Research On Operation And Control Strategy Of Isolated Microgrid System

China strongly supports the development of low-carbon,green and environment-friendly electric power industry.The development and application of new energy technologies such as wind power and photovoltaic are of great significance to the development trend of the power industry in the future.For some remote areas,the investment of power transmission and distribution system is large,maintenance is difficult,and the reliability of power supply is poor.Once some small disturbance or failure occurs,it will lead to the collapse of some power grids,causing unpredictable losses.Isolated micro-grid system is an effective utilization form of wind-solar storage combined power generation system.Isolate micro-grid system can timely adopt local distributed energy source,that installation site is flexible,environment-friendly and pollution-free,and can be supply with nearby load with rich resources.Due to the obvious advantages of isolated micro grid,many scholars at home and abroad have paid close attention to and conducted research and analysis.Isolated micro-grid has become a new power supply mode with rapid development in recent years.The integrated utilization of green and environment-friendly clean and renewable energy vigorously advocated by the state is the main form of future application and development of isolated micro-grid.At present,most studies involving isolated micro-grid system are experimental verification,but theoretical analysis and research on the system are still scarce.Some problems still need to be further studied and improved.Therefore,this paper takes the operation and coordination control strategy of the isolated micro-grid system as the research focus,and conducts theoretical analysis and research of the isolated micro-grid system.The main research work is as follows:(1)The typical structure of isolated microgrid system is reviewed.The key methods of operation and control of isolated microgrid system are analyzed.The future research directions of isolated microgrid system are prospected and summarized.(2)The isolated microgrid system model of photovoltaic power generation system,wind power generation system and energy storage system was built and simulated.The control strategy of this chapter adopts master-slave control,photovoltaic power generation system and wind power system as the slave power source,adopts PQ control strategy,energy storage system as the main power source,adopts v/f control strategy.(3)Based on multi-intelligence technology,the multi-layered isolated micro-grid system is proposed to coordinate control strategies.For the power unbalanced operation condition,the control mode is converted.With the upper concentration of the upper concentration and the lower decentralized coordination,the real-time power balance of the isolated micro-grid system,the power of the emergency power control and the energy optimum at the steady state of the grid is controlled by multi-level power balance,so as to ensure the coordinated operation of the isolated micro-grid system.(4)Based on the multi-layered isolation microgrid system's coordinated control strategy,using MATLAB/Simulink software to simulate two control strategies under different loads and in different conditions.The simulation verifies the effectiveness of the coordination control strategy proposed in this paper.(5)In the microgrid laboratory and off-grid experiments,the large power grid is operated as an isolated microgrid.Through voltage simulation analysis,the stability of the isolated microgrid system is verified.The research results of this topic can provide key technical and practical basis for the research of operation and coordination control of isolated micro-grid system.