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A Ring Main Unit (RMU) is a compact, factory-assembled medium-voltage switchgear system used to control, protect, and isolate power distribution networks. It is typically installed in ring or radial distribution systems, allowing electricity to be supplied from multiple directions to ensure high reliability.
Lugao Ring Main Units are designed for 11kV, 12kV, 15kV, 24kV, and up to 40.5kV systems and are widely used in urban power grids, industrial facilities, renewable energy projects, and compact substations.
Unlike traditional open switchgear, Ring Main Units are sealed, space-saving, and maintenance-friendly, making them ideal for modern power distribution where safety, continuity, and efficiency are critical.
Controls power flow between feeders and enables flexible network operation without service interruption.
Safeguards downstream equipment from overloads, short circuits, and earth faults using reliable protection devices.
Allows faulty sections to be safely isolated, ensuring secure maintenance and fast fault location.
Reduced outage time, safer operation, and improved grid reliability.
Ring Main Unit enable fast power rerouting during faults or maintenance, minimizing downtime—especially critical for hospitals, data centers, and industrial users.Avoids costly production losses and service interruptions.
With a small footprint and front-access operation, Ring Main Units are perfect for locations with limited space such as urban substations, underground installations, and commercial buildings.
Fully sealed live parts
Arc-resistant design options
Excellent moisture, dust, and corrosion protection
Protects operators and nearby infrastructure even in harsh environments.
4. Energy Efficiency & Low Losses
High-quality copper busbars, precision insulation systems, and optimized current paths reduce energy losses and heat generation.
Uses SF₆ gas insulation
Fully sealed and maintenance-free
Extremely compact and reliable
Best For:
Urban substations, coastal or high-humidity areas, renewable energy plants.
Uses air as insulation medium
Lower initial cost
Easy access for inspection and repair
Best For:
Cost-sensitive projects with adequate installation space.
Traditional insulation method
Mostly used in legacy systems
Gradually replaced by GIS/AIS RMUs
Note:
Lugao mainly recommends GIS or AIS Ring Main Unit for modern projects due to higher safety and lower maintenance.
Rated voltage: 11kV – 40.5kV
Rated current: up to 630A
Short-circuit withstand: up to 20–25kA
Modular feeder configurations
Optional intelligent protection & SCADA interfaces
IEC & ANSI compliant designs
Power Utilities: Distribution networks and substations
Industrial Plants: Steel, mining, chemical, manufacturing
Renewable Energy: Solar farms, wind farms, microgrids
Commercial Buildings: Malls, hospitals, airports, offices
Data Centers: Stable, uninterrupted power supply
Specialized in medium-voltage power equipment
Strong R&D and engineering team
Stable quality system certified by ISO9001 & SGS
Designed according to IEC 62271
Meets global grid acceptance requirements
Voltage & current ratings
Feeder combinations
Protection relays & communication protocols
OEM / ODM branding support
Lugao Ring Main Units are exported to Africa, Southeast Asia, the Middle East, Central Asia, and Europe, serving utilities and EPC contractors worldwide.
Before purchasing an RMU, consider:
System Voltage & Current Requirements
Insulation Type: GIS vs AIS
Installation Environment: indoor / outdoor, humidity, dust
Protection & Automation Needs
Future Expansion Capability
Our engineers provide free technical consultation, drawings, and selection support to reduce procurement risks.
Q1: What’s the difference between Ring Main Unit and conventional switchgear?
RMUs are compact, sealed, and designed for ring networks, while conventional switchgear is larger and requires more maintenance.
Q2: Are Lugao RMUs maintenance-free?
GIS RMUs are virtually maintenance-free; AIS RMUs require minimal routine inspection.
Q3: Can RMUs integrate with SCADA systems?
Yes. Lugao RMUs support intelligent monitoring, protection relays, and communication interfaces.
Q4: Do you support OEM & ODM customization?
Yes. We offer full customization including structure, control logic, branding, and technical parameters.
