雜散電流監測方法比較

Comparison of Stray Current Monitoring Systems

由捷運系統產生的雜散電流對地下金屬結構物有相當程度之負面影響，其監測方法有地表電位梯度監測與結構物的對地電位量測兩種。地表電位梯度監測又分為雙電極法與多電極法，而結構物的對地電位量測則是使用銅/硫酸銅參考電極與電位記錄器來擷取資料。本文討論監測方法之應用比較，結果顯示：地表電位梯度監測之多電極法可以正確且定性地判斷地表雜散電流方向；而結構物的對地電位變化監測則可以直接瞭解結構物是否有受雜散電流腐蝕之影響。

Stray current has been recognized as a serious problem for underground structures when rail mass transit systems operating. To monitor stray current, measuring systems such as earth surface potential gradient and structure-to-earth potential have been applied. The dual-electrode method and the multi-electrode technique were performed for earth surface potential gradient measurements. Underground structure-to-soil potential monitoring was conducted by using a Cu/CuSO4 reference electrode associated with a computerized data logger to collect data. This paper presents a comparison of these two methods applied in Taipei mass rail transit systems. The results indicated that potential gradient measurements conducted by multi-electrode technique can qualitatively detect the moving direction of stray current in case of stray current occurred. For structure-to-earth potential measurements, it will give possible corrosion areas of structures due to stray current.