Hierarchical Optimal Dispatching Of Active Distribution Network With Multiple Microgrids

With a large number of distributed power sources or microgrids connected to the distribution network,the traditional single power supply,one-way power flow passive distribution network becomes multi-power,two-way power flow active distribution network.Centralized single traditional dispatching mode is difficult to adapt to this change.In addition,the addition of renewable energy with randomness and volatility,such as wind and light,also has a great impact on the safe and reliable operation of active distribution network.In order to make full use of renewable energy and coordinate the optimal operation between microgrid and distribution network,it is great practical significance to study the optimal dispatching of active distribution network with multi-microgrid.In view of the decrease of reliability of active distribution system,the obvious phenomenon of discarding wind and discarding light,the continuous dispatching ability of energy storage system and the improvement of power quality of user side in active distribution network.The following studies have been carried out:Firstly,in view of the low reliability of distribution system and the obvious phenomenon of abandoning wind and light,which occurs in the operation of multi-microgrid connected distribution network.This paper proposes a new optimal scheduling model based on two-layer nested model.The inner layer aims at the minimum power fluctuation and voltage fluctuation of distribution network.Optimizing the interaction power between distribution network and interconnected microgrids can improve the safety and reliability of the system.With the goal of minimum microgrid and environmental penalty cost,and constrained by the inner scheduling result,the outer layer realizes the economical optimization scheduling of multi-microgrid,and further improves the utilization rate of renewable energy.Secondly,in order to realize the continuous scheduling ability of energy storage system,distributed energy storage device is adopted.Distributed energy storage has the advantages of independent control,plug-and-play,flexible and convenient centralized energy storage.On the basis of fully understanding its characteristics,the charge-discharge model of distributed energy storage system is established,and the dispatching strategy of distributed energy storage in multi-microgrid active distribution network is formulated according to real-time electricity price,which lays a theoretical foundation for economic scheduling before the following days.Finally,in order to improve the quality of power on the user side,an optimal scheduling model combining demand response and distributed energy storage is established in the process of optimal of active distribution network.In order to ensure the sustainable scheduling ability of distributed energy storage system,a step-by-step power correction strategy based on energy storage charge is developed.An improved firefly algorithm is used to solve the established model and apply it to the distribution system of the improved IEEE14 node.the simulation results show the effectiveness of the proposed method.