Modal Analysis of Transformer Winding under Clamping Pressure Changes

This paper presents an investigative analysis on the applicability of modal analysis to identify clamping pressure changes imposed on transformer winding in terms of extracting modal parameters. Both experimental modal analysis (EMA) and operational modal analysis (OMA) were executed to observe the appearance of natural frequencies during the changes of clamping pressure. Both uniform and non-uniform clamping pressure changes were considered. Alteration of natural frequencies were observed during the laboratory experiments during every pressure change. The results obtained may contribute to online condition monitoring of transformers.