地下管線受高壓交流電干擾檢測及改善

The Inspecting and elimination of Interference on Pipeline Induced by Overhead HVAC Transmission Line

邱德俊(Der-Jiunn Chiou) ； 劉定忠(Ting-Chung Liu) ； 范嘉榮(JIA-RONG FAN) ； 廖權能(Chyuan-Neng Liao)

《石油季刊》 58卷4期 (2022/12) Pp. 71-98

摘要

地下管線與高壓交流電系統共用路徑，將可能會使管線因交流電所產生的電磁效應產生干擾，此種感應效應威脅地下管線的安全，造成干擾腐蝕的風險。管線因高壓交流電系統產生的腐蝕，以誘發管線產生感應耦合傷害較為長期而明顯。高壓電力線會在其周圍產生電磁場，因交流特性而形成電磁場擴張及收縮的情況，管線切割電磁場時，形成二次變壓的電壓差，此現象為感應耦合（電磁耦合），管線帶有軸向電壓差，出現管線感應電流的流動，達到一定的程度時將使管線包覆破裂及地下管線腐蝕。干擾腐蝕電流一旦產生，鋼管包覆破損的界面及鋼管本身都成為其路徑，此路徑在環境及結構不改變下，干擾的電流將持續，終至腐蝕穿孔洩漏事件發生。雖然干擾腐蝕的速率取決多項變數，但因干擾腐蝕反應的積極性，因此腐蝕範圍小且速率快速，國內曾發生因高壓交流干擾電流使管線在數年內產生減薄53％壁厚的孔蝕事件。本研究除針對測高壓交流電是否對管線產生干擾、判斷其風險，同時嘗試進行直接排流實驗，找出引導干擾感應電流排放的規劃設計，確保管線在高壓電力線干擾下減緩或停止腐蝕的發生，確保管線輸送的安全。

關鍵字

交流電干擾 ； 腐蝕 ； 排流測試

並列摘要

Pipelines and overhead high voltage ac transmission lines share with same corridor are very common situation. In that situation, pipeline could be suffered with AC interference and cause pipeline corrosion, which is always a big issue for pipeline integrated. The inductive effect of HVAC threatens the safety of underground pipelines at all times. Pipeline with good insulation coating will showed more serious AC interference. The AC interference from the overhead high voltage ac transmission lines can be classified into three categories: capacitive, resistive and inductive. Inductive interference is the dominant interference mechanism. It should be induced voltage difference alone pipeline. AC current is generated if the voltage difference was high enough, and leave pipeline at low resistance area to make coating dis-bond and corrosion. In general, the level of AC interference depends on several factors including geometry factor like the distance between the overhead high voltage ac transmission and the length of parallelism. Coating quality on the pipeline and soil resistivity along the common corridor will also affect the AC interference. In this article, we performed difference testing for recognizing hazards induced by AC transmission line. For the pipeline showed high possibility or higher risk of AC corrosion followed CNS 15993-1 standard, we also done some trials of using different grounding to make AC current inducted on pipeline was drained. Different grounding resistances showed various levels on AC voltage on pipeline. Based on the results from several experimental, we make a design of eliminating AC interference on specific drainage location. We are also understood the AC interference should be decrease to safety level when the design applies on the highest AC location.

並列關鍵字

AC interference ； Corrosion ； Drainage testing

參考文獻

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