Analysis of the grid harmonics and their impacts on distribution transformers

Widespread application of power electronics in industrial and residential loads has increased the harmonics of the grid significantly. The grid harmonics have destructive impacts on the gird components including distribution transformers. Studying the impacts of current harmonics on distribution transformers is crucial for grid design and maintenance. Therefore, this paper studies the effect of gird harmonics on eddy current loss, other stray losses, hottest spot temperature, and lifetime of distribution transformers. The current harmonics of six 100KVA transformers at a provincial power distribution center are measured in a one week test period and the impacts of grid harmonics on the investigated transformer are thoroughly discussed.