Research On Protection And Effect Of Stray Current Induced By Electric Railway On Buried Pipeline

With the rapid development of the national economy and the improvement of people's living standards,the energy industry,the power industry,the electrified railway transportation system and so on have been greatly developed.In general,the built of transmission lines,electrified railways and buried pipelines follow the selection principle of the row first,which appeared in the status quo that a large number of buried steely pipelines are parallel and intersecting with overhead high-tension alternating current transmission line.In such a situation,the overhead high-tension alternating current transmission lines or alternating current electrified railway lines near the buried pipeline will produce alternating disturbances and alternating corrosion of buried pipelines by the resistance coupling,capacitive coupling or electromagnetic induction coupling.Moreover,it will interfere with the operation of the buried pipeline cathodic protection system.Therefore,how to systematically protect the pipeline is an extremely important practical problem.In this case,the influence of electrified railway stray current on the corrosion degree of buried metal pipelines and the protection of stray current corrosion in electrified railway were studied through laboratory experiment and field experiment in the paper.The results of laboratory experiments show that the pipe-to-soil potential decreases with the increase of the parallel distance between the pipeline and the electrode.The maximum value of pipe-to-soil potential appears at the off electrode(the leakage point and return point).With the cross angle between the electrified railway and the buried metal pipeline increasing in the acute angle range,the pipe-to-soil potential value of each measuring point is gradually reduced.At a fixed crossing angle,the pipe-to-soil potential decreases as the distance between the pipeline measuring point and the electrode(i.e,the leakage point and return point)increases.In the field experiment,the influence of stray current in underground pipeline was parameter tested,whose results show that the stray current in the adjacent underground oil-gas pipeline increases obviously with the increase of the load current of the electrified railway;With the increase of the angle between the electrified railway and the pipeline,the influence of the high-tension line on the buried pipeline is generally reduced;With the increase of the parallel distance between the electrified railway and the pipeline,the interference influence degree of the electrified railway on the pipeline is generally reduced.On the basis of the above,the direct discharge method,the straight row discharge method and negative potential discharge method was selected,which found the use of magnesium alloy electrode at earth electrode get great effect,using discharge devices(such as diodes)for the polarity of the discharge at the same time.And its application in the two pipeline of the petrochemical station(Wang Huaxian line and from Urumqi Petrochemical to petrochemical line)severely affected by the high-tension lines stray current,And its application to the high voltage line stray current affect the two petrochemical stations(Wanghua Line and Wu Petrochemical to the petrochemical line),discharge effect is significant,12 discharge points by spurious The current effect is greatly reduced,the discharge point regardless of the tube potential fluctuations or the potential of the tube potential forward and negative are greatly reduced.