Study frequency characteristics of ground by using four electrode method

This paper studies the effect of frequencies and penetration depth on ground impedance, resisitivity and permittivity. The effect of injected a step like current in the four electrode method for ground resistivity and permittivity measurements are investigated. The ground impedance is obtained from measured voltage and current wave forms. A balance transformer is used to inject a step current in outer electrode and sink the same current from the other outer electrode. Calculation models had been proposed to explain physically the effects of frequency and penetration depth on four electrodes method measurements.