Research On Energy Optimal Dispatching Strategy Of Microgrid Considering The Flexibility Of Electric Vehicle

With the global energy shortage and environmental degradation,the microgrid is widely used for its outstanding advantages of environmental protection and reliability.At the same time,the number of electric vehicles,which conform to the concept of energy-saving and low carbon,is rising,and the technology of vehicle to grid has become popular research.However,due to the dual source-load characteristics of electric vehicles and the random nature of their charging behavior,a large number of electric vehicles charging centrally will have a certain impact on the safe and economic operation of the microgrid.Under the prospect of high penetration of electric vehicles integrated into the grid,this thesis explores in depth the problem of optimal scheduling strategy for flexible charging and discharging of electric vehicles involved in microgrid operation.In this thesis,a mathematical model is established for the studied microgrid for each generation unit,load,and electric vehicle,and the return time,departure time,and driving mileage of electric vehicles are fitted stochastically using the Monte Carlo method,and the negative impacts of disorderly charging of electric vehicles on the microgrid are analyzed,such as intensifying the load peak and unfavorably improving the operating revenue of microgrid,to make a theoretical pavement for the flexible charging and discharging of electric vehicles in the microgrid to participate in optimal dispatching.In view of the negative impact of disorderly charging and discharging of electric vehicles on the economics and stability of microgrid operation,a time-of-use tariff with four price gradients is developed,and a strategy is proposed to guide the orderly charging and discharging of electric vehicles and their participation in the optimal dispatching of microgrid with this tariff.The strategy can guide the electric vehicle users through the price to avoid concentrated charging at the peak of microgrid electricity consumption while bringing some economic benefits to the microgrid and improving the load curve.Through the solution,the analysis verifies the economic benefits and the improvement of the load curve of the microgrid operation when electric vehicles are involved in the dispatch.In view of the deviation between the declared value of power purchase from the microgrid to the superior grid and the actual interactive power,a multi-time-scale optimal scheduling strategy for the microgrid with the participation of electric vehicles is proposed,which is divided into two stages: day-ahead and intra-day scheduling,with the objective of optimizing the economic performance of the microgrid,adjusting the power output of controllable power sources,charging and discharging of energy storage systems and the use of demand response loads.The intra-day scheduling stage aims at minimizing the deviation between the declared power value of the microgrid and the actual interactive power,and adjusts the charging and discharging power of electric vehicles to reduce the deviation.By adjusting the deviation penalty factor,the power fluctuation range of the contact line can be effectively adjusted.By setting different comparison cases,it is verified that the strategy can ensure the economic operation of the microgrid as well as the reliability and stability of the microgrid operation.The optimal scheduling strategy of microgrid proposed in this thesis considers the schedulable flexibility of electric vehicles in time,further improves the reliability of microgrid operation by invoking their charging and discharging power,and reduces microgrid operation cost,improves economic efficiency,and promotes the development of microgrid industry.