Department of Electrical Engineering,University of Tehran
This paper demonstrates a novel approach for the dierential protection of power transformers.
This method uses the Wavelet Transform (WT) and the Adaptive Network-based Fuzzy Inference
System (ANFIS) to detect a fault current from an inrush current. The proposed method has
been designed, based on the dierences between the amplitudes of wavelet transform coecients
in a special band of frequency that is caused by faults and inrush currents. The performance of
this algorithm has been simulated and tested under dierent conditions of the switching on of
power transformers, using the PSCAD/EMTDC environment software.