Measurements of touch and step voltages adopting multi current auxiliary electrodes

Abstract

With urban development and buildings growth adjacent to power systems, to choose suitable locations for auxiliary electrodes becomes increasingly difficult for testing the resistance, the touch and step voltages E/sub t/ and E/sub s/ in a grounding system. Accuracy of tests requires reaching remote earth and for large grounds the spacing required may not be practical or even possible. Since the rigorous measure can result in too much labor or too much expense, a simplified conservative testing method of the behavior of ground electrodes can be favorable. The measure of touch and step voltages (E/sub t/, E/sub s/) allows verifying the efficiency of grounding systems. Opposite to the measure of ground resistance GR, the measure of E/sub t/ and E/sub s/ can be done with an auxiliary electrode at a reduced distance, since it is possible to do that the error e% is positive and so the result is conservative. Furthermore adopting three or more current auxiliary electrodes, placed around the testing ground electrode symmetrically in homogeneous soil and with a special measure procedure in nonhomogeneous soil, it is possible to achieve the important goals of: an error always conservative and with a more reduced value; and lower potential values near the current electrodes themselves with more safety for operators.