A Novel Transient Saturation Detection Method for P-Class Current Transformer Using Improved Hausdorff Distance Algorithm

The P-class current transformer (CT) widely used at present creates the problem that transient saturation occurs and leads to the reduction of the reliability of the differential protection of the transformer or even false operation. This article proposes a novel CT saturation detection method to avoid differential protection false operation. First, based on the dynamic regional saturation J-A model, CT transient saturation characteristics are analyzed. These characteristics are extracted and represented using the improved Hausdorff distance algorithm, which constructs the detection scheme for CT transient saturation. The simulation tests demonstrate that the proposed scheme is feasible and rapid in various work conditions such as fault types, initial phase angle, voltage rising amplitude, and Gaussian noise signal, compared with the other saturation detection schemes. Finally, a series of fielded experiments up to 48 kA current are conducted on 330-kV protective CTs (P-class CTs). The large current dynamic experiments verify that the proposed CT saturation detection method is valid and applicable to practical engineering, which ensures that the transformer differential protection is reliable.