Transformer Engineering, 2nd Edition

6

Short-Circuit Stresses and Strength

A steady increase in demand of electrical power has resulted in the addition of more generating capacity and interconnections in power systems. Both these factors have contributed to an increase in short-circuit capacity of networks, making the short-circuit duty of transformers more severe. Failure of transformers due to short circuits is a major concern for transformer users. The success rate during short-circuit tests is far from satisfactory. The test data from high power test laboratories around the world indicates that on an average practically one out of four transformers has failed during the short-circuit test, and the failure rate is above 40% for transformers above 100 MVA rating [1]. There have ...