A Study On Effects Of Stray Current Corrosion In Long Distance Pipeline

Long-distance oil and gas pipelines as the primary means of transported over longdistances of oil and natural gas, usually are laid underground, geographic span and complexlaying environment. Leakage and damage was difficultly discovered, and the buried pipelinerepairs require a lot of land and earthworks. It is time-consuming and laborious, and thereforeits protection and detection are received more and more attention by the pipeline enterprises.However, stray currents generated by electric railway operations increasingly become abottleneck troubled buried pipeline development, which blocked the normal operation of theburied pipelines. Research on the stray current corrosion of long-distance pipeline, timelydetection of the pipeline, problems are found and to be corrective and preventing corrosionpipeline leak are an important guarantee for the safe use of the pipe.Based on the principle of electrochemical corrosion, this paper analyzes the principle oflong-distance pipeline soil types and stray current corrosion of pipeline corrosion and metalinterference factors affecting stray current. And turn it into the interference into the electrifiedrailway, the influence of electrochemical corrosion, the cathodic protection influence of oiland gas pipelines and other causal factors. The effects on pipelines corrosion of stray currentcan be divided into the potential influence of AC and DC, the impact on the corrosion rate andthe effects on cathodic protection of AC and DC.The detection of stray current is divided into the pipe-to-soil potential measurement, soilpotential gradient and stray current direction measurement, the voltage between the rail andpipeline measurement, tube current measurement, soil resistivity measurement, track currentand leakage current measurement, pipeline AC interference voltage measurement and ACparameter measurements, which introduces its measurement methods, instruments andprocedures. The method with interference corrosion protection of stray current forlong-distance pipelines is studied, drain protection of which is the method of most commonlyused, also been the widely used method in construction pipeline. A detailed study has beendone for the protection of dc drainage and ac drainage, including its characteristics,determination of drainage flow appoint and calculation of drainage flow and evaluation and adjustment of the later. According to engineering problems, detection method is proposed forstray current interference problem of oil pipeline from Yan’an to Xi’an in Yanchang Petroleum,and made the corresponding solutions based on the test results.