A 12 kV box-type fixed ring main unit for compact ring-network distribution — the economical alternative to a full metal-clad switchgear lineup.
Where a substation needs to distribute power around a ring rather than feed a single transformer through a dedicated breaker bay, a ring main unit is the standard economic answer. The HXGN-12 covers the terminal and branch positions that make up most distribution ring line-ups.
The HXGN-12 is a box-type fixed AC metal-enclosed switchgear built as a ring main unit. The primary switching element is an SF6 load-break switch (FLN36-12 / FLN48-12 type, or ABB SFG) and transformer circuits use a load-break switch and fuse combination. Units are supplied in standard widths that combine into multi-circuit ring line-ups and branch feeders.
Three-position switching — closed, open and earthed — makes the earthing position visually obvious and gives operators a defined isolation point before work starts. In a ring network the same busbar section appears in several cabinets, so a fault or a planned outage on one section is fed from the other direction. Transformer protection is provided by the fuse inside the combined unit, which removes the need for a separate breaker bay in the common terminal-type installation.
| Parameter | Typical value |
|---|---|
| Rated voltage | 12 kV |
| Rated frequency | 50 Hz |
| Main busbar rated current | 630 A (up to 1250 A on request) |
| Branch busbar rated current | 400 / 630 A |
| Load-break switch type | FLN36-12 / FLN48-12 SF6 load-break switch, or ABB SFG |
| Rated short-circuit making current (peak) | 50 kA |
| Rated short-time withstand current | 20 kA, 2 s |
| Rated peak withstand current | 50 kA |
| Power frequency withstand voltage (1 min) | 42 kV phase-to-phase and to earth, 48 kV across the isolating gap |
| Lightning impulse withstand voltage (peak) | 75 kV phase-to-phase and to earth, 85 kV across the isolating gap |
| Protection class | IP2X to IP3X |
| Operating mechanism | Manual or electric, with optional FTU/RTU automation |
| Ambient temperature | -35 °C to +40 °C |
| Altitude | Up to 1000 m without derating |
| Compliance | GB/T 3906-2020, GB/T 11022-2020, IEC 62271-200 |
Industry reference values for this equipment type. They describe the common rating range of the category and are not XINSHENG ELECTRIC-specific factory figures. Final values are confirmed in the technical agreement and order drawing.
Decide first whether the ring needs a fault-break capability or a fuse-protected transformer branch — that choice determines the unit type. Then count the ring sections: each additional circuit means another cabinet width, and the layout has to allow cable entry from the correct side. Check the site altitude and ambient temperature against the standard condition, and confirm whether distribution automation (FTU/RTU) is required by the utility, because that adds both cabinet space and a communications scope.
HXGN-12 is a fixed, box-type ring main unit built around an SF6 load-break switch, sometimes combined with a fuse for transformer protection. KYN28A-12 is a withdrawable metal-clad cabinet built around a vacuum circuit breaker. The RMU is more compact and cheaper and suits ring distribution; the KYN28A-12 is required where full short-circuit current must be interrupted.
The load-break switch alone cannot. In transformer circuits the fuse inside the combined unit clears the fault. If the incoming position of the ring must interrupt the full short-circuit current, specify the breaker version instead.
The main busbar is rated 630 A as standard, with 1250 A available on request. Branch busbar ratings are typically 400 A or 630 A, and fuse maximum rated current is 125 A for the standard ring main unit configuration.
Yes. The high-voltage unit of a YB12 package substation is normally built from HXGN / XGN15 ring main units, so the same equipment type appears in both outdoor kiosks and indoor ring line-ups.
Yes. Electric operating mechanisms with remote indication and FTU / RTU integration can be specified for feeder automation, fault passage indication and remote control.
GB/T 3906-2020 and GB/T 11022-2020, with IEC 62271-200 as the international reference. Routine factory test reports are supplied with each unit.
10 days for standard configurations and 15 days for customized arrangements, counted from deposit plus confirmed technical agreement plus approved drawing. MOQ is 1 unit.
Send us the rated voltage, rated current or capacity, quantity and destination country, plus any single-line diagram. We reply with a configuration proposal and a quotation — usually within 24 hours of receiving complete technical information.
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