A novel criterion applicable to transformer differential protection based on waveform sinusoidal similarity identification

The Hausdorff distance (HD) algorithm has superiorities in the recognition of waveform similarity. On this basis, a novel criterion based on the HD algorithm applicable to transformer differential protection is put forward in this paper. The proposed criterion firstly normalizes the differential current sequence and synchronously creates a standard sine wave sequence. Then the HD between the two sequences is calculated to reflect the waveform sinusoidal similarity of the differential current. The proposed criterion can be used to distinguish internal faults, magnetizing inrushes and faults accompanied by CT saturation of the transformer. Simulation and experiment tests are conducted to evaluate the performance of the proposed criterion.