The RM6-type gas insulated ring main unit is a widely adopted modular medium voltage switchgear within distribution engineering. The key design feature differentiating it from air-insulated cabinets: all live primary components are encapsulated within a sealed tank filled with SF6 gas.
The gas acts simultaneously as insulating medium and arc quenching medium, isolating energized parts from the external atmosphere. This design drastically reduces routine maintenance workload and extends equipment service life, a critical advantage for unattended outdoor distribution facilities.
This series of compact switchgears adopts standardized modular architecture. In engineering design, users can freely combine incoming, outgoing and transformer feeder units according to single-line diagram requirements.
The cabinet adopts separated compartment layout: SF6 gas tank compartment, front operating mechanism compartment and low voltage auxiliary control compartment are physically divided. Field operators are able to select manual or motorized operating mechanisms on demand during project tender design phase.
All primary live assemblies are installed inside a fully welded stainless steel SF6 gas tank. Continuous seam welding minimizes long-term gas leakage risks. Every tank undergoes strict leak detection and rated pressure filling before factory delivery. After proper commissioning, stable internal working pressure can be sustained over decades under nominal operating conditions.
SF6 dielectric properties guarantee reliable insulation performance even for sites with high humidity, industrial dust contamination or coastal salt spray, conditions which easily lead to insulation faults on open-type air insulated equipment.
The complete cabinet is split into multiple functionally independe b nt compartments: sealed primary gas tank, front mechanical operation compartment, low voltage control compartment and cable termination chamber. Mechanical safety interlocks are configured between compartments to prevent human misoperation.
All routine switching operations, state inspection and visual observation can be implemented from the cabinet front panel. Engineers do not need to disassemble the sealed gas tank during normal inspection, significantly improving operational safety for site maintenance crews.
A robust mechanical interlock system is fitted between load switch, earthing switch and cabinet access panels, following standard medium voltage safety operation protocols. Core interlock logic: the earthing switch can only be closed when the main switching device is fully open; cabinet access doors cannot be unlocked when primary circuits remain energized. Front-mounted observation windows enable technicians to visually confirm switch contact status, avoiding hazards brought by blind operation on site.
Since all energized contacts and insulating elements are enclosed within the sealed gas tank, external pollution cannot erode primary components. Unlike air-type switch cabinets which require periodic contact inspection and insulation cleaning, the primary circuit achieves maintenance-free operation throughout its design lifespan. For power utilities and property developers, this directly reduces long-term operational expenditure on inspection labour and spare part replacement.
Engineering designers can configure 2-way, 3-way, 4-way or multi-loop cabinet combinations, covering incoming feeders, outgoing feeders and transformer protection units. Both manual operation and motorised electric drive mechanisms are available options. Auxiliary contact assemblies, short-circuit fault passage indicators and remote signal monitoring modules can be integrated, matching technical specifications for modern smart distribution grid upgrades.
| Parameter | Specification |
| Rated voltage | 12kV |
| Rated frequency | 50Hz |
| Rated normal current | 630A |
| Rated short-time withstand current | 20kA / 3s |
| SF6 gas nominal filling pressure (at 20℃) | 0.04MPa |
| Insulating & arc extinguishing medium | SF6 gas |
| Operation mode | Manual / Motorized operation optional |
| Gas tank protection grade | IP67 |
| Permissible ambient working temperature | -25℃ ~ +40℃ |
| Standard applicable altitude | ≤1000m above sea level (altitude derating modification available for highland projects) |
| Max relative humidity | 95% (non-condensing) |
| Installation arrangement | Indoor power room or inside outdoor prefabricated box substation |
Note: Customized parameter adjustment is supported according to client tender documentation and project technical specifications. Forward your single-line diagram and technical requirements to our engineering team, and we will confirm the matched configuration and formal quotation.
This RM6-type compact ring main unit is widely selected for municipal urban ring distribution networks. Power authorities deploy this equipment for urban grid reconstruction, new district power supply and distribution network upgrading projects. Its compact footprint helps save land occupation for prefabricated substations and accelerates overall project construction progress.
Shopping centres, office parks and dense residential districts require stable secondary distribution infrastructure. Low noise levels and low maintenance demand make this gas insulated ring main unit well suited for commercial and residential power supply schemes. Units can be arranged within outdoor box substations or indoor dedicated power distribution rooms.
Factories, logistics hubs and industrial zones commonly adopt ring network power supply architecture to improve power supply continuity. Robust cabinet construction adapts to fluctuating temperatures and moderate dust levels inside industrial sites. Multi-combination cabinet arrangements can supply power to multiple production workshops within one industrial park.
Photovoltaic power plants and wind farm booster stations require medium voltage switchgear for grid interconnection. Our RM6-type ring main unit can be equipped with protection and metering modules to satisfy grid connection requirements for new energy projects. It provides reliable circuit switching and fault isolation for distributed renewable power output feeders.
Highway service stations, railway auxiliary power stations, ports and airport auxiliary distribution facilities frequently adopt compact gas insulated switchgear. The anti-pollution sealed structure works reliably inside semi-open and outdoor prefabricated substations along transportation corridors.
As a technical supplier specialising in medium voltage gas insulated switchgear, we provide complete RM6-type ring main units and matching spare assemblies. Every cabinet undergoes full factory testing including gas tightness inspection, dielectric withstand test and repeated mechanical operation verification prior to shipment. We can supply technical datasheets, outline dimension drawings, internal wiring schematics and operation manuals for clients’ engineering review and drawing coordination.
Our power engineering team delivers pre-sales technical consultation, single-line scheme optimisation and remote after-sales operational guidance. For large-volume project orders, on-site technical training can be arranged through mutual negotiation. All products adopt export-grade reinforced packaging, suitable for long-distance sea and land international transport to avoid mechanical damage during transit.
Q: Can we adjust the cabinet configuration to match our single-line diagram?
A: Yes. We support flexible matching of feeder switches, earthing switches and secondary protection modules. Send your project single-line diagram to our engineering team, and we will propose the optimized cabinet layout scheme.
Q: Is regular on-site SF6 gas refilling necessary during operation?
A: Under standard operating conditions, the fully welded gas tank maintains an extremely low leakage rate. Routine gas replenishment is not required within the design service life. Portable SF6 gas detection instruments can be supplied as optional accessories for periodic status inspection.
Q: Can this ring main unit be installed in open air directly?
A: The switchgear itself is recommended to be installed inside a box-type prefabricated substation. We can upgrade external anti-corrosion coating if the equipment will operate in coastal high salt-mist environments.
