A single wire distribution network consists of a single insulated wire. Earth is used as a return conductor.
Plane problem of AC magnetic.
Power line current I = 10 A
Power frequency f = 50 Hz
Line length L = 10 km.
Electric conductivity of soil = 0.001 S/m
Electric conductivity of rock = 0.0001 S/m.
Current flows through a single-wire power line. Determine the distribution of the reverse current density in the ground.
The distribution of current density in the soil layer and in the rock and the total voltage drops.
Wikipedia: Single-wire earth return