The "replacement trend" of SF6 load switches has arrived, don't buy the wrong one!

2025-08-26 14:23:01

If you are still hesitating whether to choose traditional SF6 Load switches for next year's distribution equipment procurement plan, this article will provide you with key decision-making basis. In 2025, the global market for environmentally friendly power equipment is expected to experience explosive growth. Early deployment is not only related to corporate social responsibility, but also directly affects the full lifecycle cost and operational risks of projects.

01 Why must we pay attention to SF6 substitution? Dual drive of policy and market

SF6 gas has been widely used in power switchgear in the past few decades due to its excellent insulation and arc extinguishing performance. However, SF6 is an extremely strong greenhouse gas with a global warming potential (GWP) 25200 times that of carbon dioxide and a lifespan of up to 3200 years in the atmosphere.

With the advancement of the global "dual carbon" strategy, the use of SF6 gas has been increasingly restricted. The Kyoto Protocol has explicitly required the gradual reduction and eventual ban of this gas. Many power grid companies, including State Grid Corporation of China, will no longer purchase distribution switchgear containing SF6 gas from the second half of 2023.

This means that continuing to purchase traditional SF6 equipment may face policy obsolescence risks, increased carbon tax costs, damage to corporate ESG ratings, and secondary investments resulting from future equipment replacement.

02 Who are the future mainstream of the three major alternative technology routes?

At present, the main alternative technology routes explored by the industry are as follows:

1. Vacuum arc extinguishing+environmentally friendly gas insulation (mainstream mature route)

This is currently the most mature and widely used solution in the medium voltage field. Use a vacuum arc extinguishing chamber to interrupt the current (solve the arc extinguishing problem), and use environmentally friendly gases (such as dry air, nitrogen) or natural gas as insulation media (solve the insulation problem).

Advantage:

Truly environmentally friendly: achieving zero greenhouse gas emissions.

Reliable technology: Vacuum breaking technology is mature, with strong breaking ability and long service life (mechanical service life can reach 10000 times).

Maintenance free: Vacuum arc extinguishing chambers are usually maintenance free throughout their entire lifecycle.

Application: Currently widely used in fields such as 40.5kV and 72.5kV, and has developed towards higher voltage levels of 145kV and above.

2. Pure vacuum insulation (cutting-edge technology)

Completely abandon any gas insulation medium and rely solely on vacuum and solid insulation materials. This is the ultimate solution in terms of technology, but it requires extremely high standards for craftsmanship and materials.

Advantages: Absolute environmental protection, no risk of gas leakage.

Challenge: Currently, insulation and heat dissipation in the medium voltage level and high voltage field (such as 145kV) are huge challenges.

3. SF6 gas mixture (transition plan)

Mixing other gases (such as nitrogen) in SF6 to reduce the amount of SF6 used in the short term.

Advantages: Smooth technological transition and relatively easy modification of existing equipment.

Disadvantage: Unable to completely solve environmental problems, there is still a greenhouse effect. This is more like a transitional solution rather than an ultimate solution.

03 Procurement Decision Guide: Key Considerations for Selection in 2025

When facing alternative technologies, procurement should shift from solely focusing on price to assessing total cost of ownership (TCO) and system reliability.

1. Voltage level and breaking capacity

12-40.5kV: Vacuum+dry air/nitrogen insulation technology is very mature and is the preferred choice.

72.5-145kV: Vacuum+clean air/environmentally friendly gas insulation is the mainstream development direction, and commercial products have already been developed.

252kV and above: Research and development are being intensified both domestically and internationally.

2. Benchmarking of key performance parameters

Insulation level: Ensure that the power frequency and lightning impulse withstand voltage of the new equipment is not lower than that of the original SF6 equipment.

Rated current and breaking capacity: The vacuum arc extinguishing chamber has strong short-circuit breaking current capacity, and it is necessary to verify whether the rated parameters meet the system's short-circuit capacity requirements (such as 40kA).

Mechanical lifespan and reliability: It is required that the mechanical lifespan be ≥ 10000 times, and the reliability data of core components (such as vacuum arc extinguishing chambers) should be understood.

3. Environmental adaptability

Temperature range: Environmentally friendly equipment needs to adapt to harsh environments ranging from -50 ° C to+55 ° C.

Altitude: Verify whether the equipment is suitable for high-altitude areas (some products are suitable for altitudes up to 6000m).

4. Cost structure analysis

5. Supply Chain and Standard Certification

Choose suppliers with clear technical routes and stable mass production capabilities to avoid becoming "guinea pigs".

Confirm that the product has passed the full set of type tests and obtained an appraisal report from authoritative institutions (such as Xigao).

Check for compliance with IEC/GB standards and fluorine free certification.

04 Global Case: Why did they choose to replace?

China Southern Power Grid: In 2025, a 145 kV GIS provided by a certain company was put into operation at the 110 kV Xinan substation in Shantou, Guangdong. This device uses environmentally friendly mixed gases instead of SF6, reducing greenhouse gas emissions by over 99% while maintaining the same compact size and reliability as traditional equipment.

Sweden's E.ON power company: Replace its SF6 medium voltage switchgear with SF6 free equipment. This move helps it move towards the goal of fossil fuel free by 2025, eliminate gas recovery costs, and reduce maintenance and replacement costs.

Wuhan Daoluokou 220kV Substation in China: A batch of 126kV insulation vacuum breaking environmental protection GIS developed by Special Transformer Electric has been put into operation. This is the world's largest commercial case, expected to reduce approximately 100000 tons of carbon dioxide equivalent emissions throughout its entire lifecycle.

Conclusion: Strategic Transformation of Procurement

In 2025, procurement decisions must go beyond the primary mode of "unit price comparison". Choosing SF6 alternative solutions is not only a technical choice, but also a comprehensive reflection of risk avoidance, cost optimization, and corporate social responsibility.

Action suggestion:

1. For new projects: Directly purchase vacuum+environmentally friendly gas insulation equipment to avoid future policy risks.

2. For renovation projects: prioritize overall replacement over repair, and use new equipment to save space and maintenance costs.

3. Supplier communication: Request to provide a full lifecycle TCO analysis report and third-party certification documents.

The future is here, and those companies that embrace green technology early on will gain dual leadership in cost control and social responsibility.