Determination of Transformer Rating Based on Total Harmonic Distortion Under Balanced Conditions

In the present article, the effects of a non-linear load under balanced conditions on the rating of a transformer are analysed. Non-linear loads are related to temperature increases in a transformer, which lead to deterioration and reduction of lifetime. Due to the unwanted effects of harmonic components in non-linear loads, the load connected to the transformer should be reduced. In other words, to supply a specific load, the rating of the transformer should be increased to sustain the rise in heat. The aforementioned methods of overcoming the effects of non-linear loads are known as de-rating. By assuming that the transformer’s rating is a linear function of the THD, a method of selecting the transformer’s rating based on the total harmonic distortion (THD) of the load was developed in the present study.