Transformer inrush
When a transformer is energised, it may draw a high magnitude transient current from the supply causing a temporary voltage dip. This current, characterised as being almost entirely unidirectional, rises abruptly to its maximum value in the first half-cycle and then decays until the normal steady-state magnetizing conditions are reached. The magnitude and duration of the inrush current depends upon the following all of which can be represented using a PSCAD model:


•the point on the voltage wave at the instant the transformer is energised (i.e. switching angle)