Based on the microbend effect of optical fiber, a distributed sensor for real-time continuous monitoring of intrusion in application to buried pipelines is proposed. The sensing element is a long cable with a special ...Based on the microbend effect of optical fiber, a distributed sensor for real-time continuous monitoring of intrusion in application to buried pipelines is proposed. The sensing element is a long cable with a special structure made up of an elastic polymer wire, an optical fiber, and a metal wire. The damage point is located with an embedded optical time domain reflectometry （OTDR） instrument. The intrusion types can be indicated by the amplitude of output voltage. Experimental results show that the detection system can alarm adequately under abnormal load and can locate the intrusion point within 22.4 m for distance of 3.023 km.展开更多
DC stray current can cause severe corrosion on buried pipelines.In this study,firstly,we deduced the equation of DC stray current interference on pipelines.Next,the cathode boundary condition was discretized with pipe...DC stray current can cause severe corrosion on buried pipelines.In this study,firstly,we deduced the equation of DC stray current interference on pipelines.Next,the cathode boundary condition was discretized with pipe elements,and corresponding experiments were designed to validate the mathematical model.Finally,the numerical simulation program BEASY was used to study the corrosion effect of DC stray current that an auxiliary anode bed generated in an impressed current cathodic protection system.The effects of crossing angle,crossing distance,distance of the two pipelines,anode output current,depth,and soil resistivity were investigated.Our results indicate that pipeline crossing substantially affects the corrosion potential of both protected and unprotected pipelines.Pipeline crossing angles,crossing distances,and anode depths,our results suggest,have no significant influence.Decreasing anode output current or soil resistivity reduces pipeline corrosion gradually.A reduction of corrosion also occurs when the distance between two parallel pipelines increases.展开更多
基金This work was supported by the Scientific Study and Technology Development Fund of China National Petroleum Cooperation (CNPC).
文摘Based on the microbend effect of optical fiber, a distributed sensor for real-time continuous monitoring of intrusion in application to buried pipelines is proposed. The sensing element is a long cable with a special structure made up of an elastic polymer wire, an optical fiber, and a metal wire. The damage point is located with an embedded optical time domain reflectometry （OTDR） instrument. The intrusion types can be indicated by the amplitude of output voltage. Experimental results show that the detection system can alarm adequately under abnormal load and can locate the intrusion point within 22.4 m for distance of 3.023 km.
文摘DC stray current can cause severe corrosion on buried pipelines.In this study,firstly,we deduced the equation of DC stray current interference on pipelines.Next,the cathode boundary condition was discretized with pipe elements,and corresponding experiments were designed to validate the mathematical model.Finally,the numerical simulation program BEASY was used to study the corrosion effect of DC stray current that an auxiliary anode bed generated in an impressed current cathodic protection system.The effects of crossing angle,crossing distance,distance of the two pipelines,anode output current,depth,and soil resistivity were investigated.Our results indicate that pipeline crossing substantially affects the corrosion potential of both protected and unprotected pipelines.Pipeline crossing angles,crossing distances,and anode depths,our results suggest,have no significant influence.Decreasing anode output current or soil resistivity reduces pipeline corrosion gradually.A reduction of corrosion also occurs when the distance between two parallel pipelines increases.
