Synchronization and Reconnection of Islanded Microgrids

Microgrids can be defined as integrated systems that involve distributed energy resources and several electrical loads operating as an autonomous network, either in parallel or isolated from the main electrical network. One of the major challenges in the operation of the microgrids is the reconnecting to the grid after the islanding operation. For the reconnection of the two subsystems to occur, it is necessary that their terminal voltages are synchronized and this topic deals with a methodology which is still little explored in the literature. In this context, this work presents the implementation of an automated microgrid, in which the occurrence of islanding is detected and later the resynchronization process with the main network is performed. Through the results achieved, the efficacy of the implemented resynchronization method was shown, performing the process of reconnecting the microgrid smoothly, in accordance with the established by the IEEE-Std 1547-2003 standard.