ABSTRACT
This chapter analyses estimation of remaining stray losses, which predominantly consist of stray losses in structural components. It discusses various countermeasures for the reduction of these stray losses and elimination of hot spots. The stray loss problem becomes increasingly important with growing transformer ratings. In the case of large generator transformers and furnace transformers, stray loss due to high current-carrying leads can become excessive, causing hot spots. Stray losses in structural components may form a large part of the total load loss if not evaluated and controlled properly. As ratings of transformers increase, the proportion of stray losses in their load loss may increase significantly. These losses in structural components may exceed the stray losses in windings in large power transformers. For large power transformers the tested load loss value at a lower current value when extrapolated to the rated condition in the square proportion may result in a value less than the actual one.
