An Approximated Procedure to Find the Correct Measurement Point in the Fall-of-Potential Method

An approximated procedure to determine the location of the auxiliary electrodes in the fall-of-potential method, using the method of images for charged metallic spheres is presented. The classical fall-of-potential method is strictly applicable only in the case of grounding systems of small hemispheric electrodes separated by long distances, in homogeneous soil. The proposed method will allow us to consider the influence of the size and location of the current electrode in order to get the correct measuring point of the potential probe, for any distance chosen for the current electrode A grounding system consisting of complex arrangements of conductors, buried in any type of soil can be represented by an equivalent hemisphere, making it possible to obtain the correct measurement point of such system in a simple way, without the use of complex computer programs. The method has been applied to some arrangements of grounding electrodes found in published papers, and compared to them, finding very close agreement in the resultant values of the correct measurement point.