A comparison of exact and quasi-static methods for evaluating grounding systems at high frequencies

Recently, it has been suggested that traditional quasi-static methods for evaluating power network grounding systems are not valid at high frequencies. However, the conditions under which exact full wave theory must be used have not been established. In this paper, exact full wave and quasi-static methods are used to evaluate touch and step potentials of a simple ground stake. It is shown that a sufficient condition for quasi-static theory to be valid is if the size of the buried electrode is less than one-tenth of a wavelength in the earth.