Overview
This 12 kV gas insulated ring main unit is designed for medium voltage distribution systems that require a compact structure and high operational safety. The fully enclosed and solid insulated design reduces environmental impact as well as maintenance workload.
The unit can be configured with a vacuum circuit breaker or a load break switch. It is rated at 630 A, with a short-circuit withstand capability of 20 kA or 25 kA, and the operating mechanism offers a mechanical life exceeding 10,000 operations.
A modular design allows flexible configuration and straightforward expansion, so the unit can be extended as the network grows. The product is suitable for indoor installation and is supplied as a fully assembled, factory-tested set.
Key Features
- SF6-free insulation — the gas insulated and solid insulated design avoids SF6 as the insulating medium, which reduces the environmental impact of the equipment.
- 630 A rated current — suitable for the feeder ratings normally used in secondary distribution networks.
- 20 kA or 25 kA short-circuit withstand — the unit can be specified at either withstand level to match the fault level of the network it is connected to.
- Mechanical life over 10,000 operations — the operating mechanism is rated for more than 10,000 mechanical operations, which supports a long service interval.
- Vacuum circuit breaker or load break switch — the switching device is selected according to whether the feeder must only switch load or also break fault current.
- Modular and expandable — the modular arrangement allows flexible configuration at the outset and straightforward extension later.
- Fully enclosed and solid insulated — the enclosed construction keeps the live parts protected and reduces the maintenance workload over the service life.
Technical Specifications
| Rated voltage | 12 kV |
|---|---|
| Rated current | 630 A |
| Short-circuit withstand | 20 kA or 25 kA |
| Mechanical life | Over 10,000 operations |
| Insulation type | Gas insulated, SF6-free, solid insulated |
| Switching device | Vacuum circuit breaker or load break switch |
| Construction | Fully enclosed, modular |
| Installation | Indoor |
| Supply condition | Fully assembled and factory tested |
| Expansion | Modular design allows flexible configuration and expansion |
Applications
- Urban power distribution networks — compact medium voltage feeders in space-restricted city locations.
- Residential areas — distribution for housing complexes and residential developments.
- Small substations — feeder switching and protection where a compact footprint is required.
- Industrial facilities — medium voltage distribution inside manufacturing and processing plants.
- Transportation hubs — power distribution for transit and transport infrastructure.
- Public infrastructure projects — distribution for public buildings and utility installations.
Installation Conditions
- The unit is designed for indoor installation in a distribution room or switchroom.
- The modular arrangement means adjacent units can be coupled to extend the switchboard as the network grows.
- Allow space in front of the unit for cable termination and for operation of the switching device.
- The unit is supplied fully assembled and factory tested, so on-site work is limited to positioning, cable connection and commissioning checks.
How to Select
- Rated voltage and rated current required by the network — the standard rating is 630 A at 12 kV.
- Short-circuit withstand level — 20 kA or 25 kA, according to the fault level of the system.
- Switching device — vacuum circuit breaker or load break switch for each way.
- Number of ways and the modular arrangement required, including provision for future expansion.
- Indoor installation conditions and the required protection rating.
FAQ
What does SF6-free mean for this ring main unit?
It means SF6 is not used as the insulating medium. The unit uses gas insulation combined with solid insulation instead, which reduces the environmental impact of the equipment while keeping the enclosure compact.
What are the rated current and short-circuit withstand of this RMU?
The unit is rated at 630 A, with a short-circuit withstand capability of 20 kA or 25 kA. The withstand level is selected to match the fault level of the network where the unit will be installed.
How long does the operating mechanism last?
The operating mechanism offers a mechanical life exceeding 10,000 operations, which supports long service intervals in normal distribution duty.
Can it be supplied with a vacuum circuit breaker?
Yes. The unit can be configured with either a vacuum circuit breaker or a load break switch. A circuit breaker is normally selected where the feeder must break fault current, while a load break switch suits feeders that only need switching and isolation.
Can the unit be expanded later?
Yes. The modular design allows flexible configuration and easy expansion, so additional ways can be added to the switchboard as the distribution network grows.
How is the unit delivered and installed?
The ring main unit is supplied as a fully assembled and factory-tested set for indoor installation. On-site work is therefore limited to positioning, cable connection and commissioning checks.
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