12kV withdrawable metal-clad switchgear with a middle-mounted vacuum circuit breaker — the workhorse incoming and outgoing feeder for industrial plants, substations and renewable plants.
The KYN28A-12 is the most widely used 12 kV indoor switchgear type in Chinese industrial, utility and renewable projects. Because the breaker trolley is withdrawable, a single failed breaker can be swapped out on site in a fraction of the time a fixed-type cabinet would need.
KYN28A-12 is the factory designation of a 12 kV AC metal-enclosed switchgear and controlgear assembly built on the middle-mounted (withdrawable) vacuum circuit breaker arrangement. The cabinet is divided into four independently grounded metal compartments — busbar, circuit breaker, cable and LV — so an internal fault in one compartment cannot affect the others.
The breaker trolley sits in the middle of the cabinet and uses spring or permanent-magnet operating mechanisms. Inserting or withdrawing the trolley connects or disconnects the primary and secondary circuits at once, which means a breaker can be serviced without exposing live parts. Protection, measurement and control functions are carried by microprocessor protection relays, CTs and VTs inside the same compartment.
| Parameter | Typical value |
|---|---|
| Rated voltage | 12 kV |
| Rated frequency | 50 Hz / 60 Hz on request |
| Highest working voltage | 12 kV |
| Main busbar rated current | 630 / 1250 / 1600 / 2000 / 2500 / 3150 A |
| Circuit breaker rated current | 630 / 1250 / 2000 / 2500 / 3150 / 4000 A |
| Rated short-circuit breaking current | 20 / 25 / 31.5 / 40 kA |
| Rated short-circuit making current (peak) | 50 / 63 / 80 / 100 kA |
| Rated short-time withstand current | 20 / 25 / 31.5 / 40 kA, 4 s |
| Rated peak withstand current | 50 / 63 / 80 / 100 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 | IP4X enclosure, IP2X with breaker compartment door open |
| Circuit breaker type | VS1 series vacuum circuit breaker, middle-mounted |
| Operating mechanism | Spring-charged or permanent-magnet, manual or electric |
| Busbar arrangement | Single busbar or single busbar with section |
| Ambient temperature | -25 °C to +40 °C (outdoor version on request) |
| Compliance | GB/T 3906-2020, GB/T 11022-2020, DL/T 404-2018, IEC 62271-200 |
Values shown are typical ratings for this product family. Final ratings, dimensions and component selection are confirmed in the technical agreement and the order drawing; routine factory test reports are supplied with each unit.
Start from the short-circuit capacity of your 10 kV network, then match the busbar current to the largest load and reserve room for future extension. A 630 A incoming feeder is normally paired with a 630 kVA transformer, while 1250 A and above serves main distribution and larger transformer incoming panels. Breaker brand should follow the utility or EPC specification, because the protection coordination and the acceptance paperwork are written around that brand. Finally, confirm the cabinet width (800 mm or 1000 mm), the room depth and the operating aisle before the drawing is released for production.
KYN28A-12 is a 12 kV AC metal-enclosed switchgear and controlgear assembly with a withdrawable middle-mounted vacuum circuit breaker. It is used for receiving and distributing power in 10 kV networks — plant substations, commercial primary distribution, renewable plant switchyards and ring networks.
12 kV rated voltage, with a highest working voltage of 12 kV. Units for other voltage classes are covered by the KYN61-40.5 range for 35 kV.
The cabinet is built around the VS1 middle-mounted vacuum circuit breaker as standard. VD4, EV12 and HXV equivalents can be supplied where your specification or the local utility requires a particular brand, provided the dimensional and mechanical interface matches.
A KYN28A-12 is a withdrawable breaker cabinet used for incoming feeders, outgoing feeders and transformer protection in a substation. A ring main unit such as HXGN-12 uses a load-break switch with a fuse and is built for compact ring-network distribution. If you need to interrupt a full short-circuit current, you need a breaker cabinet like KYN28A-12.
Yes. 60 Hz versions are available on request and are reflected in the nameplate, the routine test report and the technical agreement.
GB/T 3906-2020 and GB/T 11022-2020 for AC metal-enclosed switchgear above 1 kV up to 52 kV, with DL/T 404-2018 ordering practice and IEC 62271-200 as the international reference.
The routine factory test report, the approved general arrangement drawing, the equipment nameplate data, the packing list and the operation and maintenance manual are supplied with each shipment.
12 months after commissioning, and 10 days for standard configurations or 15 days for customized drawings — counted from deposit plus confirmed technical agreement plus approved drawing.
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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