Frequency-dependent Impedance of Grounding Grid using Carbon Ground Electrodes

초록

This paper presents frequency dependency of ground impedance of the carbon ground electrodes and the grounding grid combined with them. The ground impedances of the carbon ground electrode and the grounding grid were measured as a function of frequency of injection currents and simulated by using the distributed parameter circuit model with due regard to the frequency-dependence soil parameters. As a consequence, the frequency-dependent ground impedance of the carbon ground electrode and the grounding grid with carbon ground electrodes showed the capacitive behaviour at lower frequencies. It was found that the carbon ground electrode is effective in grounding system for lightning protection. The ground impedance simulated with due regard to the frequency-dependence soil parameters was in good agreement with the measured data. It is expected that the simulation method, which analyzes the frequency-dependent ground impedance of ground systems proposed in this work, could be used in design of grounding systems for protection against lightning.