Wave Propagation on an Overhead Multiconductor in a High-Frequency Region

Carson´s, Pollaczek´s, Wise´s, and Sunde´s earth-return impedances of an overhead line have been examined, and errors involved in the formulas are explained. Modified Pollaczek´s and Carson´s/Sunde´s formulas are described. Wave propagation characteristics on a multiconductor in a high-frequency region are evaluated by adopting the modified earth-return impedance and Wise´s earth-return admittance. Sommerfeld-Goubau propagation in a high-frequency region, which shows transition between transverse electromagnetic and transverse magnetic propagation, has been confirmed in the calculated results which agree with those predicted by Kikuchi for a single conductor. On a multiconductor system, it is found that the aerial mode also shows Sommerfeld-Goubau propagation when the separation between conductors is large and the earth resistivity is high.