Loss of Grid

Grid connected inverters must be able to reliably detect a loss of grid condition and rapidly disconnect from the grid system.  This behavior prevents the formation of an unintentional island (a stand-alone power system with its own generation and loads operating in balance).  Current standards (e.g., IEEE 1547 and IEC 62116) specify that the inverter must disconnect within 2 seconds and remain disconnected for 5 minutes before attempting to reconnect.

In addition, there are AC voltage and frequency limits outside of which inverters must disconnect and remain off for 5 minutes.  It is not uncommon that such trips occur as a result of fluctuating power quality.  Such trips result in lost power and may need to be accounted for in PV performance model predictions, especially if the point of interconnection has power quality issues (e.g., near a large motor load).