RMU (Ring Main Unit) is a medium-voltage (typically 12kV–24kV) switchgear device designed for urban power distribution, industrial parks, and commercial buildings. Unlike SF6 RMUs that use sulfur hexafluoride as an insulating medium, it adopts dehumidified dry air (moisture content ≤ 50ppm, dew point ≤ -40°C under standard pressure) as the core insulating and arc-extinguishing medium, aligning with low-carbon and environmental protection trends.
Performance Advantages
1. Environmental Friendliness: Dry air is non-toxic, non-greenhouse (GWP=0, ODP=0), avoiding SF6's environmental risks (high global warming potential, 23,500 times that of CO2). It requires no special recycling or disposal processes.
2. Safety & Reliability: No risk of SF6 leakage or decomposition toxins; the positive-pressure sealed structure prevents dust, salt spray, or insects from entering, making it suitable for harsh environments(e.g., coastal areas, industrial zones with heavy dust).
3. Low Maintenance: Dry air has stable chemical properties ( no corrosion to metal parts); maintenance mainly involves periodic air pressure checks and replenishment (interval 2-3 years, far simpler than SF6 gas detection).
4. Cost-Effectiveness: Eliminates costs for SF6 gas purchase, recycling, and leak repair; the dry air supply system(dehumidifiers) has low long-term operation costs.
Technical Parameters:
| Rated Current |
630A |
| Design |
Modular Design |
| Standards Compliance |
IEC 62271-200 / ANSI |
| Installation Type |
Indoor / Outdoor |
| Short Circuit Withstand |
25kA To 50kA |
| Protection Degree |
IP4X |
| Control Voltage |
24 V / 48 V / 220 V (110 V On Request) |
| Current |
630A, 1250A |
| Number of Poles |
3 |
| Weight |
Varies From 500kg To 3000kg |
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