Hybrid passive and communications-based methods for islanding detection in medium and low voltage smart grids

Islanding condition takes place when a distributed generator (DG) continues to power a part of the grid even if power from electric utility is no longer present. Adverse effects of islanding are power quality deterioration, grid-protection interference, equipment damage, and personnel safety hazards. For these reasons, DG systems must detect an islanding condition and immediately disconnect from the grid (anti-islanding protection). This paper proposes an hybrid solution, for both low voltage (LV) and medium voltage (MV) applications, which makes use of passive and communication-based methods for islanding detection. Among the existing communication technologies, the study is focused on power line communications (PLCs). An interface device for DGs is presented, which implements the proposed method. An analysis of the proposed solution is carried out and its feasibility is showed, by means of simulation and experimental results.