ANALYSIS OF HARMONICS ON TRANSFORMER WINDINGS EDDY CURRENT LOSSES USING COMSOL MULTIPHYSICS

摘要

Modern induction furnace by virtue of rectification and high frequency inversion phenomena causes non-sinusoidal current which flows throughout the power distribution network including furnace transformer. Following the previous research work, this non-sinusoidal current contains higher order harmonics like 5th and 7th with significant magnitudes. The windings of transformers with high power rating always contain eddy current losses due to large size of conductors used, even at fundamental frequency (i.e. 50 Hz). However, in this research paper, the impact of above mentioned harmonics on eddy current losses in furnace transformer windings has been analyzed based upon practical current waveform spectrum drawn by modern induction furnace captured using latest instrumentation. For this purpose an accurate model of transformer (whose parameters are extracted from original design) has been developed in Comsol Multiphysics by using its AC/DC module. In addition, the results at fundamental frequency have also been verified experimentally.