Safety Evaluation Method for Pipelines Crossing or Parallel with AC Transmission Lines

High voltage AC transmission lines generate AC interference on buried pipelines through electromagnetic induction, causing AC corrosion in buried pipelines. Understanding the interference laws of transmission lines on pipelines and mastering the safety evaluation methods for transmission lines and pipelines can enable them to be designed reasonably from the selection stage, avoiding or reducing the interference problems that may occur during pipeline operation. A numerical simulation model was established to calculate the AC interference of AC transmission lines on buried pipelines. The interference law of three-phase layout and phase spacing of AC transmission lines on pipelines was studied, and typical transmission line levels and critical distances between transmission lines and pipelines at different intersection angles were determined. The results show that when the three-phase was arranged horizontally, the pipeline interference voltage was the highest, and the pipeline interference voltage increased linearly with the phase spacing. The higher the voltage level of the transmission line, the greater the critical distance required. The smaller the intersection angle between transmission lines and pipelines, the greater the critical distance required. The intersection angle limited varies depending on the transmission level and length of the transmission line. And based on this, a critical distance map and safety evaluation method were established, simplifying the determination of critical distance.