Hexafluo’s C4F7N Contributes to the Successful Operation of the World’s First 550 KV SF6-Free Gas Insulated Line (GIL)

In June 2025, the world’s first 550 KV SF6-Free gas-insulated line (GIL) adopting C4F7N (abbreviated as C4 gas) was officially put into operation at the 500 KV Rongsheng Substation in Anqing, Anhui Province. This project marks another landmark breakthrough for Pinggao Electric in the field of SF6-Free power equipment.

[The world’s first 550 KV C4F7N eco-friendly GIL (SF6-Free) running live at 500 kV Rongsheng Substation, Anqing. Photo by Xu Xiaoxiao]

This project adopts Hexafluo’s C4F7N gas mixture as the insulating medium for power transmission equipment. Joint research conducted by Pinggao Electric, China Electric Power Research Institute, State Grid Anhui Electric Power and other partners has overcome core technical challenges including insulation and temperature rise of transmission equipment using C4F7N gas, enabling the successful development of the 550 KV SF6-Free GIL unit.

In November 2024, the Ministry of Ecology and Environment of China officially approved the 11th batch of regular registrations for non-existing chemicals, and Hexafluo obtained the official registration certificate for the manufacturing of C4F7N.

Compared with sulfur hexafluoride (SF₆), the greenhouse effect of C4F7N gas mixture is reduced by 97%. The equipment maintains identical dimensions, technical parameters and performance as conventional 550 KV SF₆-based gas insulated transmission lines, and is compatible with SF₆ and SF₆/N₂ gas mixture. It delivers an optimal solution for SF6 replacement renovation of existing substations and construction of new power stations, significantly elevating the eco-friendly upgrading of power transmission and distribution in China and making vital contributions to the strategic "carbon peaking and carbon neutrality" goals.

Hexafluo independently develops eco-friendly synthetic production method with a full industrial supply chain, covering the mass production of C4F7N pure gas, customized C4F7N gas mixture, precise quality control tests and closed-loop waste gas recovery. Our products are already supplied to leading power equipment manufacturers worldwide on large basis and are widely recognized by global customers.

As a leading manufacturer of C4F7N, Hexafluo sticks to the philosophy of "Innovation-Driven, Sustainable Development". With self-developed technology and one-stop professional delivery service, we supply high-quality C4F7N products and comprehensive low-carbon insulating gas solutions for global customers. We look forward to cooperating with all partners from the power industry for a low-carbon and sustainable future.