A Passive Islanding Detection Scheme for a Bipolar DC Microgrid

Islanding detection is essential for ac and dc micro-grids. Although islanding schemes for ac microgrids are widely explored, dc islanding schemes is still under development. A passive islanding detection scheme (IDS) is proposed for bipolar dc microgrids. The bipolar dc microgrid analysed is formed by an energy storage system, photovoltaic generation and dc loads. The proposed IDS monitors the total dc bus voltage and the neutral current to analyze the response of the microgrid and to distinguish genuine islanding from non-islanding events. Simulation results show that the proposed IDS differentiates islanding events from non-islanding events effectively and independently on the type of load connected to it. The IDS is tested in the presence of multiple distributed generators (DGs) and its detection time is less than 0.2 s.