埋地成品油管道绝缘接头漏电失效特征分析

目的 分析兰成渝成品油管道某管段绝缘接头漏电失效的原因以及对阴极保护有效性产生的影响.方法 通过电位测量、电阻测试、漏电率测试等方法对管道阴极保护系统中恒电位仪、绝缘接头绝缘性能等进行检测.对该管段进行阴极保护输出、绝缘接头两端电位等参数的返场调研检测,对绝缘接头失效部位管内腐蚀产物成分及形貌进行表征.结果 恒电位仪在...

Analysis on Current Leakage Failure of Insulation Joints of Buried Oil & Gas Pipeline

Objective To analyze the cause of the leakage failure of the insulation joint of a certain pipe section of the Lanzhou-Chengdu-Chongqing product pipeline and its impact on the effectiveness of cathodic protection. Methods The potentiostat and the insulation performance of insulating joints in the pipeline cathodic protection system were tested using potential measurement, resistance test, and leakage rate test, etc. The back-field investigation and detection of the parameters such as the cathodic protection output and the potential for both ends of the insulating joint was carried out on the pipe section, and the composition and morphology of the corrosion products of the pipe at the failure location of the insulating joint were characterized. The results show that the output voltage difference between the potentiostat before pigging and after pigging is 7.55 V, and the leakage rate of the protection side and the non-protection side is 90%. There is a large amount of pitting in the pipe sections at both ends of the insulation joint, and the depth can reach 3~3.5 mm. A large number of corrosion products are on the insulating joint gasket, mainly including Fe3O4, FeOOH and other magnetic and conductive iron oxides. Conclusion The failure of the insulation joint causes the pipeline to lose its protection. The first reason is that the outer anti-corrosion layer is damaged, and the external conductive medium will cause the pipeline to overlap; the second reason is that the magnetic conductive corrosion product inside the pipeline causes the insulation joint to be short circuited.