DefinePK

Abstract

A lightning voltage impulse is a very fast rising unidirectional transient overvoltage with magnitude of the order of several million volts and when gets in touch with the windings of a high voltage power transformer, the winding insulation will be overstressed and may get damage. This failure event incurs a heavy loss to the electric utility and is mainly responsible for transformer outages and thereby effecting the normal functioning of an electric power system. Hence a better knowledge of highly nonlinear electric stresses developed due to lightning impulses is necessary to safeguard the inner winding insulation of high voltage power transformers. In this paper, simulation analysis on a three phase wye-connected 18 coil section transformer model winding is being carried out to examine its dynamic behaviour under the influence of a standard lightning impulse and chopped impulse voltages.