Electric-field distribution around an isolated stranded Conductor

The voltage and electric field around an isolated stranded conductor is required for calculating corona-inception and break down levels. A seminumerical (semianalytical) method for calculating the voltage and field is described. The field enhancement at the tip of each strand is about 40%, higher than the field for a smooth cylindrical wire of the same overall diameter. This is true for any reasonable number of strands in the outer layer (from six to, say, 60); in particular, the enhancement is 39 4% for the stranded conductors used for 400 kV transmission with 24 outer strands. The effect of strand spiralling is shown to be negligible.