Pure Air/Nitrogen Insulated SF6-Free Ring Main Unit 24kV
Key attributes
| Brand | ROCKWILL |
| Series | REC |
| Rated maximum voltage | 24kV |
| Rated maximum current | 630/1250 A |
| ated frequency | 50/60 |
| Method of Insulation | Pure air/Nitrogen |
Description
The Rockwill 24 kV SF6-free ring main unit (RMU) is a fully sealed, maintenance-free gas-insulated switching assembly for three-phase AC 50/60 Hz secondary distribution networks. It uses high-purity synthetic pure air or nitrogen instead of sulphur hexafluoride, delivering full 24 kV insulation strength with a global-warming potential (GWP) of zero.
Designed and type-tested per IEC 62271-200:2021 and IEC 62271-1:2017, it combines vacuum arc suppression and a rotating three-position switch in a compact, eco-friendly unit for utilities, industry and commercial buildings.
Product Showcase Video
Service environment
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Air temperature: Maximum temperature: +55℃;
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Minimum temperature: -40℃
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Humidity: Monthly average humidity 95%;
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Daily average humidity 90%.
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Above sea level: Maximum installation altitude: 2500m or higher.
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Ambient air not apparently polluted by corrosive and flammable gas, vapor etc. No frequent violent shake
Main technical parameters (three phase)
| N | Item | Unit | Data |
|---|---|---|---|
| 1 | Rated maximum voltage | kV | 24 |
| 2 | Rated maximum current | A | 630/1250 |
| 3 | Rated frequency | Hz | 50/60 |
| 4 | Method of Arc Suppressing | / | Vacuum |
| 5 | Method of Insulation | / | Pure air/Nitrogen |
| 6 | Rated short circuit breaking current | kA | 20/25 |
| 7 | Rated peak value withstand current | kA | 50/63 |
| 8 | Rated 1min power frequency withstand voltage | kV | 65/79 |
| 9 | Rated lightning impulse voltage | kV | 125/145 |
| 10 | Operation sequence | / | C-0.3-CO-180-CO |
| 12 | Resistance loop | μΩ | ≤140 |
| 13 | Rated gas pressure (20℃ gauge) | Mpa | 0.02 |
| 14 | Minimum operating gas pressure | Mpa | 0 |
| 15 | Mechanical life | / | / |
| Circuit breaker | N | 10000 | |
| Load break switch | N | 3000/6000 | |
| Disconnector | N | 3000/6000 | |
| Earthing switch | N | 3000/6000 | |
| 16 | Protection grade | / | / |
| Gas tank | / | IP67 | |
| Shell | / | IP4X | |
| 17 | Rated annual air leakage rate | % | 0.01 |
Features of 630A Core Components
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Safety and Reliability
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a. The switch is equipped with clearly visible "double" isolation gaps, providing enhanced safety and reliability.
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b. The primary circuit features a clean design with a uniformly distributed electric field structure, ensuring excellent electrical performance.
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Compact Design
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The switch features a compact size. When installed in the air tank, the tank width can be as narrow as 500 mm. Filled with a suitable amount of SF6 gas, the switch’ s insulation performance fully complies with both the GB National Standard and the IEC International Standard requirements.
3D View
Documentation Resource Library SF₆-Free Ring Main Unit
FAQ for SF₆-Free Ring Main Unit
The REC series replaces traditional sulfur hexafluoride with high-purity, low-moisture synthetic pure air or nitrogen as the insulation medium. This SF6-free ring main unit eliminates greenhouse gas emissions and aligns with global green grid standards while maintaining high insulation strength and weather resistance.
Q:How does the SF6-free ring main unit ensure a long service life in harsh conditions？
A:This SF6-free ring main unit features an operating mechanism treated with zinc inlay alloy surface technology, which has passed over 168 hours of salt spray testing. The vacuum interrupter uses a soft encapsulation casting process, allowing for a mechanical life of up to 30,000 operations even in temperatures ranging from -40°C to +55°C.
Q:What safety features are integrated into the 630A core of this SF6-free ring main unit？
A:Safety and reliability are prioritized through the use of clearly visible "double" isolation gaps, allowing operators to verify the system status easily. Furthermore, the SF6-free ring main unit is designed with an optimized electric field distribution that keeps partial discharge levels below 5pC, ensuring excellent electrical performance.
Q:Is the SF6-free ring main unit suitable for space-constrained urban installations？
A:Yes, the SF6-free ring main unit features a highly compact design. When installed in the air tank, the cabinet width can be as narrow as 500 mm. This space-saving structure makes it an ideal solution for secondary distribution in crowded urban areas, industrial sites, or high-altitude locations up to 2500m.
