Transformer protection by distinguishing inrush and fault current with harmonic analysis using fuzzy logic

摘要

Transformer is one of the very important components of Electrical power system. Transformers are invariably protected by using differential protection. But the differential protection sometime may malfunction due to inrush current whenever a transformer is energized. Several methods like per-phase method, cross blocking method, Percent average blocking method and Harmonic sharing method are already in existence. This paper provides an even more sophisticated and reliable method of distinguishing between fault current and magnetizing inrush by employing fuzzy logic.