English title

In this paper, a new method has been presented for differential protection of power transformers.  In this approach, chaotic method has been used for distinguishing of inrush current from internal fault current of the transformer. The proposed algorithm has been designed based on analysis of harmonic components of the differential current of the transformer due to internal faults and inrush currents in a specific frequency band. To verify the capability of the proposed algorithm a 230/63 kV power transformer connected to the 230 kV power system has been simulated at EMTP/ATP software under various internal faults and switching situations. The obtained information has been used in MATLAB/SIMULINK In order to apply the chaotic theory for recognizing inrush current from internal fault current. Simulation results show successful operation of the proposed algorithm.