Ring Main Unit（RMU）
Engineered for reliable and sustainable power distribution, our Air Insulated Switchgear (AIS RMU) provides a highly dependable, cost-effective, and 100% SF6-free solution for medium voltage secondary networks. Utilizing ambient air as the primary insulation medium and vacuum technology for arc quenching, this switchgear eliminates greenhouse gas regulations and reduces end-of-life disposal costs.
Designed strictly to IEC 62271-200 standards, our AIS features a modular and extensible architecture, allowing for flexible configurations using Load Break Switches (LBS), Vacuum Circuit Breakers (VCB), and fuse combinations. It is the ideal choice for indoor substations, commercial buildings, and industrial facilities where space allows and budget optimization is key.
Product Description
Engineered for reliable and sustainable power distribution, our Air Insulated Switchgear (AIS RMU) provides a highly dependable, cost-effective, and 100% SF6-free solution for medium voltage secondary networks. Utilizing ambient air as the primary insulation medium and vacuum technology for arc quenching, this switchgear eliminates greenhouse gas regulations and reduces end-of-life disposal costs.
Designed strictly to IEC 62271-200 standards, our AIS features a modular and extensible architecture, allowing for flexible configurations using Load Break Switches (LBS), Vacuum Circuit Breakers (VCB), and fuse combinations. It is the ideal choice for indoor substations, commercial buildings, and industrial facilities where space allows and budget optimization is key.
Core Features & Advantages
Eco-Friendly & SF6-Free: Relies entirely on dry air for insulation. Fully compliant with stringent global environmental regulations, eliminating the need for gas monitoring and specialized disposal.
Visible Isolation for Ultimate Safety: Unlike sealed gas tanks, our AIS is designed with inspection windows. Operators can physically verify the open/closed/earthed status of the switch contacts, providing peace of mind during maintenance.
Highly Cost-Effective (Lower CAPEX): Offers a significantly lower initial investment compared to Gas Insulated Switchgear (GIS). The simplified structure also means readily available spare parts and lower routine maintenance costs.
Modular & Extensible Design: Features a highly flexible architecture. Cabinets can be easily added or replaced on-site to expand the ring network without disrupting the existing infrastructure.
Smart Automation Ready: Fully compatible with distribution automation. Can be equipped with motorized operating mechanisms, Fault Passage Indicators (FPI), and Remote Terminal Units (RTU) for seamless integration into modern SCADA systems.
Technical Specifications
Applicable Standards | IEC 62271-200, IEC 62271-100, IEC 62271-103 |
Rated Voltage | 12kV / 17.5kV / 24kV |
Rated Frequency | 50Hz / 60Hz |
Insulation Medium | Air |
Rated Current (Busbar) | 630A / 1250A |
Rated Current (LBS / VCB) | 630A / 1250A |
Short-time Withstand Current | Up to 25kA for 3s |
Internal Arc Classification (IAC) | IAC A-FL 20kA / 1s (Standard) |
Degree of Protection | IP3X / IP4X (Enclosure) |
Loss of Service Continuity | LSC2A |
Main Applications
• Commercial & Residential Real Estate: Basement substations and electrical rooms where environmental control is maintained.
• Industrial Plants: Manufacturing facilities and mining camps requiring robust, easily maintainable switchboards.
• Compact Secondary Substations (CSS): Easily integrated into packaged substations (kiosks) for urban grid expansion.
• Green Energy Projects: Installations prioritizing zero greenhouse gas emissions and sustainable supply chains.
1. What is an AIS RMU and how does it differ from a GIS RMU?
An Air Insulated Switchgear (AIS) RMU uses atmospheric air as the primary insulation medium between phases. Unlike Gas Insulated Switchgear (GIS), which uses SF6 gas in a sealed tank, AIS offers a visible break during isolation and is generally more cost-effective and easier to maintain without specialized gas-handling equipment.
2. What are the primary applications for Air Insulated Secondary Switchgear?
AIS RMUs are widely used in secondary distribution substations, commercial buildings, shopping malls, and industrial plants. They are the preferred choice for indoor installations where environmental regulations limit the use of SF6 greenhouse gases.
3. What functional units are available in your AIS RMU series?
Our AIS RMU is a modular system that can be configured with:
Load Break Switch (LBS) Unit: For incoming and outgoing cable control.
Fuse-Switch Combination Unit: Specifically designed for transformer protection.
Vacuum Circuit Breaker (VCB) Unit: For high-capacity protection and frequent switching.
Metering Unit: For PT/CT voltage and current measurement.
4. How do you ensure safety during operation and maintenance?
Safety is built into our mechanical design. Every AIS RMU features a strict "Five-Prevention" interlocking system, preventing accidental entry into live compartments and ensuring the earthing switch cannot be closed while the main switch is "ON." The visible isolating gap provides operators with clear visual confirmation of safety.
5. What are the rated voltage and short-circuit parameters for your AIS?
Our standard AIS RMUs support rated voltages of 11kV, 12kV, or 24kV. They feature a rated current up to 630A or 1250A and a rated short-time withstand current (Icw) of 20kA or 25kA for 3 seconds, meeting international IEC standards.
6. Is the AIS RMU extensible for future project growth?
Yes. Our AIS RMUs feature a modular side-extension design. You can easily add extra functional units to an existing lineup using a standard busbar coupling kit, providing excellent flexibility as your facility's power demands grow.
7. What Ingress Protection (IP) rating does the enclosure provide?
Our standard indoor AIS RMU enclosure is rated at IP3X or IP4X. This protects against the entry of tools or wires, ensuring the safety of personnel working near the equipment while maintaining sufficient ventilation for natural air cooling.
8. What materials are used for the cabinet construction in your factory?
We use high-quality Alu-Zinc coated steel (Galvalume) or cold-rolled steel plates with a high-durability electrostatic powder coating. This ensures the frame is rigid, corrosion-resistant, and provides excellent electrical continuity for earthing.
9. Can the AIS RMU be integrated into a smart monitoring system?
Absolutely. We can equip the units with Intelligent Microcomputer Protection Relays and motorized mechanisms. These support communication protocols like Modbus-RTU or IEC 61850, allowing for real-time remote monitoring of load, temperature, and fault status.
10. What documentation is provided for international shipping from Shanxi?
Every export order is accompanied by a complete technical package in English, including:
Single Line Diagrams (SLD) and GA Drawings.
Factory Acceptance Test (FAT) Reports.
Type Test Certificates (covering Temperature Rise and Dielectric tests).
Installation and Commissioning Manuals.
