Surge phenomena in system of transmission line and transformer winding

This paper deals with surge phenomena in the transformer winding which are caused by switching-on processes or by the lightning stroke into the overhead line. In both cases the surge voltage or the current wave propagating via the transmission line into the transformer winding are considered and influence of the transmission lines on a travelling surge wave is studied. The model of the whole system is based on the circuits with distributed parameters and is described with the system of partial differential equations. The mathematical model is solved numerically by FDTD method it results in the time-space distribution of the voltage and the current. It enables to determine the most dangerous points at the winding and to improve a design of the isolation system and system of protections. Some illustrative examples are solved and interesting results are presented.