某500kV输电线路部分杆塔处接地网腐蚀的原因

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

通过接地网开挖、腐蚀速率测量、降阻剂成分分析、杂散电流测量及电化学测试等方法调查了某500kV线路40号、41号、42号和43号基杆塔处接地网的腐蚀原因。结果表明:降阻剂本身有较强的腐蚀性,接地网及降阻剂施工不规范加剧了接地网腐蚀;降阻剂中Cl^-含量较高,易造成接地网局部腐蚀;极强的杂散电流进一步加剧了接地网的腐蚀。

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 nonstandard 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.