Measurement of the Resistive Component of Grounding Impedance by Square Wave Excitation

The resistive component is the main component of grounding impedance, and yet there is no direct measurement method for it. Based on the square wave response of grounding systems, a direct measurement method for the resistive component of the grounding impedance is proposed. Firstly, the upper limit of the inductive component of grounding impedance has been derived theoretically. Moreover, a simplified estimation method has also been proposed with examples. Secondly, the effectiveness of square wave to measure the resistive component has been analyzed by Laplace transform. Moreover, verification in both laboratory and field has been carried out. The results show that the square wave method accurately measures the resistive component of the grounding impedance, which avoids the interference of mutual inductance during measurement. The square wave method serves as a good complement to the traditional measurement of grounding impedance.