Evaluation of the Image Processing Technique in Interpretation of Polar Plot Characteristics of Transformer Frequency Response

Frequency response analysis (FRA) is one of the most efficient methods that can diagnose the mechanical faults of power transformers. Digital image processing of the FRA polar plot characteristics has been recently proposed in the literature for the interpretation of power transformers Frequency response. The important advantage of this method is using the phase angle of the FRA trace in addition to its amplitude for the analysis. The digital image processing techniques implemented on the FRA polar plot detect the fault by extracting and analyzing different features of the image by using texture analysis. In this study, the performance of this method is investigated on real windings to examine its ability in detecting the fault extent and type. This step is mandatory since the method is new in the FRA field and has been investigated only in simulation cases. Three different faults, including axial displacement, disk space variation, and radial deformation, are implemented in the experimental setup for the study. Results of implementation of this approach show that this approach neither can determine the fault extent nor the fault type. Therefore, essential changes need to be implemented in the method before applying it in the field.