Research On The Multi-time Scale Trading Method For Multi-Microgrids

Microgrid has been extensively researched in recent years,as it has the advantages of being able to effectively utilize distributed energy resources and forming an effective supplement to the main grid.This paper researches on the energy trading strategy between multi-microgrids(MMGs),with the goal of improving the economics of the MMGs and the distribution side,and proposes a trading strategy for grid-connected MMGs with multi-time scales.The main work of this paper is shown follows:First,the mathematical models of various distributed energy resources in the microgrid are established,including wind turbines,photovoltaic,micro gas turbines,diesel engines,and energy storage system.Then,a single-microgrid optimization scheduling model is established with the goal of the lowest scheduling cost.Next,the structure of the MMGs is established and a multi-time scale trading method of the grid-connected MMGs and an optimization algorithm of trading strategy based on deep learning are proposed.Firstly,an internal electricity pricing model of MMGs is established,which can dynamically adjust the internal trading price according to the changes of supply and demand situations in MMGs,and make the internal trade among the MMGs more economical than the direct trade between the MMGs and the distribution network,thus encourages each sub-microgrid to participate in internal trade.Afterwards,based on the previous work,the trading method of the MMGs with the idea of "quoting volume without quotation" is established.In day-ahead trading,each sub-microgrid finally forms a day-ahead trading plan and trading price through repeated iterations of trading power and internal trading prices,and clears day-ahead power trade;in intra-day trading,each sub-microgrid only declares an imbalance once.The power purchase and sale demand will be cleared directly after the declaration.For the intraday trading part,deep neural network algorithm training is introduced to learn the trading strategies of each sub-microgrid,so that the sub-microgrid can quickly and accurately obtain its own optimal purchase and sale plan during the intraday trading stage.In addition,based on the deviation of the expected and actual interactive power between the MMGs and the distribution network,a tie-line power deviation compensation scheme is proposed to reduce the impact of MMGs power fluctuations on the operation of the distribution network.Finally,the simulation results verify the effectiveness of the proposed model and algorithm.