In recent years, the greenhouse effect and its management have received increasing attention. Sulfur hexafluoride is one of the important greenhouse gases, mainly used in electrical equipment, metal smelting, electronic manufacturing and atmospheric targets. As the main consumer industry of sulfur hexafluoride, in order to meet international environmental protection requirements, through research and technological improvements, the electronic manufacturing of sulfur hexafluoride gas and the use in atmospheric targets have basically stopped. In metal smelting, the use of mixed gases has also greatly reduced the content of sulfur hexafluoride, and it is still improving. For electrical equipment with the largest consumption, there is still little domestic environmental protection attention to sulfur hexafluoride, and electrical equipment itself is also constantly expanding the application of sulfur hexafluoride charging equipment.
SF6 has good insulation and arc extinguishing properties and is widely used in the power industry. Such as circuit breakers, high-voltage switches, high-voltage transformers, gas-sealed combination containers, high-voltage transmission lines, transformers, etc. Sulfur hexafluoride is also widely used in metal smelting. Atmospheric targets, electronic manufacturing and other industries because it is chemically inert, non-toxic, non-flammable and non-corrosive.
Sulfur hexafluoride (SF₆) is mainly used in the following aspects in the power industry:
1. Gas Insulated Switchgear (GIS)
Function: SF₆ is used as an insulating medium for gas insulated switchgear (GIS).
Advantages:
High dielectric strength, which can significantly reduce the size of the equipment.
Applicable to high and ultra-high voltage systems (such as above 110kV).
Suitable for places with limited space, such as urban substations.
2. High-voltage circuit breakers
Function: SF₆ is used as an arc extinguishing medium in high-voltage circuit breakers.
Advantages:
Excellent arc extinguishing performance, can quickly cut off large currents.
Prevent arc reignition and improve equipment safety.
Suitable for occasions with frequent operations.
3. Transformers and instrument transformers
Function: SF₆ is used in gas-insulated transformers and current/voltage transformers.
Advantages:
High insulation performance, reduced fire risk.
Oil-free design, environmentally friendly and simple to maintain.
4. Transmission lines
Function: SF₆ is used for gas-insulated transmission lines (GIL).
Advantages:
Suitable for long-distance power transmission, especially underground or in tunnels.
Low loss, high reliability.
5. Ring main unit and switch cabinet
Function: SF₆ is used for medium voltage ring main unit and switch cabinet.
Advantages:
Compact structure, space saving.
Applicable to urban power distribution network.
6. Other applications
Power capacitors: SF₆ is used in high-voltage power capacitors to improve insulation performance.
Laboratory equipment: SF₆ is used for insulation and arc extinguishing of high-voltage experimental equipment.
Summary of SF₆ advantages
High insulation strength: about 3 times that of air, reducing equipment size.
Excellent arc extinguishing performance: suitable for high voltage and high current applications.
Chemical inertness: not easy to react with other substances, high stability.
No fire risk: non-flammable, high safety.
Precautions
Environmental impact: SF₆ is a potent greenhouse gas, and leakage and recycling must be strictly controlled.
High cost: SF₆ equipment requires a large initial investment, but the long-term operation and maintenance costs are low.
