Research on impulse impedance measurement for grounding device of transmission tower

For obtaining impulse impedance characteristics for grounding device of UHV 1000 kV transmission tower, a portable instrument is used as the incident wave source to the grounding device, which stably outputs a 8/20 μs standard lightning current with simultaneous measurement of the response transient voltage. Tests and date recording were done to some standard resistances with nominal values, and a typical tower of UHV 1000 kV An-Tong line in Shanghai Power Grid. Transient grounding resistance in time and frequency domain (TGRT and TGRF) are analyzed and compared abased on the measured current and voltage waveforms.