Abstract: Abstract:In order to find the value and phase of a side current of a transformer under condition of shortcircuit fault in opposite side, the method of symmetric components is used usually. But the operation of the method is more complicated. In order to understand the graph of fault recorder of the asymmetric shortcircuit fault of the transformer in shorter time and to judge out the fault nature of the transformer and the action of the protection device in the shortest time after fault, a fast transition and calculation method of the currents of two sides of the transformer was given.

Key words: Keywords:transformer;shortcircuit current;singlephase grounding, twophase shortcircuit, analysis method