Islanding

Islanding is the condition in which a solar or storage system keeps energizing a section of the electrical system after it has been disconnected from the utility grid.

Intentional islanding is a microgrid running on its own resources through an outage, with a grid forming inverter setting voltage and frequency. Unintentional islanding is a hazard: a distributed resource keeps a dead utility line live, so IEEE 1547 requires inverters to detect the loss of the grid and cease to energize within two seconds. A microgrid controller manages the planned transition between grid connected and island operation and the resynchronization afterward.

Also called: Island mode, Anti-islanding