Research On Micro-Grid Based On Wind And Photovoltaic Generation Systems

The portion of distributed generation systems in power system is increasing year by year due to the improved technology and the reducing cost of distributed generation. And micro-grid technology has also become a new direction of development of the power system. However, the micro-grid equipments are various, and control method as well as operation characteristics own different specialties. The large distributed power accessing to the distribution network will brought new challenges to the power system planning, the structure and operation of the electricity market structure. Therefore, studying the structure and operation characteristics of micro power grid has important significance for security and reliability of modern power system operation.Based on the Center Park load and the connected voltage, the topology structure which suitable for Lanzhou New Area is given firstly in this thesis, and the operation characteristics and the connected mode of this micro grid structure are analyzed. Combined with characteristics of different distributed power generation, operation characteristics of different distributed power generation are discussed by using the theoretical derivation and simulation model, and the model verifies that the constructed system are accurate and reasonable. This section is the foundation for building model and researching the characteristics of the micro-grid system.Then, this thesis analyzed different operation structure of micro grid and researched operation characteristics of DC micro-grid, AC micro-grid and AC-DC hybrid micro grid based on Matlab/Simulink simulation. The responses of on-grid, off-grid, switching on-grid to off-grid and the short-circuit fault of the micro-grid are researched deeply.Finally, based on joint modeling and simulation micro of grid project in Lanzhou New Area, distributed power and energy storage operating characteristics are measured and analyzed in the on-grid condition, the off-grid condition and the switching on-grid to off-grid condition. The results prove the validity of the constructed model in the thesis.