Anti-Islanding Scheme of PV System under Parallel Operation of PCS

Unintentional islanding detection is one of the key function for standards compliance for a grid-connected photovoltaic (PV) inverter. Some anti-islanding schemes still have non-detection zone (NDZ) issues and problems which deteriorate performance of islanding detection under parallel operation. In these regards, we analyzed the NDZ in deliberate procedure and proposed a new anti-islanding scheme that can precisely detect islanding without NDZ and islanding detection under parallel operation exactly. In addition, it has negligible power quality degradation such as total harmonic distortion increase. The proposed scheme is validated by simulations and experimental results.