A new approach based on the instantaneous power for transformer differential protection

A new method, based on the analysis of the differential instantaneous power, is put forward for the discrimination between internal fault current and inrush in transformer in this paper. This method makes use of the relation between the DC component and the fundamental component of the differential instantaneous power. It has the advantages of simple-ness and convenience that the traditional current differential protection has, and further reveals the essential difference between the internal fault current and inrush. The experiment results of HYBRISIM show that the proposed method is feasible and reliable.