Investigations on sensitivity of FRA technique in diagnosis of transformer winding deformations

Abstract

This work studies the sensitivity of frequency response analysis (FRA) method in detecting different types of deformations on a 6.6 kV plain disc type transformer winding. Winding deformations such as axial displacements and inter-turn faults are experimentally simulated and the measured FRA results are presented. A high frequency transformer-winding model is developed to investigate the sensitivity of the FRA method for these winding deformations. A comparison is carried out and a good agreement is shown between measured and calculated FRA results.