“Armored KYN28 Switchgear” is the common name in the power industry for the KYN28A-12 armored removable AC metal-enclosed switchgear. This type of high-voltage switchgear is designed specifically for indoor power distribution systems. The following is a comprehensive description of its structure, technical features, and application scenarios:
Basic Structure and Components
1. Layered Compartmental Design
Busbar Compartment: Located in the upper portion of the switchgear, it houses the main and branch busbars. Adjacent switchgear sections are separated by bushings, and the busbars are insulated with heat-shrink tubing.
Circuit Breaker Cart Compartment: Located in the central core area, it houses a removable vacuum circuit breaker trolley (such as the VS1 and VD4 models). The trolley features dual “operating/test” positions. When moved, valves automatically open and close to isolate live contacts, allowing for hot replacement.
Cable Compartment: The lower compartment houses current transformers, grounding switches, lightning arresters, and other components. Up to six cables can be connected in parallel. The slits in the floor facilitate construction. Relay and Instrument Room: This independent front compartment houses secondary control components (protective devices, instruments, etc.) and is completely isolated from the high-voltage area.
2. Materials and Protection
- The cabinet is constructed of CNC-machined aluminum-zinc-coated steel with multiple folding processes, providing corrosion and oxidation resistance and high mechanical strength.
The protection level reaches IP4X (IP2X when the cabinet door is open). Each compartment is equipped with a pressure relief duct, which automatically relieves pressure in the event of an internal arc fault to ensure safety.
Key Performance Parameters
Rated Voltage: 3.6-40.5 kV
Applicable to three-phase AC systems
Rated Current: 630A-4000A
Thermal Stability Current: 16-50 kA (4s)
Dynamic Stability Current: 40-125 kA (peak)
Power Frequency Withstand Voltage: 42 kV (1min)
Lightning Surge Withstand Voltage: 75 kV
Operating Power Supply: DC 24-220V / AC 110-220V (compatible with various control circuits)
Protection Level: IP4X (cabinet)
Complies with GB3906 standard
Core Advantages
1. Comprehensive Five-Protection Interlocking System
Strict mechanical interlocking ensures:
The trolley cannot be moved when the circuit breaker is closed;
The trolley cannot be pushed into the working position unless the grounding switch is open;
The grounding switch cannot be closed when energized, eliminating the risk of misoperation.
2. Convenient Operation and Maintenance
The trolley-type circuit breaker can be replaced directly without powering off, minimizing power outages.
Ample cable room space allows for easy access for personnel and maintenance.
3. High-Reliability Design
Independent compartments reduce the risk of fault propagation, and pressure relief ducts prevent internal arcing.
An optional heater can be installed to prevent condensation and is suitable for environments with humidity ≤ 95%.
Typical Application Scenarios
Industries: Power distribution stations, metallurgy, petrochemicals, rail transit, large factories, and urban buildings (such as schools and hospitals).
Functional Role: Serving as the power distribution core of the 10kV distribution network, it handles incoming lines, feeders, and busbar interconnection, providing integrated control, protection, and monitoring.
The armored 28-inch cabinet (KYN28A-12), with its modular compartments, high protection level, and strong short-circuit withstand capability, has become a mainstream medium-voltage power distribution device. It is particularly suitable for industrial scenarios with stringent safety and reliability requirements. Its “five-protection” mechanism and trolley-type design significantly improve operational safety and maintenance efficiency, making it an ideal choice for power distribution in modern substations and large facilities.
Post time: Aug-15-2025
