Multi Microgrid Coordinated Optimal Scheduling For Distribution Network

In order to alleviate the energy crisis and solve the environmental deterioration,people need to carry out energy reform globally,vigorously develop new and sustainable clean energy,and make full use of the natural advantages of renewable clean energy such as wind,solar and tidal energy.Under this situation,how to increase the proportion of new energy generation in the energy structure and improve the utilization rate of new energy,how to make the long-term stable power supply of new energy generation and how to improve the efficiency of new energy generation have become the focus of scholars around the world.As a new micro-grid dispatching mode,the collaborative operation of multi-microgrid can support the operation of distribution network by connecting local distribution network through public connection points,or can form a separate multi-microgrid system to operate independently.Considering the particularity of electric vehicle load in micro-grid and the flexibility of multi-micro-grid system capacity adjustment in off-grid state,as well as the different optimization objectives of distribution network system and multi-micro-grid system,this paper studies the optimal dispatch of multi-micro-grid with the participation of new energy electric vehicle,the cooperative operation of multi-micro-grid in off-grid state,and the double-layer optimization of distribution network and multi-micro-grid.The main work and results of the scheduling model are as follows:(1)This paper establishes a collaborative optimal dispatch model for multi-microgrid system with electric vehicle.By using the influence of charging and discharging behavior of electric vehicle on the load state of micro-grid,the effect of orderly charging and discharging of electric vehicle is optimized by time-sharing electricity price,and the superiority of multiple micro-grids under combined operation mode is verified.(2)Considering the power quality of the multi-microgrid system itself,an optimal dispatch model for off-grid multi-microgrid system is proposed,which considers interruptible load and dynamic backup capacity based on wind power output prediction.The optimal dispatch is carried out with the overall economic benefit of the off-grid multi-microgrid system as the optimization target,and the validity of the model is verified by an example analysis.(3)Based on the cooperative and competitive relationship between the multi-microgrid system and the distribution network system in the actual operation,the optimization objectives of the distribution network and the microgrid are analyzed,and a two-layer optimal dispatch model is established.Using the power interaction between the distribution network and the microgrid as the connection point,the two-tier model is optimized,and the different optimization objectives of the two-tier model are coordinated to optimize the efficiency of the entire power network system.The access of the micro-grid under the dual-layer model scheduling effectively improves the power quality of the distribution network,and the distribution network plays a very good supporting role for the microgrid.