Transformer Winding Deformation Profile using Modified Electrical Equivalent Circuit

Abstract

This study presents a generalized methodology to predict the transformer winding deformation profile through Sweep Frequency Response Analysis using Finite Element Method based Magneto Structural Analysis and proposed modified equivalent circuit. Monitoring and diagnosis of fault in any power apparatus is necessary to increase the quality life of the apparatus. In general all the power transformers are designed to withstand the mechanical forces due to short circuit faults. However, mechanical forces may exceed the specified limits during severe incidents leading to winding deformation. Winding deformation is one of the causes for the power transformer outages. In the present work, deformation profile of the winding for different short circuit currents are computed using Finite Element Method based Magneto-structural analysis. The change in circuit parameters of the deformed windings are computed using Finite Element Method based field analyses and the corresponding Sweep Frequency Responses are obtained using the modified electrical equivalent circuit. From the change in resonance frequencies, the displacement profile of the winding can be predicted which will be useful for design engineers to check the withstand capability of transformer.