The Effects of Harmonic Components on Transformer Losses of Sinusoidal Source Supplying Non-Linear Loads

Abstract

An important consideration when evaluating the impact of harmonics is their effect on power system component and loads. Transformers are major components in power systems. The increased losses due to harmonic distortion can cause excessive losses and hence abnormal temperature rise. The measurement of iron losses and copper losses of single-phase transformers is important in particular for transformers feeding nonlinear loads. In computing of transformer losses, it is assumed that source voltage is sinusoidal and load impedance is linear. This study presents the effects of harmonic distortion of load current and voltage on single-phase transformer losses utilizing the on-line measurements (monitoring) method of the primary side. The transformer is loaded with an SCR speed controller that consists of a single-phase full-bridge rectifier, SCR and a resistant load to generate various total harmonic current and voltage distortions (THDi and THDv) conditions.