Evaluation and mitigation of underground gas pipeline coating stress due to nearby lightning stroke

Rapid economic developments have forced power networks and pipeline networks to share the same pathway. Induced voltages and currents appear on pipelines running parallel with high voltage transmission line when the transmission line is hit by lightning strike. In this study, a simulation had been carried out to determine the first lightning stroke effect on an underground pipeline coating stress. CDEGS software was used to solve Maxwell equations; in particular, HIFREQ and FFTSES tools were utilized. A 2-km underground pipeline and a 345-kV transmission line (TL) tower had been modeled. A suitable TL-pipeline distance need to determined based on lightning current, surrounding soil properties, and coating withstand voltage. In addition, horizontal and vertical rods are able to reduce the overvoltage across the coating. The first layer soil resistivity and thickness are important factors to be considered when carrying out mitigation in a non-uniform soil.