To identify power transformers, look for key features such as their size, which is typically large, and their construction, often housed in metal enclosures. Check for nameplates that provide essential information like voltage ratings, power capacity (measured in MVA), and manufacturer details. Additionally, observe the cooling methods used, such as oil or air cooling, and inspect the connections and bushings for high-voltage lines. These characteristics help distinguish power transformers from other types of transformers.