The Environmentally friendly gas insulation RMU (Ring Main Unit) is a factory-assembled, sealed, metal-enclosed medium voltage switchgear (up to 24kV) that uses an eco-friendly gas mixture as its primary insulating and arc-quenching medium---instead of pure SF6. Unlike traditional SF6 RMUs which have a high Global Warming Potential (GWP = 23,500), SF₆ has a GWP of approximately 24,300 according to current EU reference data. Lugao Power’s eco-RMU utilizes either a synthetic air, N₂/SF₆ blend (with less than 10% SF6), or fluoroketone-based (C5-FK) gas. These gases are non-toxic, non-flammable, and have a GWP below 1 (for synthetic air) or under 600 (for C5-FK), compared to 23,500 for pure SF6.
Why Choose Lugao Power’s Eco-Gas RMU Over SF6 Alternatives?
|
Advantage |
Lugao Power Environmentally friendly gas insulation RMU |
Conventional SF6 RMU |
|
Global Warming Potential |
<1 to <600 (depending on gas blend) |
23,500 |
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Gas leakage impact |
Negligible environmental effect |
1kg SF6 = 23.5 tons CO₂ equivalent |
|
Regulatory readiness |
Compliant with EU F-gas ban (2026+), UK, China green standards |
Being phased out in many countries |
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End-of-life disposal |
Gas can be released to atmosphere (non-toxic) |
Requires costly SF6 recovery and recycling |
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Operator safety |
Non-toxic, non-flammable |
Non-toxic but heavy gas – can displace oxygen in confined spaces |
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Dielectric strength |
Equivalent to SF6 at same pressure (0.04-0.05 MPa) |
Reference standard |
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Temperature performance |
-25°C to +40°C (same as SF6) |
-25°C to +40°C |
Feature List with Technical Explanations
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Feature |
Description |
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Eco-gas insulation blend |
C5-FK (fluoroketone) mixed with CO₂ or synthetic air. GWP < 600, ODP = 0. No PFAS (per- and polyfluoroalkyl substances) concerns.The gas composition and environmental compliance should be evaluated according to the specific gas mixture, applicable regional regulations, and supplier documentation. |
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Sealed pressure system |
Stainless steel tank, helium leak tested (<1×10⁻⁶ mbar·L/s). No gas refill needed for life (≥30 years). |
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Three-position switch |
Integrated load break switch + earth switch in one compact mechanism. Positions: Closed / Open / Earthed. |
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Mechanical interlocks |
Prevents incorrect operations: cannot close earth switch unless main switch open; cannot open front cover when switch closed. |
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Visible isolation |
Viewing window shows switch blade position – no ambiguity. |
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Front access cabling |
All cable connections accessible from front – ideal for wall-mounted or back-to-back installations. |
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Pressure monitoring |
Gas density indicator with low-pressure alarm (optional remote signal). |
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Optional vacuum circuit breaker |
For transformer protection up to 1250A with electronic relay. |
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Partial discharge free |
<5pC at 1.2Ur – ensures long insulation life. |
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Internal arc tested |
IAC AFLR 20kA/1s – protects personnel even under fault conditions. |
Each Environmentally friendly gas insulation RMU is produced in our ISO 9001:2021 and ISO 14001 certified facility in Wenzhou, China. The manufacturing process is specifically adapted for eco-gas handling – different from SF6 production lines.
1. Tank fabrication
● 3mm stainless steel (AISI 304) – laser cut, robotic bent, welded by automated MIG process.
● 100% helium leak detection: Tank submerged in vacuum chamber; helium spray test – leak rate <1×10⁻⁶ mbar·L/s (20x stricter than IEC requirement).
2. Component assembly
● Three-position switch mechanism assembled in cleanroom (Class 100,000).
● Copper contacts silver-plated (15μm thickness) – ensures low contact resistance (<30μΩ).
● Shutter mechanism – stainless steel, cam-driven.
3. Vacuum processing
● Tank heated to 80°C under vacuum (<10 Pa) for 8 hours – removes moisture (target <10ppm).
● Prevents internal condensation and dielectric breakdown.
4. Eco-gas filling
● Gas mixture prepared in dedicated mixing station (accuracy ±1%).
● For C5-FK blend: C5-FK (fluoroketone) + CO₂ + O₂ (trace).
● Fill pressure: 0.04 MPa relative at 20°C.
● Each tank serial-numbered with gas composition label.
5. Final electrical testing
● Power frequency withstand: 42kV/1min (12kV units).
● Lightning impulse: 75kV peak (1.2/50μs).
● Partial discharge: <5pC at 1.2Ur (12kV = 14.4kV test voltage).
● Contact resistance measurement: Recorded on test certificate.
● Mechanical operation test: 50 open/close cycles – no gas pressure change.
6. Interlock verification
● All mechanical interlocks tested with gauge pins – force measurement recorded.
7. Packaging
● Gas-filled unit sealed with transport cap on valve.
● Pressure gauge protected with foam cover
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QC Hold Point |
Inspection Method |
Rejection Criteria |
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Raw copper |
Spectrometer analysis |
Conductivity <58 MS/m |
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Welded tank |
Dye penetrant test |
Any crack visible |
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After vacuum drying |
Moisture meter |
Dew point > -50°C |
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After gas filling |
Gas chromatograph |
Composition off by >2% absolute |
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Final HV test |
AC dielectric test set |
Flashover below 42kV |
12 months from commissioning date or 18 months from shipment date (whichever occurs first).
1. All mechanical parts (switch mechanism, interlocks, earth switch, indicators)
2. Gas tank integrity (leakage due to manufacturing defect)
3. Primary and secondary contacts
4. Eco-gas composition (if factory fill deviates from certificate)
5. Pressure gauge and density monitor
1. Damage from improper storage or installation (e.g., dropping the unit)
2. External corrosion due to aggressive environment (e.g., chemical plant)
3. Acts of nature (earthquake, flood, lightning)
4. Consumables (fuses, indicator lamps, batteries)
A: Lugao Power offers two options:
● Option A (economy): N₂ + 10% SF₆ blend – GWP ≈ 2,350 (still 90% lower than pure SF₆).
● Option B (green premium): C5-FK (fluoroketone) + CO₂ + O₂ – GWP < 600, no PFAS, suitable for projects seeking to reduce reliance on high-GWP SF₆ insulation gases..
Both are non-toxic, non-flammable, and approved by IEC 62271-200.
A: Yes，at the same operating pressure (0.04-0.05 MPa), the dielectric strength and arc-quenching capability are equivalent. Our environmentally friendly RMU passes the same type tests as SF6 units: 42kV withstand, 20kA short-circuit making, and 50 mechanical operations.
A: Eco-gas is non-toxic (unlike SF6 which can produce toxic byproducts under arcing). However, large leaks in confined spaces could displace oxygen. Lugao Power’s RMU includes a low-pressure alarm. If triggered, ventilate the room before entry. The gas itself is safe to breathe in small amounts (similar to CO₂ fire extinguisher discharge).
A: The tank is sealed for life---you should never need to refill under normal conditions (leak rate <0.1% per year). However, if a valve is damaged, Lugao Power provides refill kits with the exact gas mixture. We do not recommend using local SF6 – that would defeat the environmental purpose.
A: Initial purchase cost is approximately 8-12% higher due to the gas blend and dedicated production line. However:
1. You avoid future SF6 recovery costs
2. You qualify for green building tax incentives (e.g., in Singapore, EU).
3. Many utilities now pay a premium for SF6-free switchgear in their procurement scoring.
4. Over 20-year lifecycle, Lugao’s eco-RMU is cost-neutral or cheaper.
A: Full IEC 62271-200 type tests (KEMA certified). Additional:
● ISO 14001 (manufacturing environmental management)
● CE marking
● Chinese GB/T 3906
A: No，the gas handling system, seals, and pressure settings are different. However, Lugao Power’s gas-insulated RMU has the same external dimensions and busbar spacing as most standard SF6 RMUs. This allows “drop-in” replacement without civil works.
Lugao Factory
Address
No. 19, Keaisi Road, Xiangyang Industrial Zone, Liushi Town, Yueqing City, China
Tel
Share your specs: Voltage level (e.g., 11kV, 33kV), rated capacity (kVA/MVA), and installation environment (Indoor/Outdoor).
Our engineering review: We analyze your load profile and short-circuit requirements (2-4 hours).
Deliverables: You'll receive a preliminary GA drawing, technical datasheet, and commercial offer within 24 working hours.
