Active islanding detection method and apparatus

The present application discloses an active islanding detection method, comprising: injecting reactive current network and periodically varying disturbance to the inverter, wherein the reactive current periodically varying disturbance to the inverter and outlets voltage frequency as the moderator; amount of voltage change during the calculation of the frequency of the disturbance caused by the inverter and the network, when the amount of change satisfies a predetermined condition, determining islanding occurs, enabling timely when the grid fault islanding is detected. The present application also discloses an active islanding detection means.