雷击超高压交流输电线路对埋地输油输气管道的电磁影响

Electromagnetic Effects on Underground Oil/Gas Pipeline of the Lightning Strike on EHV AC Transmission Line

以甘肃河西750kV交流输电线路为例,深入研究和解决了超高压交流输电线路遭受雷击时对邻近输油输气管道的电磁影响问题。通过建立EMTP时域仿真计算模型,获得了雷击输电线路杆塔时避雷线电流和杆塔入地电流的分布特性以及杆塔冲击接地阻抗、雷击点位置等对避雷线电流和杆塔入地电流的影响规律。基于线矩量法计算模型,仿真研究了线路与管道平行接近时管道电位、涂层电位和防腐层电压的分布特性和衰减规律,归纳推导了线路与管道交叉跨越时管道防腐层电压的简化计算公式,该公式可以考虑雷电流幅值、管道类型、土壤电阻率以及管道至杆塔接地体距离的影响。结合3层聚乙烯(PE)防腐层的雷电冲击耐压限值,得到了不同幅值的雷电流作用下满足防腐层耐压限值要求的管道与杆塔接地体的允许接近距离,为今后电力工程和油气管道工程的建设提供了重要的参考数据。

Taking a 750kV EHV double circuit line on the same tower for example,we studied the electromagnetic influence of the lightning strike on underground oil/gas pipeline on transmission line.By modeling of EMTP,we can obtain the distribution characteristics of current along ground wire and tower and the effect of ground impedance and lightning location after lightning strikes on tower.Based on the computational model for the method of moment,the distribution characteristics of the metal potential,coating potential,and coating stress voltage on the oil/gas pipeline parallel to or across the transmission line are investigated,and the approximate expression for the cross is obtained,which involves the lightning current,pipeline type,soil resistivity,and the distance between the pipeline and tower grounding structure.With the lightning electrical strengths of different coatings,we can achieve the safety distance between the pipeline and tower grounding structure for different lightning current peaks,providing important reference data for power engineering and oil/gas pipeline construction.