A research team at Zhengzhou University's (ZZU) Henan Engineering Research Center of Power Transmission & Distribution Equipment and Electrical Insulation has developed a new generation of eco-friendly high-voltage switches that could significantly reduce the use of sulfur hexafluoride (SF6), a potent greenhouse gas.
The 145 kV intelligent vacuum arc extinguishing type environmental protection gas insulated switchgear. [Photo/zzu.edu.cn]
For decades, SF6 has been widely used in high-voltage switches due to its superior arc-extinguishing and insulating properties. However, its global warming potential is more than 24,000 times that of CO2, making even small leaks a long-term climate concern.
Led by Professor Cheng Xian, the team began tackling this challenge in 2013. Instead of searching for a direct gas replacement — which had proven difficult due to toxicity or poor performance — they developed an innovative solution combining series-connected vacuum interrupters with environmentally friendly gas insulation.
Professor Cheng Xian introduces the team's study. [Photo/zzu.edu.cn]
A breakthrough came with the self-voltage-balancing design, which ensures each vacuum interrupter shares voltage evenly. This solved a long-standing limitation of vacuum technology at higher voltages. The team also developed online monitoring systems to track vacuum integrity and detect insulation defects, significantly improving reliability.
The technology has been adopted in projects across China, as well as in countries including Saudi Arabia and Cambodia. To date, it has reduced SF6 use by 462 metric tons, equivalent to reducing CO2 emissions by approximately 11.64 million tons.
The team is now working to adapt the technology to ultra-high voltage levels, aiming to achieve full replacement across the entire power grid.
Professor Cheng Xian introduces the team's study. [Photo/zzu.edu.cn]