Abstract
A combination grounding electrode of horizontal mesh and vertical conductors is, in many cases, enclosed with iron fence. When fault current flows into the grounding electrode, a person touching the fence is subjected to the touch voltage. If the touch voltage is hazardous, an additional construction work is needed for reduction of the touch voltage. For this purpose metallic rods may be vertically driven into the earth at each fence corner or at each fence center, and electrically connected to the fence.
In this paper, simulation of the touch voltages is executed by the current sources superposition method and the method of images, for homogeneous earth and two-layer earth. Touch voltages are estimated without and with driven rods. Relations between buried lengths of driven rods and touch voltages are described for various dimensions of grounding electrode, earth resistivity ratios and spacings between the grounding electrode and the fence. It is pointed out that, when the upper layer resistivity is greater than the lower layer resistivity, in some cases the maximum touch voltage arises at other positions than the fence corner.
