| Aiming at the problems of global resource scarcity and environmental pollution,distributed power generation technology,led by wind power generation,photo-voltaic power generation and battery energy storage,has become a hot research topic for scholars all over the world,and new energy generation has become the main form of power generation in the future.In recent years,on the basis of distributed technology,micro-grid technology has been put forward,which is favored by all sectors of society because of its high energy efficiency,high supply reliability,low pollutant emission and good operation economy.The research topic of this paper is the black start of Wind/Photo-voltaic/Diesel/Storage Micro-grid,from the key problems of micro-grid black start,the establishment of micro-source model,the selection and control method of black start micro-source,the design of black start scheme and so on,the successful realization of black start is helpful to the recovery of important load in the system,accelerating the speed at which the system restores power.Firstly,the key problems in black start-up are analyzed,the mechanism of generator self-motivated magnetic and line over-voltage problems in the process is studied,and the corresponding inhibition measures are put forward,which lays a certain foundation for the success of micro-grid black start-up.Secondly,the working principle and modeling process of wind power generation system,photo-voltaic power generation system,diesel power generation system and energy storage system in micro-grid are analyzed in detail,and then the simulation models of each system are built in PSCAD/EMTDC software,which provides a certain model basis for the black start process.Then,a method of optimal power supply based on grey correlation degree is proposed,which helps the system to select the black start source quickly by comparing the size of the evaluation index function.Then,the deficiency of Droop control is analyzed,and a virtual power Droop control method based on coordinate rotation is proposed,which improves the status quo that traditional Droop control can not be directly applied to the voltage micro-grid with resistance.Finally,a micro-source voltage control method based on improved droop control characteristics is proposed,and zero-lift voltage of distribution transformer is successfully realized,and some restrictions are made on the booster time.Finally,a set of black start recovery strategy suitable for Wind/Photo-voltaic/Diesel/Storage Micro-grid is proposed,and the feasibility of the proposed recovery strategy is verified by building a micro-grid simulation model. |
