埋地金属管道地铁动态直流干扰防护现场对比分析

Comparative Analysis of Dynamic Direct Current Interference Mitigation Methods for Buried Metallic Pipeline

近年来,埋地金属管道遭受的地铁动态直流干扰越来越严重,其干扰防护刻不容缓。通过现场试验对比分析了水平锌带排流、镁阳极直接排流、镁阳极极性排流以及强制电流阴极保护4种排流方式缓解地铁动态直流干扰的效果。结果表明:强制电流阴极保护的缓解效果远优于其他3种方式。当管道正向干扰范围不超过1.50V(vs CSE)时,强制电流阴极保护的有效保护范围可达十几公里,而镁阳极直接排流的有效保护范围在150 m范围内,且随着管道干扰水平的增大而降低。此外,对于牺牲阳极直接排流而言,相同干扰水平下,镁阳极直接排流效果较锌带排流效果要好。建议对于受干扰范围较大的管段,如几公里管段,应采用强制电流阴极保护的方式进行缓解,对于局部干扰管段,宜采用镁阳极直接排流的方式进行缓解。

The dramatic development of metro system deteriorates dynamic direct current （DC） interference on buried metallic pipeline in recent years. Dynamic DC interference mitigation of buried metallic pipeline is ungently in need. In this work, four mitigation methods, including zinc ribbon direct drainage, magnesium anode direct drainage, magnesium anode polarity drainage, and impressed current cathodic protection, were used for dynamic DC interference mitigation through field test and their effectiveness was evaluated and compared. Results showed that the impressed current cathodic protection method was much more effective than the other three methods. When the noble potential of interfered-pipeline was not positive than 1.50 V （vs CSE） , the effective protection length of the impressed current cathodic protection could be tens of kilometers while that of the sacrificial anode drainage methods was within 150 m. Their effective protection length decreased with increasing interference. Besides, it was found that magnesium sacrificial anode was more effective than zinc ribbon. Based on field testing results, it was suggested that the impressed current cathodic protection method should be adopted if the length of interfered-pipeline was several kilome- ters or even longer. Otherwise, the method of magnesium anode direct drainage was more applicable for the local interfered-pipeline.