埋地长输管道交流腐蚀现场状态及其风险评估

超高压输电线路对埋地管道的交流干扰问题日益突出,国内对其交流腐蚀缺乏风险评估.以裸露X65钢模拟埋地长输管道防腐蚀涂层缺陷,采用交、直流电流及电位的在线监测和腐蚀失重等方法,研究了高压输电线路交流干扰特征及其对管道阴极保护系统的影响规律.结果表明,当土壤介质条件基本不变时,电位与电流的变化存在相似性;适当调节阴极保护电...

Field Monitoring and Risk Assessment of Alternating Current Corrosion of Buried Pipelines

The alternating current(AC) interference features of high-voltage transmission lines and their effect on the cathodic protective system of buried pipelines were investigated.Thus X65 steel coupons were used to simulate buried pipelines with coating defects.The AC and direct current(DC) as well as potential of samples were online monitored,and their corrosion-induced weight loss was measured.Results show that there are similarities between the current variation and potential variation when the soil conditions are kept roughly unchanged.AC corrosion could be effectively inhibited by properly adjusting cathodic protection current.Besides,it was inappropriate to evaluate the AC corrosion risk using either AC voltage alone or AC current density alone as the key parameter.It was recommended that joint-type criterion involving both AC density and DC density should be adopted for such a risk assessment.