直流电车杂散电流对城市燃气管道电腐蚀的影响规律研究

为得到轨道与埋地管道并行情况下杂散电流对管道电腐蚀的影响规律,建立了基于电路原理和电力系统接地极理论的双边供电直流电车杂散电流对管地电位干扰模型,并求得了轨道电位和管地电位的分布变化函数以及杂散电流泄漏量分布函数。采用MATLAB进行了数值模拟,得到了杂散电流泄露规律及其对管地电位干扰规律,并对管道防腐蚀层单破损点、双破损点情况下管道的电腐蚀规律进行了分析。结果表明:轨道杂散电流泄露量与轨道电位大小成正比,降低轨道电阻可减小杂散电流泄露量。防腐蚀层单破损点不易产生腐蚀,双破损点导致局部腐蚀较严重,且变电站附近的点腐蚀严重。因此,应重点监测保护变电站处下方管道以减少产生多破损点的概率。

Influence of Stray Current in Direct Current Railway System on Electric Corrosion of Pipelines

In order to obtain the influence law of the stray current on the electric corrosion of the pipeline under the parallel condition of the track and the buried pipeline, the interference model of the stray current to the tube-ground potential based on the circuit principle and the grounding electrode theory of the electric power system was established. The distribution functions of the tube-ground potential/track-ground potential and the leakage of stray current were obtained. Furthermore, the numerical simulation was carried out by MATLAB to obtain the law of stray current leakage and its interference to the tube-ground potential. The corrosion law of the pipeline was analyzed under the condition of single breakage and double breakage. Results showed that the leakage of track stray current was directly proportional to the track potential, and the reduction of track resistance could reduce the leakage of stray current. The single damage point of the anticorrosive coating was not easy to cause corrosion, but the double damage points resulted in serious localized corrosion. The significant point corrosion was observed near the substation. Therefore, the protection of pipelines below the substation should be monitored seriously to reduce the probability of producing multiple breakpoints.