Influence of the grounding electrode conductivity on the induced transient current

The paper deals with the assessment of the influence of finite conductivity of the horizontal electrode to related transient response. Transient response of the grounding electrode buried in a lossy half-space is determined via analytical solution of the corresponding Pocklington equation in the frequency domain. Time domain response is obtained by means of Inverse Fast Fourier Transform (IFFT). The electrode is excited via an equivalent current source representing the lightning strike current. Presence of the earth-air interface is taken into account via a simplified reflection coefficient arising from the Modified Image Theory (MIT). The transient current at the center of the electrode is calculated for the case of perfectly conducting (PEC) electrode and for the electrodes made of copper and aluminum. Comparison of the results shows no discrepancy between these electrodes, justifying the use of a PEC electrode approximation.