1100 kV GIS低温防液化设计方法及试验研究

Design Method and Experimental Research on Low⁃temperature Anti⁃liquefaction Measures for 1100 kV GIS

随着国家特高压工程建设规模的不断扩大,严寒地区建设特高压变电站也逐渐常态化。有些地区的环境温度接近-40℃。特高压开关设备的SF6绝缘气体在低温环境会发生液化,降低设备可靠性,需采取措施保证设备的绝缘性能。本文通过对SF6气体低温特性分析并结合产品结构,提出采用辅助加热装置防止SF6气体液化的设计方法;对于不能直接使用辅助加热装置的元件采取降低气压的方法防止液化;同时对低温环境下采用辅助加热装置后壳体内部SF6气体的温度变化、各主要元件低温下的密封性能、密度继电器的低温性能等进行了试验研究,验证了辅助加热装置对于提升SF6气体温度的有效性、1 100 kV GIS各元件低温下的可靠性以及辅助加热装置对产品温升的影响情况。试验结果将为后续低温地区特高压站的建设和运行提供指导。

With the continuous expansion of national ultra⁃high voltage engineering construction scale,the construc⁃tion of ultra⁃high voltage substations in cold regions is gradually becoming normalized.The ambient temperature in some areas is close to-40℃.The SF6 insulation gas of ultra⁃high voltage switchgear will liquefy in low⁃temperature environments,reducing equipment reliability.Measures need to be taken to ensure the insulation performance of the equipment.This article proposes a design method for using auxiliary heating devices to prevent SF6 gas liquefac⁃tion by analyzing the low⁃temperature characteristics of SF6 gas and combining it with product structure.For compo⁃nents that cannot be directly used with auxiliary heating devices,the method of reducing air pressure is adopted to prevent liquefaction.At the same time,experimental research was conducted on the temperature changes of SF6 gas inside the shell,the sealing performance of various main components at low temperatures,and the low⁃temperature performance of density relays after using auxiliary heating devices in low⁃temperature environments.The effective⁃ness of auxiliary heating devices in improving SF6 gas temperature,the reliability of various components in 1100 kV GIS at low temperatures,and the impact of auxiliary heating devices on product temperature rise were verified.The test results will provide guidance for the construction and operation of ultra⁃high voltage stations in low⁃temperature areas in the future.