Types of Switchgear: AIS, GIS, RMU and More

Switchgear is essential for controlling, protecting and isolating electrical equipment in power transmission and distribution systems. As a manufacturer and solution provider in the power industry, Lugao supplies transformers, switchgear, circuit breakers, disconnectors, lightning arresters, CT/PT/VT and customized OEM/ODM solutions for utility, industrial and infrastructure projects.

What Is Switchgear?

Switchgear refers to a combination of electrical disconnect switches, circuit breakers, fuses, protection relays and control devices. Its main purpose is to keep power systems safe, stable and easy to operate.

Main Functions of Switchgear

• Protection: Automatically disconnects faulty circuits to prevent equipment damage.
• Control: Helps operators start, stop and manage electrical circuits.
• Isolation: Safely separates equipment for inspection, repair or maintenance.
• Reliability: Supports continuous power supply in power plants, substations, factories and commercial buildings.

Common Types of Switchgear

1. AIS: Air Insulated Switchgear

AIS uses air as the main insulation medium. It is widely used in substations and power distribution networks where space is sufficient and easy maintenance is required.

• Cost-effective and easy to inspect
• Suitable for outdoor and indoor applications
• Requires more installation space than GIS

2. GIS: Gas Insulated Switchgear

GIS uses insulating gas to reduce the size of the equipment while maintaining strong insulation performance. It is often selected for urban substations, compact power rooms and environments with limited space.

• Compact structure and high reliability
• Good performance in harsh or polluted environments
• Higher initial investment compared with AIS

3. RMU for Medium Voltage Distribution

A Ring Main Unit is commonly used in secondary distribution networks, especially for urban grids, industrial parks, commercial buildings and renewable energy connections.

• Compact design for space-saving installation
• Supports reliable ring network power supply
• Suitable for medium voltage cable distribution systems

4. High Voltage Applications

High Voltage Switchgear is designed for transmission networks, substations and large-scale power projects where safe switching, fault interruption and system protection are critical.

• Used in power plants and transmission substations
• Works with protection relays and control systems
• Requires strict insulation, testing and safety standards

5. Low Voltage Distribution

Low Voltage Switchgear is applied in factories, buildings, data centers and power distribution rooms to manage final-stage power distribution and equipment protection.

• Suitable for power distribution and motor control
• Helps protect cables, loads and electrical equipment
• Can be customized for different project requirements

How to Choose the Right Switchgear

• Voltage level: Confirm whether the project requires low, medium or high voltage equipment.
• Installation environment: Consider indoor, outdoor, humidity, dust, altitude and pollution conditions.
• Space availability: Choose compact GIS or RMU solutions when installation space is limited.
• Maintenance needs: AIS may be preferred when easy visual inspection and maintenance access are important.
• Project standards: Select equipment according to IEC, GB or other applicable electrical standards.
• Customization: For special grid, industrial or OEM/ODM requirements, work with an experienced manufacturer.

Why Work with Lugao?

Lugao provides power transmission and distribution equipment for global energy projects, combining product manufacturing capability with engineering support. For switchgear projects, Lugao can assist with product selection, technical configuration and customized solutions based on site conditions and application requirements.

Key Advantages

• Experience in transmission and distribution equipment manufacturing
• Product coverage including switchgear, transformers and protection equipment
• OEM/ODM customization for different project specifications
• Support for utility, industrial, infrastructure and renewable energy applications

Conclusion

AIS, GIS, RMU and other switchgear solutions each serve different power distribution needs. Understanding their structure, application and advantages helps project owners choose safer, more reliable and more cost-effective electrical equipment.