Operation And Control Of Isolated Microgrid Including Wind Power, Storage System And Seawater Desalination Load

With many countries paying more and more attention to the protection and development of island, the exploitation of island has developed very fast in recent years. As most of the island and the surrounding have a lot of new energy, through developing the island grid and making use of new energy island reasonably, it can solve the island problems such as shortage of fuels, transportation difficulties and improve the island grid power quality. It is great significant to protect the ocean environment and improve the efficiency of new energy. Seawater desalination technology is one of the main methods to solve the problem of water shortage of island. However, the seawater desalination system has the characteristics of energy intensive. It consumes huge energy resources and results in severe environmental pollution when the introduction of seawater desalination system is numerous. The establishment of the isolated microgrid including wind power, storage system and seawater desalination load is of significant important to the normal supply of freshwater island, the use of new energy of island and the environmental protection. Therefore, establishing the isolated microgrid and studying the problem of its operation and control have significant practical meaning.Firstly, the overall structure of the isolated microgrid and each component is analyzed in this paper. The mathematical model of the isolated microgrid is built. The modeling process of the reverse osmosis desalination unit and the control strategy of seawater desalination load are analyzed emphatically.Secondly, considering the characteristic of the isolated microgrid, a coordinated control strategy based on the idea of hierarchical control is presented. The voltage and frequency of the isolated microgrid is supported by supercapacitor energy storage system with a high power density. The lithium-ion battery energy storage which has a high energy density is participated in power regulation of the isolated microgrid collaboratively. The seawater desalination load is assisted the power regulation as a controllable load at the same time. Simulation study is carried out on the platform of Matlab/Simulink to verify the feasibility of the coordinated control strategy.Finally, relying on the experimental platform of State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University), a real-time digital simulation experiment platform based on PXI is built. Lots of real-time simulation experiments are carried out to verify the correctness of the mathematical model of each microsource and load in the isolated microgrid. And real-time simulation experiments under different operation conditions are performed. The simulation results show the feasibility of the proposed coordinated control strategy.