Current distribution under high frequency and transient conditions in earth electrode systems

Vertical earth rods are frequently used in conjunction with earth electrode systems such as grids or horizontal electrodes with the aim of decreasing the earth impedance at an installation. Horizontal earth electrodes may also be enhanced with additional conductors. In this paper, the current distribution in such combined earth systems is investigated. Two specific earthing arrangements are the subject of this study; (i) a 2.4m vertical rod with horizontal electrode enhancements in a `cross´ formation and (ii) an 88m horizontal electrode with a parallel insulated interconnected conductor. Experimental studies of these systems are presented and the analysis of the measured current distribution results allowed the contribution of the additional conductors to be clarified.