Abstract: | This paper proposes an earthing resistance measurement method for a simple earthing electrode without two auxiliary electrodes. The proposed method can measure the earthing resistance by evaluating loop impedance of an earth return circuit composed of an earth electrode of the under test and a lead wire, a return wire, and the earth soil. The return wire is placed on the soil surface without any terminations. The earthing resistance of the electrode of the under test can be given by the earth return circuit impedance at a resonant frequency design between 100 kHz and 1 MHz. The measurement conditions for the proposed method are determined by numerical calculations. Earthing resistance deviations between the proposed method and the existing method are ?13% to +22% for earthing resistance values with 50, 100, or 300Ω. It is found that the proposed method can be used to evaluate an earthing resistance around 100Ω for a simple earthing electrode. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(3): 16–26, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20196 |