What Are The Types Of High-voltage Switchgear?

High-voltage switchgear is mainly divided into two types: fixed and truck-mounted. It can also be further subdivided according to insulation medium, structural design, and application to meet the needs of different power scenarios.

 

1. Classification by Circuit Breaker Installation Method
This is the most fundamental classification method, directly related to the ease of maintenance and power supply reliability.

Fixed Switchgear: All electrical components (such as circuit breakers) are fixedly installed inside the cabinet. It has a simple structure and low cost, suitable for older power distribution systems with low requirements for power supply continuity. A typical model is GG1A-12(F).

Truck-mounted (Removable) Switchgear: Key components such as circuit breakers are installed on a removable truck, allowing faulty units to be pulled out for maintenance without power interruption, significantly improving operation and maintenance efficiency and power supply reliability. Commonly found in modern high-voltage distribution rooms, such as the KYN28A-12 model.

 

2. Classification by Insulation Medium
The insulation method determines the equipment size, environmental adaptability, and safety.

Air-Insulated Switchgear (AIS): The main conductive circuit is exposed to air, relying on air as the insulating medium. A large electrical clearance is required, therefore the cabinet is relatively wide (typically over 800mm), suitable for general indoor environments.

Gas-Insulated Switchgear (GIS/Gas-Filled Switchgear): High-voltage components are sealed in a gas chamber filled with inert gases such as SF6, providing high insulation strength and significantly reducing size (width can be as low as 500mm), suitable for space-constrained locations such as underground substations and wind turbine towers.

Solid-Insulated Switchgear: Employs a fully sealed solid insulation structure with no exposed live parts, offering excellent dust and moisture resistance, particularly suitable for harsh environments such as coastal areas and mines.

 

3. Classification by Cabinet Structure: Reflects the internal compartment design and safety level.

Metal-Enclosed Armored Type (Type K): Each functional unit is completely isolated by a grounded metal partition, providing high safety, such as the KYN series.

Metal-enclosed partition type (Type J): Similar to armored type, but uses non-metallic partitions, resulting in slightly lower cost.

Metal-enclosed box type (Type X): Fully enclosed, compact structure, such as XGN2-12.

Open type: No protection rating, part of the outer shell is open, now rarely used.