轨道交通检修基地附近燃气管道的排流试验

Drainage Test of Gas Pipeline near Rail Transit Maintenance Base

按照有关国标,对某轨道交通检修基地附近的燃气管道进行地电位梯度、通电电位、断电电位等测试,确立了管道侧的杂散电流干扰与轨交运行之间的直接关联。按照有关标准,采用强制排流方法进行了试验和测试。研究结论:当列车运行于检修基地分叉点两侧的正线线路时,电流自正线泄漏、进入燃气管道,再离开管道流回车库,经单向导通装置流回正线轨道;当列车在车库内运行时,钢轨电位升高,自距燃气管道最近处流入管道,再回流到车库。断电电位测试结果表明,管道原有的牺牲阳极可提供一定程度的保护作用。但杂散电流的剧烈干扰会加快牺牲阳极的消耗速度,增加维护困难。强制排流方法可大大减缓杂散电流的干扰作用。这种减缓既反映在通电电位的有效负偏,也反映在断电电位的改善。说明强制排流方法结合管道原有的牺牲阳极,可将管道侧的电位维持在需要的阴极保护水平。强制排流导致轨交侧的轨地电位略有升高,较之正线的轨地电位波动和车库内的轨地电位波动范围,强制排流的影响可忽略不计。若进一步改善轨交检修基地附近燃气管道的阴极保护,使其电位波动范围更窄甚至恢复到轨交停运时段的干扰水平,须根据杂散电流的实际流动回路,开发具有智能控制功能的强制排流设备。

According to the relevant national standard,the ground potential gradient,power-on potential and power-off potential of the gas pipeline near a rail transit maintenance base were tested to establish a direct correlation between the stray current interference on the pipeline side and the rail transit operation.According to the relevant standards,the forced drainage method was used to carry out the experiments and test.Research conclusion:When the train runs on the positive line on both sides of the branching point of the maintenance base,the current leaks from the positive line,enters the gas pipeline,and then leaves the pipeline and flows back to the depot,and flows back to the positive track through the single-passage device;When the train runs in the depot,the rail potential rises,the current flows into the pipeline from the nearest gas pipeline,and then flows back to the depot.The test results of the power-off potential show that the original sacrificial anode of the pipeline can provide a certain degree of protection.However,the severe interference of stray current will accelerate the consumption rate of the sacrificial anode and increase the maintenance difficulty.The forced drainage method can greatly reduce the interference effect of stray current.This slowdown is reflected both in the effective negative bias of the poweron potential and in the improvement of the power-off potential.It is shown that the forced drainage method can maintain the potential on the pipeline side at the required cathodic protection level in combination with the original sacrificial anode of the pipeline.Forced drainage causes the rail-to-ground potential on the rail side to rise slightly.Compared to the rail-to-ground potential fluctuation in the positive line and the rail-toground potential fluctuation range in the depot,the effect of forced drainage can be ignored.If the cathodic protection of the gas pipeline near the rail transit maintenance base is further improved,and the potential fluctuation range is narrower or even restored to the interference level of the rail transit shutdown period,it is necessary to develop a forced discharge device with intelligent control function according to the actual flow loop of stray current.