KYN28A-12 Armored Removable AC Metal-Enclosed Switchgear | 12kV Indoor High-Voltage Power Distributi

KYN28A-12 Armored Removable AC Metal-Enclosed Switchgear | 12kV Indoor Withdrawable Switchgear

The KYN28A-12 armored removable AC metal-enclosed switchgear is an advanced indoor metal-clad withdrawable switchgear designed for reliable operation and flexible power distribution. It serves as a complete power distribution device for 3.6–12 kV three-phase AC 50Hz systems with single busbar or single busbar sectional configurations.

This switchgear is widely used in power plants, industrial and mining enterprises, medium-voltage substations, and large motor control systems. It performs essential functions such as power reception, transmission, control, protection, and monitoring, making it an ideal choice for modern electrical networks.

Standard Compliance

The KYN28A-12 switchgear fully meets the international standards IEC 298, GB3906, and IEC 62271-202 for high-voltage switchgear and prefabricated substations. It incorporates comprehensive mechanical and electrical interlocking systems to ensure safe and error-free operation.

Safety Interlock Features

This switchgear is equipped with a five-prevention interlock mechanism to ensure operator safety and system reliability:

- Prevents inserting or withdrawing the circuit breaker under load.
- Prevents incorrect opening or closing of the circuit breaker.
- Prevents circuit breaker closing when the grounding switch is closed.
- Prevents accidental entry into energized compartments.
- Prevents incorrect closing of the grounding switch while energized.

The unit can be configured with VS1 vacuum circuit breakers or ABB VD4 vacuum circuit breakers, offering flexibility and high performance in various power systems.

Environmental and Operating Conditions

a. Ambient temperature: +40°C (max), -10°C (min).
b. Altitude: ≤1000 m.
c. Relative humidity: daily average ≤95%, monthly average ≤90%.
d. Earthquake resistance: ≤8 magnitude.
e. Free from corrosive, combustible gases or steam.
f. Designed for environments with minimal vibration and pollution (Category 1 severity).

Structural Features

The KYN28A-12 switchgear is designed according to the GB3906-91 armored metal-enclosed standard. It consists of two major parts: the cabinet body and the central withdrawable handcart. The cabinet is divided into four isolated compartments with the following protection levels:

- IP4X for the overall enclosure.
- IP2X when internal doors are open.

The switchgear supports multiple connection schemes, including overhead lines and cable connections, allowing various functional configurations. It can be installed, debugged, and maintained from the front side, supporting back-to-back installation or wall-mounted layouts to save floor space and enhance safety.

Key Advantages

✔ Compact armored structure for maximum safety
✔ Withdrawable handcart design for easy maintenance
✔ High mechanical interlocking reliability
✔ Compliance with IEC and GB standards
✔ Optional ABB VD4 or VS1 vacuum circuit breakers
✔ Front-access installation and maintenance
✔ IP4X enclosure protection for enhanced durability

Applications

- Power generation plants and substations
- Industrial and mining enterprises
- Infrastructure and utility distribution systems
- High-voltage motor starting and control
- Secondary power distribution and monitoring

KYN28A-12 armored removable AC metal enclosed switchgear

KYN28A-12 armored removable AC metal enclosed switchgear

The KYN28A-12 armored removable AC metal-enclosed switchgear is designed with a modular internal structure to ensure safety, reliability, and ease of maintenance. Each section of the cabinet plays a critical role in achieving stable performance and user-friendly operation. Below are the key functional components that make up the KYN28A-12 switchgear system.

A. Handcart

The handcart frame is fabricated from high-strength thin steel plates processed by CNC machine tools, then riveted and welded for durability. According to specific applications, the handcart can be configured as a circuit breaker handcart, voltage transformer handcart, isolation handcart, or metering handcart. Handcarts of the same specifications are interchangeable for flexible use.

The handcart operates in three defined positions: isolation position, test position, and working position. Each position features a mechanical positioning device to prevent unintended movement, ensuring that the handcart cannot be operated without releasing the interlock system.

B. Busbar Chamber

The busbar chamber connects the main busbar between adjacent switchgear units. The busbars are fixed using branch busbars and static contact boxes. Flat branch busbars are connected to the main and static contact boxes by bolts, without requiring additional clamps or insulators.

For customized applications, the connecting bolts can be encapsulated with insulation and end caps to enhance safety. When the busbar passes through cabinet partitions, it is secured with a busbar bushing. In the event of an internal arc fault, the chamber design effectively limits arc propagation to adjacent units, ensuring both electrical safety and mechanical strength.

C. Cable Chamber

The cable chamber is designed to accommodate current transformers (CTs), grounding switches, lightning arresters, and power cables. A detachable aluminum bottom plate with slots is provided to facilitate easy on-site cable installation and maintenance. This structure ensures excellent accessibility during field operations and upgrades.

D. Relay Instrument Chamber

The relay instrument chamber houses various relays, instruments, signal indicators, and operating switches. According to user requirements, an additional small busbar compartment can be installed on top of the relay chamber, allowing the installation of up to sixteen control busbars. This configuration offers strong adaptability for monitoring and control systems in complex electrical networks.

E. Pressure Relief Device

Pressure relief devices are installed above the handcart chamber, busbar chamber, and cable chamber. In case of an internal fault arc, the internal air pressure of the cabinet rises rapidly. When the pressure exceeds a safety threshold, the metal relief plate automatically opens, releasing hot gases and pressure upwards. This mechanism protects both the operator and the switchgear from damage, ensuring safe operation under fault conditions.

Lock Device

The middle door of the switchgear is connected to the cabinet body through a lock structure equipped with a lifting mechanism, allowing for easier door operation. When closed, the reinforced connection improves the cabinet’s structural strength, enhancing its resistance to internal arc faults and improving overall reliability and safety.

Performance parameters