Islanding and Single Phase Open Detection Effectiveness of a Subharmonic PLCP Based Island Detection System

This paper describes and explores the effectiveness of a novel power line carrier-based islanding detection and prevention system in which a dynamic voltage restorer (DVR) is usedto transmit a low-frequency power line carrier permissive (PLCP) signal. The approach itself is briefly described, and then results are provided showing the effectiveness of this approach in detecting unintentional islands and single-phase opens (SPOs), or series faults. The results indicate that this method works extremely well in detecting islands, with low risk of false trips, and that propagation of the signal is not expected to be a limiting factor. Fast detection (in less than 400 ms) appears possible, and the means for achieving this are described. The SPO detection results were promising, but still less than desired; SPOs were readily detected as long as there were no delta transformers or phase-phase loads on the circuits, but in reality there usually are. The paper concludes with discussion of how to improve performance, andfuture work recommendations.