KYN28A-12 Metal-Clad Withdrawable AC Switchgear

KYN28A-12 is a 12 kV metal-clad, withdrawable AC switchgear widely adopted in medium-voltage distribution networks across utilities, industrial plants, commercial buildings, and renewable-energy installations. It is designed around a center-mounted vacuum circuit breaker (types VS1/ZN63A, VD4, HVX, or EV12s) that rides on a wheeled truck for smooth isolation and withdrawal, enabling safe maintenance without de-energizing the entire bus.

The enclosure is fabricated from high-strength aluminum-zinc coated steel sheets, folded into a monocoque structure that resists distortion under internal arc pressure. Compartments for the breaker, busbars, cables, and low-voltage auxiliary are separated by earthed metal partitions, each with pressure-relief flaps that channel arc gases upward and away from the operator. Complete five-prevention interlocks — preventing incorrect breaker movement, earthing switch operation, and access to live compartments — are built into the mechanical linkage.

Rated parameters: 12 kV nominal voltage, 630 A / 1250 A / 2000 A / 3150 A busbar current, up to 40 kA short-circuit withstand for 4 s. The switchgear is type-tested for internal arc classification (IAC) under IEC 62271-200, with an arc fault classification of AFLR up to 40 kA 1 s.

Applications include main receiving substations for industrial parks, distribution substations in mining and building-materials plants, MV switchboards for data centers, and step-down substations for wind and solar farms. The design allows top-entry or bottom-entry cable termination and supports both single-busbar and double-busbar configurations.

Conforms to GB 3906, GB/T 11022, DL/T 404, IEC 62271-1, and IEC 62271-200. The switchgear is delivered with FAT records, schematic diagrams, instruction manuals, and export packing suitable for sea and air freight.