Lissajous Parameters based Islanding Detection of Multiple DGs in Microgrid

Unintentional Islanding Detection (UID) of Distributed Generators (DGs) in a microgrid through passive approaches is still an active area of the research as most of the existing passive approaches fail to detect UI in Non-Detection Zone (NDZ). Hence, this paper proposes a new passive technique for quick UID of multiple DGs, even in the case of zero power mismatch/ power balance, by the use of the Lissajous pattern. Point of Common Coupling (PCC) voltage and current phasors are estimated by Moving Window Discrete Fourier Transform (MWDFT). The Lissajous pattern and the associated parameters, such as slant angle, major and minor axes, are evaluated from these phasors. Based on these parameters, UI is detected. The proposed approach is tested as per the IEEE 1547 standard for different load quality factors in Real-Time Digital Simulator (RTDS). The obtained results prove the efficacy of the proposed Lissajous pattern-based UID, with detection time being less than 3 cycles for all simulated cases.