Abstract: A method for detecting and preventing islanding includes issuing a command to an inverter connected to a power source, where the inverter is coupled to a power grid and supplies power to the power grid, the command causes a frequency of a waveform output by the inverter to vary, and the frequency of the waveform output by the inverter is a command frequency, determining that a amount of change of the command frequency is a constant value for a predetermined amount of time, removing the power supplied by the inverter from the power grid, and determining whether the power grid is valid.

Abstract: Various examples are directed to systems and methods for detecting an islanding condition at an inverter configured to couple a distributed generation system to an electrical grid network. A controller may determine a command frequency and a command frequency variation. The controller may determine that the command frequency variation indicates a potential islanding condition and send to the inverter an instruction to disconnect the distributed generation system from the electrical grid network. When the distributed generation system is disconnected from the electrical grid network, the controller may determine whether the grid network is valid.