In January 2017, the first themed seminar on environmentally friendly gas alternatives was held by Xi Dian, with nearly 300 participants in attendance. Shanghai Kestone also released a paper at the event.
In recent years, through participation in numerous high-voltage electrical technology seminars, the environmental protection theme has gained widespread recognition.
As for future trends, the phasing-out of SF₆ has become an industry consensus.
This paints a blueprint for the future.
In recent years, the SF₆ replacement drive has advanced rapidly, with the industry basically "crossing the river by feeling the stones" and moving forward step by step. Official guidelines for SF₆/N₂ gas mixtures were issued in late 2022, accelerating their rollout in the 110–220 kV range. Currently, 80% of new 110 kV substations under State Grid and China Southern Power Grid use SF₆/N₂ mixtures, versus around 20% for 220 kV ones.
Dry air or nitrogen is also fast gaining traction for 10–35 kV systems; positive progress has been made in applying dry air to 66 kV grids.
SF₆/N₂ mixtures are deemed a transitional solution, expected to last 5 to 10 years. The industry’s overarching direction, as pursued by experts, is clean air plus vacuum arc interruption—a long-term goal with a challenging path ahead.
The widespread promotion of C₄F₇N in China is questionable; it has not yet secured mainstream support for now. Domestically, C₄F₇N remains in the trial-and-report phase, with many enterprises conducting R&D and a handful of pilot projects connected to the grid annually. Players like Pinggao, Changgao, Baiyun, Sunny HV and Taikai HV are all engaged in related research and testing.
Our equipment business is thus aligned with this market stage. Hitachi Energy is the only enterprise mass-producing C₄F₇N products at present, primarily for overseas markets.
South Korea is promoting K6 gas.
Two distinct technical pathways exist: overseas, led by Hitachi Energy, the focus is on C₄F₇N-based mixtures; Siemens Energy is scaling clean air applications from 66 kV and 145 kV to higher voltage classes.
Current Supply and Future Trends of C4F7N GasAt present, manufacturers of C4F7N gas operate on an extremely small scale, with exorbitantly high prices.
3M has withdrawn from the market. Major domestic producers include Haohua, Haisifu, Yuji New Materials, and Ankura.
The largest production line to date is Yuji’s 100-ton capacity line, yet it has not reached its full production target.
Ankura‘s C4F7N gas project is also underway.