Estimation of Temperature Rise in MVA Range Dry - Type Transformers and Practical Verification Based on Simulated Loading

Dry-type transformer becomes the preferable choice in many applications due to its construction specific advantages over oil-cooled transformers. However, the inherent low thermal conductivity of dry-type transformers gives the rise to high operating temperatures. The temperature rise of a transformer is an important factor deciding its safe operation and the useful life span. With the increase of the power rating of the transformers the amount of heat generated during its operation increases. Thus the construction of large dry-type transformers requires a detailed understanding of their thermal behavior. In this paper the development of a 1.2MVA single phase dry-type transformer is discussed. The constructed product was tested for a 1.2MVA loading condition base on simulated loading method. Further a comparison of measured vales against the theoretically predicted values is made.