Effects of harmonics on temperature rise and power loss of a distribution transformer

Renewable energy-based power systems will experience a larger number of harmonics in voltages and currents due to the increased use of converters, hybrid lines, and non-linear loads in the future. These harmonics could lead to additional power and heat losses, increase operational expenses and affect the life expectancy of components. This study aims at analyzing the increased losses and temperature rise in a 25kVA oil-filled distribution transformer under well-defined harmonics. The data obtained are then used to calculate the power losses for odd and even harmonic contents and a comparison is made between the two cases. The results contribute to a better understanding of the power losses for different harmonic contents. A direct correlation between theoretical and experimental results is established, showing the negative impact of harmonics on power losses and the corresponding temperature rise in a distribution transformer.