| With the proposal and implementation of the "Double Carbon" policy,electric vehicles with low pollution and high energy conversion rate have become an urgent development trend in the future transportation end,and comprehensive consideration of the collaborative optimization and dispatch of electric vehicles and new energy in the distribution network has become an important research direction.At the same time,the centralized disorderly charging of large-scale electric vehicles in the city brings huge power supply pressure to the distribution network,affecting the stable and economic operation of the distribution system,and reasonable guidance for the orderly charging and discharging of electric vehicles can not only play a smooth load curve fluctuation,but also effectively reduce the role of user charging costs.Therefore,in order to improve the power quality of electric vehicles and photovoltaics after they are connected to the distribution network,this paper establishes an evolutionary dynamic game model of the supply and demand side in the distribution network and formulates the corresponding orderly charging strategy of electric vehicles.The research content of this paper is as follows:1.Summarize the theoretical basis of electric vehicle charging load prediction and analyze the characteristic indicators of its impact on the distribution network.Firstly,taking the electric private car with one charge per day as the research object,the data fitting of the starting charging time,charging time and mileage is based on the residents’ travel statistics,and the Monte Carlo random sampling method is used to simulate the influence of disorderly charging of electric vehicles on the peak-valley difference of the load curve of the distribution network.Then,the influence of disorderly charging of electric vehicles on the peak-valley difference of the load curve of the distribution network is simulated by example.Finally,three quantitative indicators affecting the stable operation of the distribution network when electric vehicles are connected to the grid are summarized.2.In order to alleviate the voltage offset caused by the electric vehicle being connected to the distribution network,this paper proposes a charging and discharging guidance scheme for EVs based on the improved alternating direction multiplier method considering the voltage limitation of the distribution network node and the interests of electric vehicle users.The electric vehicle charging model is established by graph theory and convex optimization theory,and the multivariate problem of adjusting the charging power of electric vehicles in multiple periods in multiple periods is transformed into a univariate multiple sub-problem by ADMM method,and the YALMIP toolbox and SEDUMI solver are used to obtain the solution.The example results reveal that the proposed strategy can decrease the charging cost of users while slowing down the voltage offset of nodes.3.Aiming at the three-phase imbalance caused by the integration of electric vehicles into the grid,this paper considers the conflict of interests between the distribution network and the supply and demand sides of electric vehicles,and proposes an optimization strategy for charging and discharging of electric vehicles based on evolutionary dynamic game.Introducing photovoltaic units to further improve the cleanliness of electric vehicle electricity consumption,taking user charging costs and three-phase load curve fluctuations as objective functions,and establishing an evolutionary dynamic game model in which electric vehicles and photovoltaic units are nomad populations and basic building loads are sedentary populations clusters.Taking the distribution network of a commercial area as the simulation scenario,the calculation results show that the proposed strategy reduces the charging cost of users,reduces the three-phase imbalance of the load curve,and meets the needs of reactive power compensation,which ensures the stable operation of the distribution network. |
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