dry-type transformer (DTT) is a type of transformer that does not use oil as a cooling and insulating medium, but instead uses solid materials such as epoxy resin, silicone rubber, or nomex paper. Dry type transformers are widely used in applications where safety, environmental protection, and low maintenance are required, such as urban areas, industrial plants, hospitals, schools, and renewable energy sources. In this article, we will discuss the advantages of dry transformers, how long they can last, and how to maintain them properly.