Analysis of possibility of shorted coil localization in power transformer on the basis of its frequency response (SFRA)

Abstract

The article presents the results of transformer investigation using SFRA method. The 630 kVA unit with the Dyn5 connection system were investigated. The characteristics of the frequency response for the transformer without defect and with the shorted turns implemented defect were presented and analyzed. The shorted turns was performed in various parts of the HV transformer’s winding in order to check the possibility of localization of this defect. The measurements were carried out in four different ways: measurement of the frequency response of the tested winding with shorted and on free potential line terminals of the remaining windings, and inter-winding measurement − inductive and capacitive. Based on the obtained results, the influence of the shorted turns location in the transformer on its frequency response was evaluated.