交流電在地下管線陰極防蝕引起的效應研究

Effects of Alternating Current on Cathodic Protection of Underground Pipelines

交流電（AC）引起的腐蝕從20世紀的早期就已經被很多學者討論了，但是對地下管道的交流腐蝕作用，由於近代大容量AC高電壓供電線路和輸油輸氣管線需求急速增加，直到最近十幾年來才被證明。這篇文章嘗試分辨地下管道遭AC腐蝕的可能性。透過現場各種管線測量和實驗室試驗，證明AC電流可能造成現有陰極防蝕檢測數據的誤判；同時也證明，即使達到現有的陰極防蝕標準（NACE RP0169），當管線表面發生交流電流密度大於100A/m2時，管線仍然會發生腐蝕的結論。

The phenomenon of alternating current (AC)-induced corrosion has been considered by many authors since the early 1900s, but the corrosive action of this current on the pipeline is not well known or well documented. This paper is an attempt to identify the possibility of AC corrosion for buried pipelines. By conducting various field and laboratory tests, AC currents may pose a threat to underground structures and cathodic protection (CP) requirements needed to mitigate the possible adverse AC current effects. However, even though CP criteria are matched, AC corrosion still takes place as AC currents is larger than 100 A/m2.