高土壤电阻率下地铁杂散电流干扰阴保准则浅谈

Discussion on Protection Criterion for Stray Current Interference From Direct Current Traction Systems Under High Soil Resistivity

直流供电牵引的城市地铁对埋地钢质管道存在动态直流杂散电流干扰,造成管道通断电电位正负向波动严重[1],国标GB 50991[2]中管道断电电位临界准则评价动态直流干扰下管道阴保有效性实践方面存在困难;高土壤电阻率环境下,推荐标准AS2832.1[3]通过统计一个干扰周期内管道断电电位时间占比评估管道阴保有效性较为苛刻。本文通过测试某埋地钢质输油管道敷设环境的土壤电阻率,杂散电流干扰管段整改前、整改后、复测三个时间节点的24h通断电电位以及腐蚀速率,对高土壤电阻率环境下地铁动态直流干扰评价准则进行探讨。

The structure-to-soil potential have a dynamic excursion effected by DC transit systems.It is difficult to evaluate the effectiveness of pipeline cathodic protection under dynamic DC stray interference by the critical criterion of off potential in national standard GB50991.It is too strict to evaluate the effectiveness of cathodic protection by recording the potential during a sufficient period and statistic time in proportion that the potential is more positive than the protection criterion in AS2832.1.In this paper,it is to discuss the protection criterion of the structure under high soil resistivity for dc traction stray current interference by analyzing the soil resistivity,corrosion rate and the longtime potential of the different period time.