Parameters measurement for grounding grids of a 1000kV ultra-high-voltage substation

In this paper, taking parameters measurement for grounding grids of the 1000kV ultra-high-voltage (UHV) Suzhou substation as an example, it introduces the basic situation about the designed grounding grids, the methods used to measure the power frequency (50 Hz) ground resistance (PFGR) and impulse grounding impedance (IGI), respectively. The PFGR data are analyzed and checked which were measured using the non-50Hz-frequency current method with two different instruments. While the measurement of IGI was realized using a small and portable instrument, which can output the 8/20 µs or 10/350 µs lightning currents with simultaneously recording the corresponding voltage waveforms from the grounding grids. All of work accumulated the engineering experience of the on-site test and parameters measurement technology for the grounding grids of 1000kV UHV substations.