## 6 Conclusions  
The current research on overvoltage of adjacent pipelines caused by lightning strikes on overhead lines only focuses on the situation of lightning strikes on towers. When a lightning strike occurs on the conductor and causes the insulator to flashover, there is grounding scattered current on both sides of the lightning strike point. This scattered lightning current can also generate pipeline overvoltage on the natural gas pipeline at the intersection. Additionally, to prevent excessive design of pipeline overvoltage protection measures, this paper presents the optimal length term equation of bare copper wire for a solid-state decoupling device. The conclusions of this study are as follows:  
1. As the lightning peak current increases, there is an upward trend observed in the induced voltage of the metal layer, the induced voltage of the insulation layer, and the withstand voltage of the insulation layer in natural gas pipelines. Specifically, when the lightning peak current increases from 25 kA to 50 kA, the withstand electric potential of the insulation layer increases by 108.96%.
2. The induced voltage of the metal layer, the induced voltage of the insulating layer, and the withstand electric potential of the insulating layer of the natural gas pipeline exhibit an upward trend with increasing soil resistivity. As the soil resistivity increases from 200 \(\Omega\) m to 1500 \(\Omega\) m, the electric potential of the insulating layer increases by 72.94%.
3. As the spacing between the \"pipeline\" increases, the induced voltage of the metal layer, the induced electric potential of the insulating layer, and the withstand electric potential of the insulating layer of the natural gas pipeline gradually decrease.
4. In situations where there is scattered lightning current in the ground, the voltage of the pipeline's insulation layer can be reduced by using a solid-state decoupling device, a bare copper wire, and a specific connection mode. When the length of the bare copper wire is increased from 0 m to 80 m, the voltage amplitude of the pipeline's insulation layer decreases by 1.78 kV.  
Conceptualization, W.L. and Z.J.; methodology, Y.H. and H.T.; software, H.T.; validation, H.T. and W.L.; formal analysis, Y.H.; investigation, X.S. and Y.H.; resources, X.S.; data curation, Y.H.; writing--original draft preparation, H.T.; writing--review and editing, Y.H.; visualization and supervision, J.X. and W.S.; project administration, Y.W.; funding acquisition, Z.J. All authors have read and agreed to the published version of the manuscript.  
Figure 17: The influence curve of bare copper wire length on soil potential in the research path.  
**Funding:** This project is supported by the State Grid Hubei Electric Power Co., Ltd. Science and technology project. grant number (B315F0222836).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are available in article.  
**Acknowledgments:** The authors would like to express sincere thanks to the Science and Technology Research Institute, National Oil and Natural Gas Pipeline Network Group Company Limited, and CNPC Engineering Materials Research Institute Co., Ltd., State Key Laboratory of Service Behavior and Structural Safety of Petroleum Pipe and Equipment Materials.  
**Conflicts of Interest:** The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] are employee of State Grid Hubei Power Supply Limited Company Ezhou Power Supply Company, who provided funding and teachnical support for the work. The funder had no role in the design of the study; in the collection, analysis, or interpretation of data, in the writing of the manuscript, or in the decision to publish the results.