Measurement of Impulse Grounding Impedance in Frequency Domain

Impulse grounding impedance cannot be described as an absolute index, because it depends on the characteristic of the impulse current waveform, soil structure type and grounding system configuration, etc. This paper presents a test system to measure the impulse grounding impedance directly in time domain, moreover, calculated and defined in frequency domain. A field test for 110kV tower footing has been performed to measure the impulse ground impedance, and compared it with the ground impedance measured by fall-of-potential method.