FDTD Simulation of Voltage Distribution in Transformer Winding under VFTO Phenomena

Power transformer is one of the most important equipments of electric power system in which a failure could cause long interruptions and costly repairs. The Very Fast Transient Overvoltage (VETO), which comprises high-order frequencies that can cause internal resonance and lead to an extremely distribution of voltage along the transformer winding. In this paper, in order to study VETO behavior in transformer winding, an improved model based on Multi-conductor Transmission Line (MTL) theory using Finite Difference-Time-Domain (FDTD) method is investigated. The accurate representation of the losses and its dependence on frequency and considering the VETO phenomenon as the traveling waves in transformer winding are the main features of the model. The simulation results show that this model can estimate the behavior of VETO phenomenon in transformer winding, so it can be used at the stage of transformer manufacturing to evaluate the strength of insulation system. Furthermore, it can be utilized to diagnose and localize various faults in transformer winding. Copyright (C) 2010 Praise Worthy Prize S.r.l. - All rights reserved.