Interleaved High-Voltage Transformer Windings

Interleaved-turn high-voltage transformer windings are a useful alternative to continuous disc and layer windings for a wide range of transformer output and voltage ratings. Many configurations have been devised to meet different requirements. This paper reports the discovery that the original and most- commonly-used form of interleaved winding has an unexpectedly large internal oscillatory response to chopped-wave or front-of-wave impulse (lightning surge) voltages. It describes the subsequent development of a less-oscillatory winding which allows smaller insulation clearances for equivalent reliability.