基于混合气体热特性的GIL氮气使用配比研究

SF₆/N₂混合气体具有绝缘性能良好、环境效益好等优点，被认为是能替代SF₆的最具发展前景的气体之一，但SF₆/N₂混合气体在不同场景下的混合比问题尚缺乏研究。文中在保证气体绝缘输电线路(GIL)绝缘水平的前提下，建立多物理场耦合计算模型，从混合气体热特性的角度出发，分析不同绝缘气体压强、负载电流和环境温度下SF₆/N₂混合比与GIL温升之间的关系，为GIL在不同场景下选择合适的SF₆/N₂混合比提供依据。结果表明：绝缘气体压强和相同压强下SF₆含量均与GIL温升呈负相关关系；设备的负载电流长期超过3 kA时，建议SF₆含量为40%～60%;设备运行在中低纬度地区时，建议SF₆含量为40%～70%,运行在高纬度地区时，建议SF₆含量为30%～40%。此外，由于设计GIL设备时考虑了安全裕度，因此通常SF<...

N2 proportion in GIL based on heat characteristics of gas mixture

SF₆ has problems such as high global warming potential and high price, so SF₆/N₂ with good insulation performance and environmental friendliness is considered to be the most promising SF₆ replacement gas at present. Under the premise of ensuring the insulation level of gas-insulated transmission lines, researching the thermal characteristics of SF₆/N₂ mixed gas and determining the mixing ratio of SF₆/N₂ under different conditions is of great significance for reducing the amount of SF₆ used and reducing the environmental impact of power equipment. In this paper, a 3D GIL model for coupled electromagnetic-fluid-temperature fields is developed using finite element analysis. By varying the SF₆/N₂ mixing ratio, insulating gas pressure, load current and ambient temperature, the thermal characteristics of the GIL under different operating conditions are obtained to determine the relationship between the SF₆/N₂ mixing ratio and temperature rise. The simulation results provide a basis for choosing a suitable SF₆/N₂ mixing ratio for the GIL, which has a good engineering application prospect and is of great significance for reducing the use of SF₆ and reducing the impact of power equipment on the environment.#$NLKeywords: GIL; SF₆/N₂ gas mixture; gas insulation; finite element method; thermal characteristics research