Product Overview
YIMENG Ring Main Unit (RMU) provides switching, isolation and protection for medium-voltage distribution networks. It is suitable for ring-network and radial distribution arrangements serving compact substations, industrial facilities, commercial developments and renewable energy projects.
The product range covers 12 kV, 24 kV and 36 / 40.5 kV classes, with rated current options of 630 A and 1,250 A depending on the selected configuration. Functional units can be combined around incoming supplies, outgoing cables and transformer feeders, while manual or motorized operating mechanisms support different site operating requirements.
Key Features
Compact arrangement for distribution rooms and compact substations
Functional configurations for cable switching and transformer protection
Voltage classes covering 12 kV, 24 kV and 36 / 40.5 kV
Rated current options of 630 A and 1,250 A
Manual or motorized operating mechanisms
Insulation options subject to the selected model
Technical Specifications
| Parameter | Unit | 12 kV Class | 24 kV Class | 36 / 40.5 kV Class |
|---|---|---|---|---|
| Rated voltage | kV | 12 | 24 | 36 / 40.5 |
| Rated frequency | Hz | 50 / 60 | 50 / 60 | 50 / 60 |
| Rated current | A | 630 / 1,250 | 630 / 1,250 | 630 / 1,250 |
| Busbar rated current | A | 630 / 1,250 | 630 / 1,250 | 630 / 1,250 |
| Rated short-time withstand current | kA | 20 / 25 | 20 / 25 | 20 / 25 / 31.5 |
| Rated short-time withstand duration | s | 3 / 4 | 3 / 4 | 3 / 4 |
| Rated peak withstand current | kA | 50 / 63 | 50 / 63 | 50 / 63 / 80 |
| Rated short-circuit breaking current* | kA | 20 / 25 | 20 / 25 | 20 / 25 / 31.5 |
| Power-frequency withstand voltage | kV | 28 / 42 | 50 / 65 | 70 / 95 |
| Lightning impulse withstand voltage | kV | 75 / 95 | 125 | 170 / 185 |
| Insulation medium options** | — | SF₆ / Air / Eco-gas | SF₆ / Air / Eco-gas | SF₆ / Air / Eco-gas |
| Interruption medium options** | — | Vacuum / Gas | Vacuum / Gas | Vacuum / Gas |
| Protection ratings listed*** | — | IP4X / IP67 | IP4X / IP67 | IP4X / IP67 |
| Operating mechanism | — | Manual / Motorized | Manual / Motorized | Manual / Motorized |
| Installation location | — | Indoor | Indoor | Indoor |
| Reference altitude | m | ≤ 1,000 | ≤ 1,000 | ≤ 1,000 |
| Ambient temperature | °C | −25 to +40 | −25 to +40 | −25 to +40 |
Short-circuit breaking ratings apply to the relevant circuit-breaker functional unit, not automatically to load-break switch units.
Insulation and interruption media depend on the selected equipment design. Availability must be confirmed for the required voltage class and functional unit.
The applicable protection rating for the outer enclosure, sealed tank or individual compartment must be confirmed separately. IP67 is not stated as the protection rating of the complete assembly.
The table summarizes the supplied product-range information. Rating combinations, insulation test conditions and applicable IEC 62271 requirements are subject to the approved technical documentation.
Product Advantages
Compact Layout for Space-Constrained Installations
The compact arrangement helps accommodate medium-voltage switching functions within electrical rooms and compact substations. Final panel dimensions, cable-bending space and maintenance clearances are considered together during layout planning.
Functional Units Matched to the Distribution Scheme
Cable switch, switch-fuse and circuit-breaker functions can be specified according to the available product configuration. This allows the RMU arrangement to follow the project’s incoming, outgoing and transformer-feeder requirements.
Transformer Protection to Suit the Application
Transformer feeders can use an appropriate switch-fuse arrangement or a circuit breaker with protection relays, depending on the selected model. The protection method is chosen around transformer ratings, fault levels and coordination with upstream and downstream devices.
Switching and Isolation for Network Operation
Switching, isolation and earthing functions support planned network operation and maintenance. Interlocking arrangements help control the operating sequence, with the final functions confirmed for the selected configuration.
Manual or Motorized Operation
Manual mechanisms suit local operating requirements, while motorized options can support electrical operation. Remote control, status indication and communication interfaces can be reviewed where required by the project.
Enclosed Primary Equipment
For gas-insulated configurations, primary equipment is housed within a sealed tank, reducing direct exposure to the surrounding environment. Inspection and maintenance requirements remain specific to the supplied tank, operating mechanisms, cable connections and protection devices.
Typical Applications
Utility Distribution Networks
Cable switching, sectionalizing and transformer-feeder protection in suitable ring or radial distribution networks.
Compact Substations
Medium-voltage switching and protection within compact substations supplying residential developments, commercial facilities and public infrastructure.
Industrial Parks and Commercial Developments
Distribution to local transformers and feeder circuits, with functional units selected around site loads and operating requirements.
Renewable Energy Projects
Switching and protection for suitable wind and solar distribution circuits, subject to the required voltage class, current ratings and grid-connection design.
Discuss Your RMU Configuration
Send us your single-line diagram, required number of ways or project specifications so we can review a suitable RMU arrangement.
For an initial enquiry, please provide:
- System voltage and rated frequency
- Rated current and prospective short-circuit current
- Required number of ways and function of each way
- Transformer capacity and preferred protection method
- Required short-time withstand duration
- Preferred insulation medium, if specified
- Manual, motorized or remote-control requirements
- Cable sizes, quantities and connection requirements
- Installation space, altitude and ambient conditions
- Required quantity and project specifications
Final functional-unit combinations, dimensions, protection settings and accessories will be confirmed against the project requirements.
Request a Quote
Share your project requirements for configuration review.
