Architecture of Microgrids with Multiple Connection Points to Grids and/or Other Microgrids

Nowadays based on new improvement in smartgrid initiative and grid electricity networks, microgrids (MGs) connected to grids are more flexible, accessible, reliable, and economic. In order to attain these aims, research on various architectures of MG systems is very important. MG can be either connected to the grids or can work in islanding mode. Installing MGs in some areas improve reliability and one solution for sensitive MGs with high priority consumers such as hospitals and airports requiring more reliable and stable electricity are to provide more connections points to the grids. This paper presents a new architecture of MGs which are more complicated than other MGs. MGs considered here consist of some sub-MGs with multiple connection points to grids and/or other MGs. Architecture and matrix formulation of these kinds of MGs are defined and a number of basic facts relating to network observability, unobservable states, unobservable branches, observable islands, relevancy of measurements and algebraic-graph method for identification of islanding in power system grids would be derived in other papers based on this study. Matrix formulation which is defined is used for state estimation matrix of MG for identification of islanding and making sub-MGs inside the MG.