A Microgrid Islanding Performance Study Considering Time Delay in Island Detection

Microgrids (MGs) are capable of operating in grid-connected or island modes, in addition to handling the transitions between these two modes. The most difficult transition the MG can handle is the unintentional islanding. One of the problems existing in the unintentional MG islanding comes from the need to switch between inverters' control modes. The other one is that MG may operate islanded with loads external to the MG in a period of time. In order to show this problem, two simulations are performed in this paper. The first one shows that the time delay to switch inverters' control modes could lead to MG shutdown. The second one, using just one inverter control mode with no need to switch modes, shows better results with more proper conditions to maintain the operation continuity of the MG.