Analysis of the thermal environment and concentration of escaping gas in the GIL pipe gallery
This article focuses on a Gas Insulated Transmission Line(GIL)underground pipe gallery as the subject of study.It establishes physical and mathematical models of the gallery using FLUENT software,implements appropriate ventilation systems,and defines suitable initial and boundary conditions for the space within the pipe gallery.Existing studies typically consider the four walls of the pipe gallery as insulated conditions.In contrast,this paper innovatively analyzes the heat transfer between the GIL pipe gallery and the surrounding soil.It explores the impact of natural air intake and mechanical exhaust ventilation methods on the temperature field of the GIL underground pipe gallery under various operating conditions in both winter and summer.Additionally,this study simulates and analyzes the concentration distribution of SF6 gas within the cable following normal or accidental leakage.It is important to note that most existing references and studies treat the four walls of the pipe gallery as adiabatic conditions.This article examines the heat transfer between the GIL pipe gallery and the surrounding soil.The results indicate that the ventilation and heat dissipation within the pipe gallery are less effective in summer compared to winter,with local temperatures around the cable at the end of the pipe gallery reaching 42 ℃.Although this temperature does not meet regulatory requirements,it remains within an acceptable range.The heat dissipation of cables under abnormal working conditions is higher than that under normal conditions,resulting in reduced ventilation effectiveness during such periods.Therefore,regular inspections are necessary.The lower section of the pipe gallery is equipped with SF6 gas exhaust vents,allowing for the timely discharge of leaked gas and ensuring a safe operating environment for maintenance personnel.The findings of this study reveal the distribution patterns of temperature and gas concentration within the GIL pipeline gallery,providing a theoretical foundation and technical support for maintaining the safe and stable operation of the system.