高压直流输电接地流对油气管道干扰及腐蚀规律数值模拟

Numerical simulation of grounding current interference and corrosion laws of high voltage direct current transmission system on oil and gas pipelines

随着长距离输电工程的发展,杂散电流引起的埋地油气管道电化学腐蚀日趋严重,其中高压直流(High Voltage Direct Current,HVDC)输电系统的接地流干扰将在管道防腐涂层缺陷处导致严重的电化学腐蚀,威胁管道运行安全。通过COMSOL软件对靠近接地极的埋地管道沿线杂散电流密度分布进行模拟分析,研究各干扰参数(管道与HVDC系统电缆夹角、接地流、土壤电导率、与接地极距离、管道半径)对管道沿线杂散电流密度分布及干扰腐蚀的影响规律。结果表明:管道与任一接地极距离小于5 km时,干扰腐蚀显著增强;管道与电缆夹角为0°时,干扰腐蚀最为严重;其余参数对管道干扰腐蚀均具有较大影响。研究结果可为管道干扰防护及维修检测提供理论依据与参考。

With the development of long-distance power transmission system,the electrochemical corrosion of buried oil and gas pipelines caused by stray current is becoming more serious.In particular,the grounding current interference of High Voltage Direct Current(HVDC)transmission system will cause serious electrochemical corrosion at the defects of pipeline anti-corrosion coating,which threatens the operation safety of pipelines.In this case,the stray current density distribution along the buried pipelines close to the grounding electrode was simulated and analyzed with the COMSOL software.Meanwhile,study was performed for the influence laws of various interference parameters(including the angle between pipeline and cable of HVDC system,the grounding current,the soil conductivity,the distance between pipeline and grounding electrode,and the pipeline radius)on stray current density distribution and interference corrosion along the pipelines.The results indicate that the interference corrosion is enhanced greatly when the distance between the pipeline and any grounding electrode was less than 5 km,and it is the most serious when the angle between the pipeline and the cable is 0°.In addition,other parameters also have great influence on the interference corrosion of pipeline.Therefore,the study results could provide theoretical basis and reference for the interference protection,maintenance and inspection of pipelines.