The successful development of China’s first 145kV Gas-Insulated Switchgear (GIS) using a C4-FN (perfluoroisobutyronitrile) gas mixture marks another significant milestone in the evolution of high-voltage power equipment.
For decades, SF₆ has been the preferred insulating and arc-quenching gas for GIS because of its exceptional dielectric strength and switching performance. However, increasing environmental regulations and global carbon reduction goals are accelerating the search for alternative insulating gases with much lower greenhouse impacts.
The introduction of 145kV C4-FN GIS demonstrates that eco-friendly insulating gases are moving beyond laboratory research into practical grid applications.
SF₆ remains one of the most effective insulating gases used in electrical power systems. Its excellent insulation capability and arc-quenching performance have made it the industry standard for decades.
However, SF₆ also has one major disadvantage—its extremely high Global Warming Potential (GWP), approximately 24,300 times greater than CO₂ over a 100-year period.
As governments and utilities continue pursuing carbon neutrality, reducing SF₆ emissions has become an important objective worldwide. Rather than replacing existing equipment immediately, manufacturers are developing environmentally friendly insulating gases for future GIS projects.
Among several alternative gases currently under development, C4-FN has attracted considerable attention.
Instead of being used alone, C4-FN is typically blended with gases such as CO₂ and O₂, creating a gas mixture that offers an excellent balance between insulation performance and environmental sustainability.
Compared with conventional SF₆, C4-FN mixtures offer several advantages:
- Significantly lower greenhouse impact
- High dielectric performance suitable for high-voltage GIS
- Compatibility with modern GIS designs
- Strong potential for large-scale commercial deployment
These characteristics have made C4-FN one of the leading candidates for next-generation gas-insulated switchgear.
While environmentally friendly gas mixtures reduce environmental impact, they also introduce new requirements for equipment commissioning and maintenance.
Unlike pure SF₆ systems, C4-FN gas mixtures depend on carefully controlled gas composition, pressure, and moisture levels. Even small variations may affect insulation performance.
As a result, utilities and maintenance teams require more advanced gas handling technologies throughout the equipment lifecycle.
Key maintenance tasks include:
- Gas composition verification
- Dew point measurement
- Leak detection
- Gas recovery and recycling
- Vacuum evacuation before gas filling
- Safe gas filling during commissioning
Reliable gas management becomes just as important as the insulating gas itself.
As eco-friendly GIS technology becomes more widely adopted, gas handling equipment must evolve alongside it.
Future maintenance will require equipment capable of safely handling both conventional SF₆ and new environmentally friendly insulating gas mixtures.
This includes:
Accurate leak detection helps prevent gas loss, supports environmental compliance, and ensures long-term equipment reliability.
Recovering and recycling insulating gases minimizes emissions while reducing operating costs.
Gas analysis verifies gas quality by measuring parameters such as gas composition, moisture content, and other key indicators that influence insulation performance.
Proper vacuum treatment removes moisture and contaminants before gas filling, helping maintain the designed dielectric strength of the equipment.
For many years, KSTONE has specialized in SF₆ gas leak detection and gas handling equipment for high-voltage electrical applications.
As the industry moves toward environmentally friendly insulating gases, KSTONE has expanded its product portfolio to support both traditional SF₆ equipment and next-generation C4-FN gas mixtures.
Our solutions include:
- Leak detectors for SF₆ and C4-FN insulating gases
- Gas handling and recovery equipment for C4-FN gas mixtures
- Gas analysis solutions for gas composition and dew point measurement
- Vacuum evacuation and gas filling equipment for GIS installation and maintenance
By continuously investing in research and development, KSTONE is helping utilities and service providers adapt to the changing requirements of sustainable power systems.
The successful deployment of China’s first 145kV C4-FN GIS is more than a technological achievement—it signals the direction of the future power industry.
Although SF₆ will continue to play an important role for many years, environmentally friendly insulating gases are expected to become increasingly common in newly built substations and transmission projects.
For manufacturers, utilities, and maintenance providers, this transition is not only about adopting new gases but also about upgrading the technologies used to detect, analyze, recover, and manage them safely and efficiently.
As this transformation continues, reliable gas handling solutions will remain essential to ensuring the safety, performance, and sustainability of next-generation GIS equipment.