A novel islanding detection method based on positive feedback between active current and voltage unbalance factor

摘要

Islanding detection is one of the most important functions in the photovoltaic power generation system. Conventional passive islanding detection methods suffer from the existence of non-detection zone, while active islanding detection approaches are devastating to power quality. To realize the detection of the non-detection zone and devastating, a novel islanding detection method based on positive feedback between active current and voltage unbalance factor is proposed. By detecting the voltage unbalance factor at the point of common coupling (PCC) to determine islanding and setting the determined condition of false islanding to avoid incorrect operation under false islanding situation. Theoretical analysis and simulations are conducted according to IEEE Std.1547, and the results indicate that the proposed method can detect the islanding rapidly and effectively in the worst case and avoid incorrect operation under false islanding.