Investigations of electrical interference of vertical earth rod arrangements

For the reliable and safe operation of electrical installations, the dissipation of natural and human-made electrical currents into the earth is of great importance. In order to safely dissipate such currents into the earth in a well-controlled manner, blank electrical conductors are specifically inserted into the earth and galvanically connected to the electrical installation. The construct of earth-sensitive conductors (earth electrodes) forms the earthing arrangement. Due to the present conductivity of the earth, galvanically separated earth electrodes interfere electrically through mutual transiting currents. This paper shows geometric arrangements of earth electrodes inserted vertically into the earth, including the effects of the electrical interference on the currents dissipated into the earth, (partial) fault voltages, as well as the resistance to earth by means of calculations. The soil layering and the varying electrical conductivity of the layers are also taken into account. In order to verify the calculations, measurements of the resistances to earth of the vertical earth rods were carried out in a substation in construction.