An islanding operation of DC smart grid

Recently, smart grids are attracting attention. Already, a smart grid based on AC grid is proposed. However, due to the power fluctuation from renewable energy sources, voltage and frequency deviations are occurred in island power systems. This paper presents an islanding operation method of DC smart grid. The power system consists of photovoltaics, wind generators and controllable loads. In this paper, the DC bus voltage fluctuations of DC grid are reduced by the photovoltaics, the wind generators and the controllable loads. Therefore, the DC bus voltage is maintained within the acceptable range by applying the power control of the photovoltaics and the wind power generators and the power consumption control under the droop characteristics. As controllable loads, electric water heater and electric vehicle are assumed. Effectiveness of the proposed method is verified by numerical simulation results.