土壤电阻率频变特性对雷击输电杆塔时埋地管道感应电压的影响

Effect of Frequency Variation of Soil Resistivity on Induced Voltage of Buried Pipelines When Lightning Strikes Transmission Tower

当雷击中输电杆塔时,在雷电流的阻性耦合和感性耦合作用下,埋地管道上的感应电压会对防腐涂层造成威胁。笔者建立了管道与输电线路平行的模型,研究了土壤电阻率频变特性对管道感应电压的影响。计算表明,土壤电阻率频变特性会使管道金属电位和防腐层电位均有所下降,由于两者下降的程度相近,导致管道防腐层两端承受的电压无明显变化,而绝缘接头的电压则有明显的降低。

When the lightning strikes the transmission tower, the induced voltage on the buried pipeline will threaten the anticorrosive coating under the resistive coupling and inductive coupling of the lightning current. A model is established in which the pipeline is parallel to the transmission line, and the influence of the frequency variation characteristics of soil resistivity on the induced voltage of the pipeline is studied. Results show that the frequency variation of soil resistivity results in a decrease on the potential of metal and anticorrosive coating of pipeline. Since the decreasing degree is almost the same, the voltage of both ends of anti-corrosion coating of pipeline has no obvious change. However, the voltage of insulated joint decreases obviously.