A new DG anti-islanding protection technique based on harmonic impedance measurement

摘要

This paper proposes a new active islanding detection scheme based on the harmonic impedance measured from distorted current and voltage waveforms. Such distortions are due to periodical short-time phase-to-phase short circuits, caused by firing a thyristor placed between two phases at the distributed generator terminals. Distributed generator islanding is identified by analyzing the change of harmonic impedance. The method was validated by simulation and experimental tests. The results show that the method is effective and robust. Moreover, it was observed that the proposed method is hardly impacted by the interaction among different signals, and its influence on power quality is negligible. Copyright © 2016 John Wiley & Sons, Ltd.