Electromagnetic Influence Caused by Lightning Strikes on Transmission Lines to Adjacent Pipelines

A Lightning current generated when towering transmission lines are struck by lightning will flow to oil and gas steel pipelines or generate high induced voltage due to electromagnetic coupling effect, resulting in hazards such as electric shocks to workers, damage to anti-corrosion coatings or ablation of pipes. The evaluation standards and method applicability of lightning current influence on pipelines were sorted out, and numerical simulation and theoretical analysis methods were used to sort out the pipeline risk assessment methods under lightning disturbance from three aspects of personnel safety, coating integrity, and pipe integrity. The qualitative and quantitative assessment criteria for pipeline risks under lightning strike interference were obtained. The interference assessment was carried out by numerical simulation in a case based on the risk assessment criteria. The results showed that when the pipeline 8.47 m from tower grounding was struck by lightning in 100 kA current in soil resistivity of 50 Ω·m, personal safety could be guaranteed and the anti-corrosion coating had low damage risk. According to the qualitative risk assessment criteria, the distance of 8.47 m did not meet the safety distance of Mouse's ionization distance but met the safety distance specified by the Canadian electric power association (CEA), so the risk of pipeline damage was small. According to the quantitative risk assessment criteria, the maximum melted depth of the pipeline is 0.14 mm (about 0.88% of pipe wall thickness), which met the strength requirements of pipeline safe operation.