Application of Park's power components to the differential protection of three-phase transformers

This paper presents a new scheme for power transformers differential protection, in which the concept of the Park's instantaneous differential powers is introduced. The proposed method is able to detect winding insulation failures and to distinguish them from magnetizing inrush current transients. Experimental and simulation results are presented and discussed.

► A new method for power transformers differential protection is proposed.
► The method is based on the analysis of the differential Park's power components.
► The method provides high sensitivity to detect incipient winding faults.
► The proposed restraining signal ensures an efficient fault/inrush discrimination.
► The restraint signal does not depend on the 2nd harmonic of the differential currents.