Active islanding detection for multiple parallel- connected inverter-based distributed generators using high frequency signal injection

This paper proposes a method for islanding detection in microgrids with multiple parallel-connected inverters using high frequency signal injection. In the proposed method, a master inverter injects the high frequency signal which is used by the rest of inverters for islanding detection, with two distinguishing features: 1) The slave inverters work in a high frequency current cancellation mode, what prevents interference, and 2) in case of master failure or significant changes in the grid, the remaining inverters will dynamically reassign roles, the new master inverter being self-selected, based on a deterministic performance criteria and without the need of communications.