simulation analysis based on the test functions and combining the algorithm performance metrics.Finally,an arithmetic analysis is performed based on the actual measured wind speed data of a wind farm in Inner Mongolia,combined with the energy storage unit power allocation strategy,the multi-objective capacity allocation optimization model is solved using the improved NSGA-Ⅱ algorithm,and the optimal solution for the capacity allocation of hybrid energy storage units is obtained based on the fuzzy affiliation function.The simulation results show that the economic and reliability indexes are reduced after the optimization,and the developed energy management strategy can ensure the safe and efficient operation of hydrogen and electric energy storage devices. |
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