Series-impedance of overhead transmission systems

A series-impedance evaluation of overhead transmission systems is presented. A generalization of Carson´s solution is developed by leaving aside the assumption of a filiform current distribution in overhead conductors and assuming cylindrical overhead conductors of a finite outer radius. The proximity of the earth/air plane boundary is taken into account, and a homogeneous earth with finite conductivity and quasi-steady-state conditions is assumed. The self-impedance of the earth return path and the error in Carson´s approach are evaluated. It is shown how the above error depends on the field penetration depth inside the soil, the height of the conductor above the soil, and the conductor radius