Impedance measurement for grounding grids of ultra-high-voltage Huxi substation

In this paper, taking the Shanghai area´s first impedance measurement for grounding grids of 1000kV ultra-high-voltage Huxi substation as an example, it introduces the basic situation of substation grounding grids, the test items and the method used to measure the impedance of the grounding grids. The layout of current and voltage lines and wiring in the test of substation grounding impedance are described, the impedance data are analyzed and checked which were measured with non-50Hz-frequency current method. This accumulated the engineering experience of field test and measurement technology for grounding grids of 1000kV ultra-high-voltage substation.