KYN28-12 Armored Removable Switchgear

KYN28-12 Indoor AC metal-enclosed withdrawable switchgear‌ are indoor complete distribution equipment widely used in medium voltage power systems. KYN28-12 Armored Removable Switchgear have the characteristics of safety, reliability, convenient maintenance, and strong intelligent adaptability.

Scope of Application

center-mounted cabinet are suitable for single bus, single bus segmented, and double bus segmented power systems with three-phase AC 50/60Hz and rated voltage 6-12kV. The core application scenarios include:

1. Distribution and control of electrical energy in power plants and substations

2. Distribution systems for metallurgical and chemical industries, rail transit, and industrial and mining enterprises

3. Power transformation and distribution engineering for residential communities and high-rise buildings

4. Start control and line protection of large high-voltage motors

Technical Specifications

Rated voltage: 6-12kV (maximum operating voltage 12kV)

Rated frequency: 50/60Hz

Rated current: Main busbar 630-5000A, commonly used specifications 630-3150A

1-minute power frequency withstand voltage: 42kV phase to phase and ground to ground, 48kV isolation fracture

Lightning impulse withstand voltage: 75kV phase to phase and relative to ground, 85kV isolation fracture

Rated short-circuit breaking current: 25-40kA

Rated short-time withstand current (4s): 25-40kA

Rated peak withstand current: 63-125kA

Protection level: IP4X shell

KYN28-12 Indoor AC Metal-Enclosed Withdrawable switchgear: A Comprehensive Overview

Introduction

The KYN28-12 is a widely used indoor, AC metal-enclosed withdrawable switchgear designed for medium-voltage power distribution systems. It complies with international standards such as IEC 62271-200 and GB 3906, ensuring reliability, safety, and efficiency in electrical networks. This switchgear is suitable for power plants, substations, industrial facilities, and commercial buildings, providing robust performance in voltages up to 12kV.

This article explores the design features, operational principles, technical specifications, advantages, and maintenance requirements of the KYN28-12 switchgear, offering a detailed understanding of its role in modern electrical infrastructure.

1. Design and Construction

The KYN28-12 switchgear adopts a modular, metal-enclosed structure divided into multiple compartments for enhanced safety and functionality:

1.1 Compartmentalization

Circuit Breaker Compartment: Houses the vacuum circuit breaker (VCB), which can be withdrawn or inserted for maintenance without de-energizing adjacent circuits.

Busbar Compartment: Contains the main busbars and is isolated to prevent accidental contact.

Cable Compartment: Located at the rear for incoming/outgoing cable connections.

Relay and Control Compartment: Equipped with protection relays, meters, and control devices.

The compartments are segregated by grounded metal partitions, ensuring arc fault containment and operator safety.

1.2 Withdrawable Mechanism

A key feature of the KYN28-12 is its withdrawable design, allowing the circuit breaker to be moved between three positions:

Connected Position: Fully engaged for normal operation.

Test Position: Disconnected from the main circuit but control wiring remains active for testing.

Disconnected Position: Fully withdrawn for maintenance or replacement.

This mechanism minimizes downtime during servicing.

1.3 Enclosure Material

The switchgear’s enclosure is constructed from high-quality cold-rolled steel with anti-corrosion treatment, ensuring durability in harsh environments.

2. Technical Specifications

The KYN28-12 switchgear meets the following parameters:

Rated Voltage: 12kV

Rated Current: 630A–4000A

Short-Circuit Current: 20kA–50kA

Insulation Level: 42kV power frequency, 75kV lightning impulse

Protection Degree: IP4X for enclosure, IP2X for internal partitions

Additional features include:

Vacuum Circuit Breaker: Maintenance-free, high breaking capacity.

Earthing System: Integrated grounding switches for safety.

Interlocking System: Mechanical and electrical interlocks prevent misoperation.

3. Operational Advantages

3.1 Safety

Arc-Resistant Design: Compartmentalization and reinforced enclosures mitigate arc flash risks.

Interlocks: Prevent incorrect operations like closing the breaker in the disconnected position.

3.2 Reliability

The vacuum interrupters in the VCB ensure long service life and minimal maintenance.

Robust busbar connections reduce overheating risks.

3.3 Flexibility

Modular design allows customization for radial, loop, or dual-bus configurations.

Compatible with digital protection relays for smart grid integration.

3.4 Space Efficiency

Compact dimensions (e.g., 800mm width per panel) save space compared to fixed-type switchgear.

4. Installation and Maintenance

4.1 Installation Requirements

Environment: Indoor, ambient temperature -10°C to +40°C, humidity ≤95%.

Foundation: Level concrete base with cable trenches.

Clearance: Minimum 800mm front/rear for operation and ventilation.

4.2 Routine Maintenance

Visual Inspections: Check for loose connections, corrosion, or dust accumulation.

Functional Tests: Verify interlocks, breaker operation, and relay settings.

Thermal Imaging: Detect abnormal heating in busbars or contacts.

Maintenance intervals depend on operational load but are typically recommended annually.

5. Applications

The KYN28-12 is deployed in diverse sectors:

Utilities: Substations for urban/rural power distribution.

Industries: Steel plants, mines, and oil refineries requiring high reliability.

Renewable Energy: Integration with solar/wind farms for grid connection.

6. Standards and Certifications

The switchgear adheres to:

IEC 62271-200: Medium-voltage switchgear standards.

GB 3906: Chinese standards for metal-enclosed equipment.

ANSI/IEEE: Optional compliance for global projects.

Conclusion

The KYN28-12 indoor AC metal-enclosed withdrawable switchgear is a cornerstone of modern medium-voltage systems, combining safety, reliability, and adaptability. Its advanced design, compliance with international standards, and ease of maintenance make it a preferred choice for engineers worldwide.

For optimal performance, users must follow installation guidelines and conduct regular inspections, ensuring the switchgear operates efficiently throughout its lifespan.

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