Novel anti-islanding algorithm for inverter-based distributed generation system

Aside from benefits, integration of distributed generation (DG) exposes whole power system to risk. DG is not like the traditional generation through rotating masses, it's behavior is different with the traditional generators especially under fault conditions. A condition needs to be detected when DG is supplying power to load while the main grid is disconnected. One of the vital outcomes of this work is to detect the islanding events under the weak grid and worst load conditions that will make the system more protected and reliable. In this work frequency variation, reactive power mismatch and rate of change of frequency over reactive power are used to detect islanding. A modified fuzzy logic based phase locked loop is proposed to detect islanding with the negligible non-detection zone. The mentioned scheme will be applied and tested based on IEEE-1547 standard. The results are presented and discussed in detail.