Proposal of Earthing Resistance Measurement Method without Auxiliary Electrodes

Abstract

This paper proposes an earthing resistance measurement method for a simple earthing electrode without two axially electrodes. The proposed method can measure the earthing resistance by evaluating loop impedance of an earth return circuit composed by an earth electrode of under the test and a lead wire, a return wire, the earth soil. The return wire is only put 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 resonate frequency designed 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%-+22% for earthing resistance values with 50Ω, 100Ω, 300Ω. It is found that the proposed method can be applicable to evaluate an earthing resistance around 100Ω for a simple earthing electrode.