The Influence of Supply Voltage Phase Angle on the Transient Current Generated on Transformer Energization

This paper presents a method of predetermining the transient current generated during transformer energization, in order to adopt optimal solutions to prevent the failure situations. Due to the shock produced by this transient current in transformer windings, and, given the fact that its magnitude is dependent on the moment of the transformer energization, i.e. on the value of the phase angle of the supply voltage, for the purpose of current attenuation simulations were carried out to determine the optimum connection angle. The method was applied to a 15 MVA, 10.5 / 6.3 kV power transformer, with Δ/Δ0 connection, and the results obtained were validated by laboratory tests.