FEM ANALYSIS OF POWER TRANSFORMER TO STUDY THE EFFECTS OF HARMONICS ON LOSSES

Abstract

The significance of harmonics in power systems has increased substantially due to the use of solid state controlled loads and other high frequency producing devices. An important consideration when evaluating the impact of harmonics is their effect on power system components and loads. Transformers are major components in power systems. The increased losses due to harmonic distortion can cause excessive winding loss and hence abnormal temperature rise. Existing standards give a procedure to determine the capability of an existing transformer subject to nonsinusoidal load currents based on conservative assumptions. In this work a 10 MVA transformer is taken under non-linear loads generated due to domestic loads. The equivalent losses and the capability of transformer is evaluated using the conventional method as well as from the FEM based solution method. it is the purpose of this research effort to quantify the increased winding losses due to harmonics and the corresponding temperature rise in transformers. This is accomplished using a 2-D FEM model adapted for winding loss calculation. Then a comparison is made between two methods of computations.