KYN28-12 Armoured Removable AC Metal-Enclosed Switchgear
KYN28-12 (GZS1) is a metal-clad withdrawable AC metal-enclosed switchgear designed for three-phase AC 50Hz power systems with rated voltage up to 12kV. It is used to receive and distribute electrical energy, as well as to control, protect, and monitor power circuits in medium voltage distribution networks.
The switchgear features a compartmentalized metal-clad structure with independent busbar, circuit breaker, cable, and low-voltage compartments, each separated by grounded metal partitions in accordance with IEC 62271-200 internal arc classification standards (IAC AFLR up to 40kA 1s). The newly introduced and developed high-current and high-breaking capacity variant can also be used separately as a high-voltage generator outlet.
Equipped with VD4/VS1/ZN63 series vacuum circuit breakers mounted on a precision wheeled carriage, the KYN28-12 supports three operating positions — Connected, Test, and Disconnected — ensuring maximum operational flexibility and maintenance safety.
Technical Specifications
| Item | Specification |
|---|---|
| Rated Voltage | 3.6kV / 7.2kV / 12kV |
| Rated Insulation Voltage | 12kV |
| Rated Frequency | 50Hz / 60Hz |
| Rated Current (Main Busbar) | Up to 3150A / 4000A (high-current variant) |
| Rated Short-time Withstand Current (Icw) | 25kA / 31.5kA / 40kA (4s) |
| Rated Peak Withstand Current (Ipk) | 63kA / 80kA / 100kA |
| Degree of Protection | IP4X (enclosure) / IP2X (partition) |
| Internal Arc Classification | IAC AFLR up to 40kA 1s |
| Circuit Breaker Type | VD4 / VS1 / ZN63 series vacuum circuit breaker |
| Operating Mechanism | Spring-operated mechanism (manual or motor-charged) |
| Mechanical Endurance | ≥ 30,000 operations (circuit breaker) / ≥ 2,000 operations (hand-car) |
| Electrical Endurance | ≥ 100 times rated short-circuit breaking |
| Busbar Material | High-conductivity electrolytic copper (T2 grade) with silver-plated contacts |
| Hand-car Positions | Connected / Test / Disconnected (3-position) |
| Standards | IEC 62271-200, GB 3906 |
Key Features
- Metal-Clad Compartmentalization: Independent busbar, circuit breaker, cable, and low-voltage compartments with grounded metal partitions prevent internal arc fault propagation and ensure operator safety to IEC 62271-200 standards
- High-Current & High-Breaking Variant: Supports main busbar current up to 4000A and short-circuit withstand up to 40kA for generator outlet and heavy-load applications
- Withdrawable Vacuum Circuit Breaker: VD4/VS1/ZN63 series vacuum circuit breaker mounted on a precision wheeled carriage with Connected/Test/Disconnected positions; smooth roll-out operation for safe inspection and maintenance without panel shutdown
- Arc-Resistant Construction: Type-tested to IAC AFLR 40kA 1s with pressure-relief flaps directing arc gases to safe exhaust areas, ensuring personnel safety during internal arc faults
- Reliable Interlocking System: Comprehensive mechanical and electrical interlocks prevent incorrect operations — including preventing breaker withdrawal when in closed position, and preventing breaker closure when hand-car is in intermediate position
- Compact Footprint: Space-saving design reduces substation floor space requirements by up to 30% compared to fixed-type alternatives of the same rating
- Proven Technology: The most widely used medium voltage switchgear model in China with over two decades of field-proven performance across tens of thousands of installations
Applications
- Thermal and hydro power plants — auxiliary power supply and generator outlet
- 6kV/10kV substations — power receiving and distribution
- Industrial enterprises — motor control and process power distribution
- Commercial and public buildings — main medium voltage switchboards
- Infrastructure — airports, hospitals, data centers, water treatment facilities
- Mining and metallurgy — reliable power supply under harsh conditions