Impact of Supraharmonics on the Reliability of Distribution Transformers

Distribution transformers play a backbone role in the power grid, and it is of paramount importance to ensure high reliability of distribution transformers. Supraharmonics, an unregulated category of harmonics ranging from 2 kHz to 150 kHz, has been gaining increasing attention in recent years due to high penetration of power electronic systems in the electrical distribution network such as inverter-based resources. The presence of supraharmonics in the distribution grid poses a severe threat to the normal performance of distribution transformers, leading to higher losses and eventually higher winding temperature and reduced lifetime of the transformer. This paper focuses on the impact of supraharmonics on the reliability of distribution transformers by considering different scenarios in multi-physics modeling and simulation environment. Harmonic analyses are conducted, followed by thermal modeling, to highlight the overlooked impact of supraharmonics in diminishing the reliability of distribution transformers in the power grid.