Surge Voltage Distribution in Helical High Voltage Armature Windings

The objective of the study described in this paper was to formulate a way of calculating the distribution of surge voltage in an air-core armature winding intended for high terminal voltage use. Before such armature windings can be designed and built, the turn-to-turn insulation requirement must be determined, and that is determined in part by the surge voltage distribution. A method of calculating this distribution, based on a simplified, lumped-parameter model of the winding and using a trapezoidal rule time-step integration technique is described. The method is shown to work by comparison with a small helical air-core armature winding. Predictions are made for distributions on large armature windings.