The assessment of winding forces due to inrush current in large transformers with heavily saturated cores

It has been suspected that certain high voltage generator step-up transformers due to large inrush current occurring when the transformers were connected to the energized transmission lines but the generators were not operating. Even though the transformers are designed to withstand the winding forces developed under short circuit conditions, the transformers failed when energized. Therefore, to gain further insight into this phenomenon, this research was undertaken. The research evaluates and compares the relative magnitude of the winding forces produced under inrush and short circuit current conditions in transformers of different design and winding configurations --Abstract, page iv