Operation principle of multiple DC smart grids

Recently, smart grid has been attracting attention from the view point of the introduction of more renewable energy. However, due to the fluctuating power output of renewable energy sources, the DC bus voltage fluctuation of DC grid occurs. It becomes a major issue at the time of islanding. This paper presents coordinated operation of multiple DC smart grids. The power system consists of three DC smart grids. Each DC smart grid has PV generations, wind generators and controllable loads. In this paper, the DC bus voltage are maintained within the acceptable range by applying the power consumption control of the controllable loads, the power control by grid-connected converter and the power control by the renewable sources. Effectiveness of the proposed method is verified by simulation results in PSIMR^® environment.