Analysis of very fast transients in transformers

Very fast transient overvoltages generated in gas-insulated switchgear coul d cause a voltage oscillation inside the connected transformer. A practical method to calculate the high-frequency transients in the transformer windi ng is developed based on multiconductor transmission-line theory. Resonance characteristics of a transformer are assessed using the inductance matrix obtainable from its winding geometry. Applicability to transients of freque ncies up to several megahertz is checked in a model transformer and an actu al 500kV transformer. The calculated interturn voltage waveforms are in par ticularly good agreement with experiment.