A passive islanding detection technique in a converter based renewable system with unbalanced load

The integration of renewable energy sources in the distribution system makes the distribution system an active one, where power flow is bidirectional. In the event of disconnection of main grid, either due to some abnormal condition or some necessary maintenance work, the renewable sources will continue to energize the local system. Due to which life of maintenance personnel will be at risk and out of phase reclosure will lead to damage of the equipments. So such formation of islands should be detected as early as possible. Here, a passive method is used for islanding detection using the voltage unbalance factor of point of common coupling (PCC) voltage. The resiliency of the method is checked for capacitor switching event as well as for load switching.