Detailed Explanation of Structural Features and Technical Parameters of KYN28-12 High-Voltage Withdr

KYN28-12 metal-enclosed withdrawable switchgear is one of the most widely used high-voltage complete sets in current 10kV distribution systems. Its "medium-voltage" design mounts the vacuum circuit breaker on a movable truck, combining operational flexibility and high safety. This article provides a comprehensive interpretation from structural features, technical parameters to application scenarios.

I. Model Meaning and Positioning

In the designation KYN28-12: K stands for metal-enclosed, Y for withdrawable, N for indoor type, 28 for design serial number, and 12 for rated voltage of 12kV. The product complies with the national standard GB 3906 "3.6kV~40.5kV AC metal-enclosed switchgear and controlgear".

II. Cabinet Structural Design

The cabinet is made of aluminum-zinc coated steel plates, processed by CNC machining and multiple folding, then assembled with bolts. It has the following four independent compartments:

• Circuit breaker compartment (truck compartment): medium-voltage truck structure, the circuit breaker can be completely withdrawn from the cabinet for maintenance, and trucks of the same model are interchangeable.
• Busbar compartment: main busbars are arranged horizontally and connected to each cabinet through wall bushings.
• Cable compartment: used for cable connection and current transformer installation, with ample space for easy construction.
• Relay and instrument compartment: houses secondary control and protection devices, completely isolated from the primary circuit.

Each compartment is independently separated by metal partitions. The protection degree reaches IP4X (when cabinet doors are closed), and IP2X between compartments, effectively preventing arc fault propagation.

III. Five-Prevention Interlocking Mechanism

KYN28 is equipped with a complete mandatory "five-prevention" mechanical interlocking function:

• Prevent incorrect opening or closing of the circuit breaker
• Prevent pulling or pushing the truck under load
• Prevent closing the earthing switch when the circuit is live
• Prevent energizing the circuit with the earthing switch closed (or earthing wire connected)
• Prevent entering live compartments by mistake

An insulating shutter partition is provided between the truck compartment and the cable compartment. The shutter structure automatically isolates live contacts to ensure maintenance safety.

IV. Key Technical Parameters

V. Applicable Scenarios

• Power plant outgoing lines and distribution systems
• Distribution centers of large industrial and mining enterprises
• Incoming and outgoing power supply of secondary substations in power systems
• Start-up control of large high-voltage motors
• Distribution sites requiring frequent operations and intelligent monitoring

With its comprehensive advantages of reliable structure, convenient maintenance, and complete safety protection, KYN28 medium-voltage switchgear has become the preferred cabinet type for 10kV distribution projects.