Optimal Configuration And Operation Strategy Of Energy Storage Of Fast Charging Stations Of Electric Vehicles

The fluctuated charging power generated in the fast charging process of EV charging station will have a great impact on the operation of the distribution network it is connected to,so the corresponding compensatory measures should be considered from the perspective of charging station.The rational allocation of energy storage system(ESS)in fast charging stations can not only mitigate this impact,but also participate in auxiliary market services of distribution network to help the distribution network increase the utilization of clean random wind power output,which can not only generate economic benefits,but also eliminate the impacts of wind power volatility.Therefore,it is of great significance to optimize the ESS configuration in the fast charging station and study the optimal operation strategy of the energy storage system in the fast charging station under the random wind power access,for the planning and operation of the fast charging station and the operation and regulation of the distribution network connected to it.Based on the facts above,this paper firstly modeled and analyzed the typical uncertainty of the source and load side,wind power and charging load,and mined the random characteristics.On this basis,an optimal capacity allocation method for fast charging station ESS operation strategy of fast charging station energy storage considering the characteristics of charging load and wind power output fluctuation are proposed.The research work of this paper can be summarized as follows:(1)The model of uncertain wind power output and charging load of fast charging station is proposed.Aiming at the uncertain access of the wind power on the source side,the model is modeled by the scenario method to capture the typical wind power fluctuation characteristics,reduce the calculation amount while ensuring the accuracy of solution,and thus guarantee the solution efficiency of the established planning model.Aiming at the uncertainty of charging load on the load side,according to different ev characteristics and the probabilistic driving mode of ev owners,a modeling method for calculating the charging load demand of fast charging station was proposed to ensure the validity of the calculated value of charging load,and to support the research and analysis of the optimal configuration of energy storage and operation strategy of fast charging station.(2)A method for optimal allocation of energy storage capacity of fast charging station is proposed,which takes into account the characteristics of charging load and wind power output fluctuation.Taking investment cost,operation and maintenance cost,energy storage charging cost and discharging benefit,as well as curtailment penalty cost and life cycle cost minimization of energy storage battery as optimization objectives,an optimization configuration model was established.The impact of random characteristics of wind power is reflected by curtailment penalty cost and the fluctuation of charging load is reflected by operating cost of energy storage.In order to improve the efficiency of the model,the nonlinear part of the objective constraint is processed by piecewise linearization and converted into mixed integer linear programming model.An improved IEEE-33 node system is used to test the configuration results of different energy storage types,and the influence of different DG permeability and different EV on ESS configuration results and economic benefits is analyzed to verify the feasibility and effectiveness of the model.(3)An economic optimization operation strategy of energy storage system of fast charging station for electric vehicles ispropose.This strategy aims to minimize the operation cost,comprehensively considers the operation cost,wind abandoning cost,network loss cost and energy storage and discharge benefits,and according to the charging load data and Time-of-Use electricity price obtained in the preceding chapter,gives the energy storage charging and discharge strategy of fast charging station,and verifies the effectiveness of this strategy through IEEE-33 nodes system.The results show that the strategy can reduce the peak load of EV charging stations,smooth the charging load curve,improve the voltage level of nodes in the network,and improve the economic benefits of fast charging stations.