Research On Multi-time Scale Optimal Dispatch Of Microgrid Considering Source And Load Uncertaint

Under the background of "carbon peaking and carbon neutrality",vigorously developing distributed power supply has gradually become the consensus of the government and the public.As the advanced development stage of distributed power generation,microgrid can realize energy efficiency and cascade utilization by planning and dispatching the output of each unit.However,the rapid development of the energy Internet further enhances the uncertainty of the source and load of the microgrid: the renewable energy with a high penetration ratio on the energy supply side inevitably has volatility,which makes the microgrid scheduling face a more complex environment.The random access of electric vehicles at load side and the randomness enhancement of users’ energy demand bring challenges to microgrid scheduling.Based on this,this paper analyzes and models the unordered access of electric vehicles and the uncertainty of renewable energy output respectively for the optimal scheduling problem of microgrid,and refined the scheduling time scale continuously,so as to achieve the economy and robustness of microgrid scheduling.The main contents are as follows:(1)Aiming at the influence of unordered access of electric vehicles on the stable operation of the microgrid,a day-ahead optimal scheduling model of the microgrid was constructed considering the uncertainty of access of electric vehicles on the load side.Monte Carlo sampling method is used to model the driving distance,starting and ending charging time of electric vehicles,and obtain the disorderly charging load of electric vehicles.Then,electric vehicles are used as flexible loads that can be charged and discharged to participate in the microgrid scheduling.The improved particle swarm optimization algorithm is used to develop the dayahead optimal scheduling scheme of the microgrid.The results show that the model can effectively reduce the influence of unordered access of electric vehicles on the stable operation of the microgrid,avoid the phenomenon of "peak on peak" of the microgrid load,and improve the economy and security of the microgrid scheduling scheme.(2)Aiming at the influence of uncertainty on both sides of the source and load on the microgrid,a two-stage distributionally robust scheduling model is constructed to carry out dayahead optimization scheduling for the microgrid.On the basis of considering the unordered access uncertainty of electric vehicles,further considering the uncertainty of renewable energy output,a two-stage distributionally robust scheduling model of electric,thermal and gas coupling microgrid is constructed.At the same time,flexible electrical/thermal loads are considered on the load side to improve the economic benefits of the microgrid.In the first stage of the model,a pre-scheduling scheme was developed with the goal of minimizing the comprehensive cost of the microgrid.In the second stage,a rescheduling scheme was developed with the goal of minimizing the adjustment cost of each device,and the confidence set of the probability distribution of landscape load uncertainty is constrained based on the historical data of wind-pv-load.The results show that the model can improve the one-sidedness of stochastic optimization and robust optimization,and realize the balance between robustness and economy of scheduling schemes.(3)Aiming at the uncertainty problem of unplanned instantaneous power fluctuation of source load at different time scales,the distributed model predictive control method is used to construct the multi-time scale optimal scheduling model of microgrid.On the basis of dayahead scheduling plan,in order to satisfy the requirement of online deviation adjustment of microgrid and stabilize the interactive power of the contact line between microgrid and external network,a multi-time scale optimization scheduling strategy including day-ahead scheduling,intra-day scheduling and real-time adjustment is proposed.At the same time,the distributed model predictive control is used to realize real-time optimization scheduling,aiming at the disadvantages of large computation and high computation dimension of the centralized model predictive control.The results show that the model can adjust the microgrid in real time on the basis of the tracking day-ahead scheduling plan,reduce the influence of power fluctuation caused by the uncertainty of the source load on the microgrid,ensure the stability of the power of the contact line,and realize the robust and economic operation of the microgrid.