An advanced frequency drift method for islanding detection of an inverter interfaced grid connected distributed generation

The frequency relays are unable to detect islanding of a distributed generation when the active power mismatch is below 11%, at the event the islanding has occurred. The proposed technique has been implemented for islanding detection of an inverter interfaced grid connected distributed generation for such a worst case. The scheme incorporates reactive current injection scheme to the existing frequency relay protection, which helps in suspecting islanding during the worst case, which is further reconfirmed with the help of a load shedding scheme to avoid the possibility of false detection. Computer simulation is done with MATLAB.