Corrosion Reason of Grounding Gird at Some Towers of a 500 kV Transmission Line

In order to investigate the corrosion reason of the grounding grids of 40^#, 41^#, 42^#, and 43^# four-pole towers of a 500 kV transmission line, the analysis was conducted through ground network excavation, corrosion velocity measurement, composition analysis of resistance-reducing agents, stray current measurement, and electrochemical testing. The results showed that the resistance-reducing agent itself was highly corrosive and the non-standard construction of the grounding network and resistance-reducing agent exacerbated the corrosion of the grounding network. The resistance-reducing agent contained a relatively high concentration of Cl^-, which could easily cause localized corrosion of the grounding network. The presence of extremely strong stray currents further exacerbated the corrosion of the grounding grid.