A new family of active antiislanding schemes based on DQ implementation for grid-connected inverters

Unintentional islanding protection of distributed generation is a key function for standards compliance. For those distributed generations that use an inverter as grid interface, the function can be implemented as part of the inverter control. Existing antiislanding schemes used in inverters have power quality and nondetection zone issues. This paper proposes a new family of schemes that have negligible power quality degradation and no nondetection zone. Design guidelines based on frequency-domain analysis is also provided. Finally, both simulation and experimental results validate the proposed schemes.