Infinite phase order modelling of multi-phase transmission lines

A multiphase transmission line is modelled by sinusoidally distributed charges on a cylindrical surface. In its inside, the field is uniform and outside the cylinder it can be obtained by a rotating equivalent dipole. Total charge, capacitance, required number of conductors and natural power are calculated for this idealized multiphase line model, with or without ground wires and shielding. The practical advantages of this model are presented in its application to actual multiphase transmission line geometries for the calculation of the ground level potential gradient and of maximum conductor surface gradients.