Operating Modes of a Commercial and Industrial Building Microgrid with Electrical Generation and Storage

This paper describes the several operating modes of a Commercial and Industrial (C&I) building microgrid that allows for seamless transition between the grid connected and the islanded modes. The microgrid described in this paper is composed of a diesel generator, a Li-Ion battery system and electrical loads. The Li-Ion battery system is interfaced with the grid by using a power electronics converter, whilst the synchronous machine of the diesel generator is directly connected to the building electrical grid. Depending whether the diesel generator is running or not during the transition and its operating mode, the battery system will remain in grid connected mode or will adapt its control strategy to grid forming or droop operation.