Abstract: Transformers are normally designed and built for use at rated frequency and perfect sinusoidal load current. A non-linear load on a transformer leads to harmonic power losses which cause to increased operational costs and additional heating in power system components. It leads to higher losses, early fatigue of insulation, premature failure and reduction of the useful life of the transformer. To prevent these problems, the rated capacity of transformer which supplies harmonic loads must be reduced. In this work a typical 100 KVA three phase distribution transformer with real practical parameters is performed under non-sinusoidal loads generated due to domestic loads. The equivalent losses and capacity of the distribution transformer is evaluated using the conventional method.
Keywords: Transformer losses; Harmonic loads; Derating.