Defect test of substation grounding grid based on impulse response

Abstract

Abstract The substation grounding grid has been in the open air for a long time, and it is prone to problems such as fracture and desoldering, which leads to a decrease in grounding capacity and becomes a threatening factor affecting the normal operation of the substation. Based on the principle of state response, this paper demonstrates the feasibility of using impulse current to evaluate the defects of the grounding grid, constructs an impulse impedance test system, and conducts defect detection tests on 8 m×8 m (2 m equal intervals) and 28 m×25 m (unequal interval) grounding grids in the laboratory. It analyzes the measured impulse impedance and amplitude-frequency response curves. After testing the grounding grid of a substation of a power grid company, the test results show that the test system based on the principle of state response is effective. The response voltage waveform and amplitude-frequency response curve when detecting the conductor fracture of the grounding grid are different from the waveform curve when there is no defect. It can be applied to the defect evaluation of the grounding grid and has a certain reference value for practical engineering applications.