With the continuous expansion of national ultra-high voltage engineering construction scale

the construction of ultra-high voltage substations in cold regions is gradually becoming normalized. The ambient temperature in some areas is close to -40 ℃. The SF

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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 SF

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gas liquefaction by analyzing the low-temperature characteristics of SF

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gas and combining it with product structure. For components 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 SF

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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 effectiveness of auxiliary heating devices in improving SF

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gas temperature

the reliability of various components in 1 100 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.