Study on the Position of an AC Interference Grounding Bed Under Dynamic Interference of an Electrified Railway

The co-existence of high-speed railways and buried pipelines may lead to stray current interference, posing a serious threat to pipeline safety. Existing protection design usually focuses only on the most severe interference case and does not adequately consider the dynamic variation caused by changing train positions. In this study, a numerical model of a high-speed railway–pipeline system was established to analyze the AC interference characteristics under different train positions. The midpoint positions between the traction power substation and the first autotransformer station (TPSS–AT1) and between the first and second autotransformer stations (AT1–AT2) were identified as the critical train locations for dynamic AC interference mitigation design. The novelty of this study lies not in developing a new electromagnetic solver but in identifying representative train positions for dynamic AC interference mitigation design and establishing a simplified grounding-bed design strategy for single-train operating conditions. Based on these two representative cases, the proposed strategy can satisfy the protection requirements for all train positions under the single-train operating condition. The results provide a practical reference for pipeline AC interference protection in similar railway–pipeline systems.