Interference of various active islanding detection methods with positive feedback in multi-inverter power system

The islanding condition occurs when the utility is disconnected and the distributed generation (DG) continues to supply power for local load. This condition is not desirable which brings about the instability of voltage and frequency as well as the power quality degradation, thus presenting a great threaten to maintenance personnel. Considering equipment safety and personnel safety, unintentional islanding for DG operation will not be tolerated here. The study of interference of different islanding detection methods (IDMs) in multi-inverter situations as the potential method has attracted a lot of attention in relevant field. This paper discusses interaction and degradation of three active and positive feedback IDMs, including current-disturbing positive feedback, active frequency drift positive feedback, and Sandia frequency shift IDMs. Non-detection zones of multi-inverter systems in a load parameter space are used as analysis tool. Two 220 V-1kW Simulink models are set up for the simulation tests and three scenarios with potential for interference and degradation of the system are simulated. Simulation results confirm that multi-inverter equipped with both current and frequency positive feedback disturbing exhibits more complicated phenomenon than the one equipped with single disturbing method. (C) 2015 AIP Publishing LLC.