Investigation of Positive Feedback Anti-Islanding Control for Multiple Inverter-Based Distributed Generators

The positive feedback-based anti-islanding scheme has become a common anti-islanding protection technique for inverter-based distributed generators (DGs). This paper investigates the scheme´s impact on the small-signal stability of multiple inverter-based DGs installed in power distribution systems during grid-connected operation. The interactions among multiple-DGs due to the anti-islanding scheme are also addressed. An index is proposed to quantify the destabilizing effect of the aggregated positive feedback activities of multiple DGs. This paper further introduces a DG power transfer limit versus islanding detection time curve to reveal the conflicting requirements of anti-islanding protection speed and the maximum power transfer of multi-DG systems.