Evaluation of Overvoltages Transmitted in High Power Transformer Windings at Lightning During the Design Stage

This paper presents a calculation method for voltage transmitted between the windings of the transformer while it is being subjected to the lightning impulse; it describes the reasoning and analytical relations for the predetermination of the transmitted voltage. The modeling of the phenomenon of transmitting voltage between the transformer windings was realized by using MATLAB, in order to make the calculation more efficient and to illustrate the corresponding waveforms of the transmitted voltage determined by calculation. The study was conducted on a 54/73 MVA, TTUS-ONAN, 110/15/6.6 kV transformer, and the results achieved by calculation have been validated through experimental tests.