Analysis of very fast transients in transformers

Very fast transient overvoltages generated in gas-insulated switchgear could cause a voltage oscillation inside the connected transformer. A practical method to calculate the high-frequency transients in the transformer winding 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 frequencies up to several megahertz is checked in a model transformer and an actual 500 kV transformer. The calculated interturn voltage waveforms are in particularly good agreement with experiment.