| In the active distribution network environment,the high permeability distributed power supply is connected to the distribution network,and the intermittent characteristics of the output bring great load fluctuation and voltage quality problems to the system.Considering fully the output of distributed generation,the allocation of access location and capacity of distributed energy storage system is carried out,and the optimal scheduling of energy storage system is also considered.Taking the operation cost,voltage deviation,active power regulation and other objectives of distribution network as objects,the energy storage system is developed using the improved lion swarm algorithm proposed in this paper.The main work of the optimization research of the unified two-tier model is as follows:(1)Firstly,the research status of energy storage system optimization is discussed,the different types of energy storage technology are introduced,and the basic principles of mechanical energy storage,electromagnetic energy storage and electrochemical battery energy storage are expounded.According to the charging and discharging characteristics of energy storage system,the power flow calculation model is analyzed and processed.Combining with the access of energy storage system to distribution network,the voltage distribution and loss variation of the system are theoretically deduced,and the corresponding optimization analysis is needed in the practical application process.The power flow calculation method of distribution network is analyzed,and the flow of forward and backward power flow calculation is given.(2)Secondly,aiming at the application and development of swarm intelligence algorithm,this paper focuses on the analysis of lion swarm algorithm,introduces the basic principle and operation steps of lion swarm algorithm,and carries out the global convergence analysis combined with the basic functions of lion swarm algorithm.In order to overcome the shortcomings of the selection operation in the basic lion swarm algorithm,an improved lion swarm algorithm combined with the selection of immune concentration isproposed according to the idea of artificial immunity.The basic lion swarm optimization algorithm,particle swarm optimization algorithm and improved lion swarm optimization algorithm are compared by simulation.(3)Thirdly,the effect of energy storage system on peak-shaving and valley-filling of distribution network is analyzed,and the active power regulation ability of distribution network is improved through the access of energy storage system.A two-tier mathematical model for optimal allocation of energy storage system is established.In view of the investment cost of energy storage devices,considering the loss cost of distribution network,the cost of purchasing electricity from upstream power grid,and the voltage deviation,an upper location and capacity selection model for energy storage system access is constructed.Peak filling and valley filling benefits,active power regulation capability,the lower optimization model of energy storage system is established.(4)Finally,aiming at the multi-objective optimization function problem,the ideal point method is adopted to transform it into a single objective function,and the optimal operation flow of energy storage system based on improved Lion Swarm algorithm and double-level optimization model is given.The proposed model and method are validated for an IEEE33 node system with distributed power.The results show that the proposed model and method are valid.With the optimal access of energy storage system,the power of distributed energy storage device can be adjusted and optimized,which can not only effectively improve the voltage quality,but also ensure the economy of the system. |
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