New islanding detection method with voltage amplitude variation for inverter-based distributed generator

In this paper, a new islanding detection method for inverter-based distributed generator (DG) is proposed, which is based on voltage amplitude variation. The proposed method can detect islanding with zero non-detection zone (NDZ), negligible consequence on power quality and simple performance. A new formula is embedded in the active power reference equation to deviate and accelerate the point of common coupling (PCC) voltage when islanding occurs. Therefore, a passive under/over voltage relay will be sufficient to detect islanding within the voltage permissible limit. The main benefit of the presented method is its independency from the load parameters such as loading quality factor. The proposed method is modelled with computer-aided SIMULINK/MATLAB software. The presentation of the proposed method is considered for a DG system with both unity and non-unity power factors. The performance is confirmed for different loading quality factors. Furthermore, it is also validated the proposed islanding detection method under imbalance loading.