Research On Optimal Capacity Allocation And Two-stage Operation Decision In Spot Market Of Microgrid With Electric Vehicles

With the increasing penetration of renewable energy sources such as wind and light,and the massive access of electric vehicle charging loads,the safe and stable operation of the grid will face huge challenges.The random fluctuation of wind and solar power generation and the randomness of electric vehicle charging loads will have a huge impact on the grid.Microgrids,as an important way to consume clean energy and smooth out load fluctuations,are of great significance to the clean energy transformation of traditional grids.On the one hand,in the pre-planning stage,the optimal allocation of micro-grid capacity is an important prerequisite to ensure the reliability of system power supply and operational economy.On the other hand,in the operation and dispatch stage,the optimal regulation of the capacity of each unit in the microgrid is also important to improve the economic and stable operation of the system,considering the microgrid as a trading entity in the context of the spot market.Therefore,in order to ensure the economic and reliable operation of microgrids,this paper focuses on the capacity allocation and optimal scheduling of microgrids containing electric vehicles,with the main research content as follows:(1)The basic connotation and structural characteristics of microgrid are summarized,the integration mode of electric vehicles suitable for microgrid is discussed,on this basis,the output characteristics of uncertain random microsources such as wind and light and controllable microsources such as diesel generators and the charging law of electric vehicles are analyzed,and the power output model and load model are constructed according to the characteristics of different modules of microgrid,which lays a theoretical foundation for the subsequent chapters to study the two-stage optimal operation decision of microgrid system capacity optimization configuration and spot market.(2)Taking the daily comprehensive cost and renewable energy absorption rate of microgrid as the optimization goal,taking the installed capacity of renewable energy generation units and the charging and discharging of electric vehicle energy storage batteries as constraints,the optimal allocation model of wind,solar and storage capacity of microgrid is established,and a capacity optimization allocation calculation method based on improved differential evolution algorithm is proposed.By comparing the microgrid capacity allocation examples with or without electric vehicles participating in dispatching,it can be found that the participation of electric vehicles in dispatching can significantly reduce the demand for capacity allocation,improve the peak shaving and valley filling capacity of microgrids,reduce the allocation of wind,solar and storage capacity by 16.7%,1.82% and 33.3%,respectively,and increase the utilization rate of renewable energy by 3.44%.The daily comprehensive cost of microgrid also decreased from 10103.41 yuan to 9221.25 yuan,indicating that the orderly charging of electric vehicles and participating in microgrid dispatching is an important way to reduce redundant investment in microgrid and improve the utilization rate of renewable energy.(3)Taking the predicted power of new energy power generation and the predicted electricity price of spot market as random variables,a two-stage optimization scheduling model of microgrid based on random opportunity constraint programming is constructed,and the random variables in the model are processed by stochastic simulation technology,and a particle swarm algorithm suitable for solving the model is proposed.The simulation results show that the maximum fluctuation of the two-stage planned power purchase curve is only 8.05 k Wh,which can effectively avoid the potential risks of the spot market,and after the implementation of demand-side management,the maximum power consumption per unit period of users is reduced by277.47 k Wh and the minimum electricity consumption is increased by 150.89 k Wh,and the load curve is optimized,which reduces the difficulty of microgrid peak shaving,strengthens the reliability of power supply,and provides a basis for decision-makers with different risk appetites participating in the electricity spot market to formulate twostage optimal dispatch plans for microgrids.