International Journal of Engineering and Technology

‘Islanding’ is a term, which refers to the situation when the Distributed generator (DG) continues to power the consumer-end even when the electrical power from the electric utility is no longer present. Islanding phenomenon occurs after the certain part of the utility grid gets disconnected from a large number of inter-connected PVs. It leads to troubles in voltage and frequency control and power quality issues. Therefore there is a need for appropriate anti-islanding measures for grid-connected PV systems. There are two ways to defeat the islanding phenomenon, by reactor insertion method on utility side and capacitor insertion method on PV side. Some of the Islanding detection methods (IDMs) are broadly classifies as Active, Passive and Utility based. Active mode of detection includes impedance measurement, slip mode frequency shift and frequency bias. Passive methods contain over/under voltage and frequency and harmonics detection. Utility-based methods consist of manual disconnection, SCADA, impedance insertion.