Condition monitoring of power transformers through partial discharge measurement: Problems associated with pulse distortion in the windings

This paper presents various characteristics of frequency response analysis (FRA) plots from an HV auto-transformer. The aims of the paper are to draw attention to the characteristics, to stimulate discussion and to promote the need to understand and incorporate high-frequency phenomena that have been previously omitted from modelling techniques. This is critical for a full appreciation of the amplitudes and waveshape reconstructions of pd signals observed at the transformer terminals allowing more accurate pd quantification.