地铁杂散电流对成品油管道牺牲阳极的影响及防护措施

Influence of Subway Stray Current on Sacrificial Anode of Product Oil Pipeline and Protection Measures

通过测量在地铁杂散电流干扰下牺牲阳极接入极性排流器前后的阳极排流电流、管地通断电电位和排流器两端电压等参数,系统地研究了极性排流器在管道与牺牲阳极回路中的作用及其对牺牲阳极排流效果的影响。研究结果表明:极性排流器能够有效地抑制从牺牲阳极引入管道的负向电流,也会在牺牲阳极和管道之间造成0.3 V左右的电压降,使牺牲阳极流向大地的正向电流减小。当管道安装极性排流器之后,一方面,能降低从牺牲阳极引入的杂散电流,造成部分管段牺牲阳极排流效果变好;另一方面,也能降低牺牲阳极的部分排流效果,造成部分管段牺牲阳极排流效果变差。

By measuring the discharge current,on-off potential between the pipe and the ground,as well as the voltage at both ends of electric drainage before and after sacrificial anode connected into polarized electric drainage under the interference of subway stray current,the function of polarized electric drainage in the pipeline-sacrificial anode circuit and its influence on the current drainage effect of sacrificial anode were systematically studied.The results showed that the negative current flowed from the sacrificial anode into the pipeline could be effectively suppressed by the polarized electric drainage;while the voltage between the sacrificial anode and the pipeline dropped about 0.3 V,which decreased the amount of positive current flowing from the sacrificial anode to the earth.After the installation of polarized electric drainage,on the one hand,the stray current introduced from the sacrificial anode might be dropped,resulting in better drainage effect of sacrificial anode in some pipe sections;on the other hand,drainage effect of sacrificial anode might be reduced,leading to the same or worse drainage effect of sacrificial anode in some pipe sections.