Study on the Numerical Simulation of Coupling Interference Law of AC Transmission Lines to Buried Pipelines

In energy public corridors， the similar routing of AC transmission lines and buried pipelines inevitably causes the pipeline to enter the AC interference zone， leading to pipeline AC corrosion， abnormal cathodic protection systems， and posing a threat to pipeline operation safety.To study the coupling interference law of AC transmission lines on buried pipelines， based on the pipeline equivalent circuit and electromagnetic induction theory， a model of AC interference of transmission lines on buried pipelines was established using CDEGS.The AC interference intensity and safety distance under typical transmission line characteristic parameters，pipeline parameters and laying environment parameters were calculated.Results showed that the AC interference voltage on the pipeline was directly proportional to the AC transmission current.When the parallel length between the 3PE pipeline and the transmission line was less than 20 km， the AC interference voltage was directly proportional to the parallel length.When the distance between the pipelines and transmission lines was small，the phase spacing and average height significantly impacted the AC interference voltage.As the distance increased， the AC interference voltage initially increased and then decreased.Based on extensive numerical simulations， a safety distance determination chart and AC interference voltage curve suitable for on-site engineering were proposed， providing a reference for selecting new pipeline routing and protecting existing pipelines from interference， thereby reducing the risk of AC interference on pipelines.