Research On Operation Mode And Control Method Of Multiple Microgrids In Smart Distribution System

Microgrids provide an efficient and effective approach of integrating grid interactive renewables,serving as flexible interfaces in distribution grid operation and control.Further,microgrids facilitate the paradigm shift from conventional load-centric operation of passive distribution grids to active distribution systems with multiple microgrids.Increasing deployment of microgrids urges the advances of future smart distribution networks,including diversifying controllable objectives,expanded time-spatial dismission,multiple operation targets,etc.Power flow control in the physical layer and distribution market cannot be fully satisfied in existing passive distribution grids,which requires coordinated and autonomous control to release the issues and concerns in grid standardization,microgrid privacy protection and market-competitive pricing.Therefore,coordinated control among multiple microgrids with enhanced flexibility and autonomy can be enhanced,guaranteeing safe and efficient operation.This paper focuses on the control and operation mode and optimal control strategy.An autonomous operation mode with multiple smart microgrids is developed.For multi-objective grid integration and grid service with multiple microgrids,coordinated control between microgrids and distribution grids should be clarified.Therefore,a flexible framework with multi-type microgrids should be created.First,based on the understanding of distribution grids with high percentage renewables,an approach of grid-friendly and autonomous control between smart distribution grids and multiple microgrids is proposed,to study the mechanism and characteristics of autonomous operation.Second,standardized distribution grid coordinated control and a decision mechanism with spatial directed management is proposed.Finally,a planning space with coordinated and autonomous control,including autonomous operation space,coordinated operation space and restrictions,is created to limit the operation of microgrids,lower down the dismission of microgrid operation,and enhance the flexibility and autonomy of interactive operation between multiple microgrids and distribution grids.In the framework with coordinated distribution grid operation,focusing on large power central microgrid,the intermittency of distributed energy resources is the major problem to solve to mitigate the imbalance between supply and demand.The operation model of smart distribution grids and microgrids is created as a mixed integral second-order optimization problem to minimize the smart distribution grid costs by optimally dispatching and control multiple microgrids reactive power and active power regulation.A rewarding zone among the optimal operating point will be created to incentivize multiple microgrids.The coordinated control with large power centralized microgrid can effectively enhance physical system security and ensure power quality.In the framework with coordinated distribution grid operation,focusing on small-scale dispersed microgrids with privacy protection requirements,a coordinated control with privacy insurance in distribution grids with multiple microgrids is proposed to model the information and energy exchange between distribution grids and multiple microgrids.Based on extended Benders approach,a distributed economic dispatch without violating microgrid privacy is proposed.This approach ensures the information privacy of microgrids and ensures the operation efficiency and security of distribution grids.The solving efficiency is enhanced with respecting the guarantee of obtaining an optimal solution.Therefore,the optimal dispatching and innovative business model is provided.In the framework with coordinated distribution grid operation,focusing on small-scale dispersed microgrids with privacy protection requirements,a distributed and coordinated control is created to achieve a game model between distribution grid market and node price.The low level model is the game between multiple microgrids to maximize the profits and provide the best strategy to compete in the power market.The high level model is to calculate the electricity price of distribution grids.The interactive approach is proposed to solve the game model and equivalent points,and thereby enhance the coordinated operation.The model can help benefit interaction and trading among multiple microgrids based on market profits.