Research On Multi-energy Coordinated Control Strategy For Island Microgrid With Renewable Energy Resources

The development and utilization of the island, as a global research focus, is drawingincreasing attention of our country, which calls for reliable power grid protection. However,traditional power transmission from mainland to the island has long transmission distances,high transmission costs and poor power supply reliability. In addition, around the island areabundant renewable energy sources. Therefore, as the microgrid technology continues tomature, the establishment of a stable and reliable microgrid in island is of great significanceto boost economic development. In order to ensure the security, stability and economicoperation of microgrid, a multi-energy coordinated control strategy is put forward againstthe problem of microgrid operation and control in this paper.Firstly, introduce the basic framework of Changdao islands power system located inShandong province along with operating principles and modeling methods of distributedpower supplies in microgrid. Based on PSACD/EMTDC simulation platform, simulationmodels of microgrid main modules are built, including wind plants, photovoltaic units,diesel power plants, load and energy storage systems.Secondly, investigate coordinated control methods of grid-connected microgridoperation, analyze PQ control mode and V/f control mode of converters, and propose thecontrol strategy of the grid-connected microgrid operation, where the main power gridprovides voltage and frequency support and makes the best use of renewable energyresources. The control strategy in two grid-connected operation modes with and withoutenergy storage is verified by simulation, and the impact of the energy storage system isanalyzed upon the grid-connected microgrid operation in island.Finally, describe isolated operation characteristics, propose the control strategies witha master-slave control, in which battery energy storage system or diesel is adopted as themaster control unit and renewable energy generation as the salve control unit. Threepotential isolated operation conditions are analyzed, corresponding coordinated controlstrategies are designed, and the feasibility of control strategies is validated by simulation.