Research And Engineering Application Of Multimode Microgrid Operation Control And Energy Management Technology

Large number of distributed generators into the power grid will impact the power grid and users,adversely affecting the power quality,system protection and system operation.The distributed generators,loads,energy storages and control devices constitute a microgrid system as a single controllable unit,which can respond to the central control signal and coordinate the contradiction between the power grid and distributed power.Research institutions in the world have done a lot of technical research in this area and have achieved fruitful results in the operation mode,control technology and energy management of microgrids.However,based on few fixed operation modes and control methods,the means of energy management are affected by few operation modes.It is difficult to adapt to the current demands of the power grid and users on operation and energy control applications.Starting from the analysis of the structure of microgrid,the subject proposed various configurations and various operation modes of microgrid.Based on the definition of microgrid from domestic and foreign research institutes and the general characteristics of microgrids,the configuration and operation modes of microgrid are summarized.According to the distribution network voltage level and the network structure,a multi level microgrid is constructed which includes the distribution transformers regional regional low voltage microgrid,the feeder level medium voltage microgrid and the substation level high voltage microgrid.Based on four basic operation modes include the normal grid connected mode of operation,from grid to isolated network transition mode,isolated network operation mode mode this paper studies three operation status include on-grid running status,off-grid running status,fault and overhaul status of the microgrid and off network startup process,start-up process,on-grid to off-grid switching process and off the grid to into the grid switching process four switching processes.In view of the impact of grid interconnection on distribution network operation and the difficulty of uniform communication standard of microgrid in a short time,the paper studies a microgrid operation control technology based on IEC61850 three-layer control mode in order to meet the demand of future digitized power system.A control strategy is designed to adapt the operation control of the microgrid and realize the quick switching of the microgrid operation mode.The microgrid voltage control based on linear target planning is proposed to achieve the unification of microgrid control economy and reliability well.Multimode microgrid energy management framework is constructed to adapt to a variety of microgrid configuration and operation mode.The optimization scheduling method of microgrids combining the three kinds of time scale energy scheduling and the three spatial scales of station level,feeder level and substation is proposed.The influence of distributed generators intermittentity and multimode microgrid operation complexity is eliminated by using intra-day rolling energy scheduling based on hierarchical model predictive control(MPC).Design microgrid control system based on IEC61850 three-tier architecture.The microgrid control system includes a microgrid operation control subsystem and a microgrid energy management subsystem.Microgrid operation controller and microgrid communication controller are designed to control the operation of two key microgrid equipments.A modular,cross-platform,customizable micro-grid energy management system is designed.Microgrid control system has been applied in Chengde Weichang microgrid power grid project to verify a variety of microgrid operation control methods and energy management strategies,achieving the randomness and uncertainty of distributed generators into grid friendly and solving the problem of distribution network power supply,user electricity consumption and new energy utilization.The system is low cost,good compatibility,and can adapt to the large variety of access to multiple distributed power sources and the different needs of multiple types of users in the future.