What Is Air Insulated Switchgear (AIS)?

Air Insulated Switchgear (AIS) uses air as its insulating medium to control, protect, and distribute electrical energy in medium and high voltage power systems.

With a long track record in substations worldwide, AIS remains one of the most widely adopted switchgear solutions — valued for its straightforward structure, lower initial cost, and ease of maintenance.

How AIS Works

AIS maintains insulation by keeping adequate clearance between energized components. Air — combined with solid insulators — prevents electrical breakdown and arc formation. Its operation covers three core functions:

• Insulation: Air and insulators separate conductive parts to prevent flashover.
• Control: Circuit breakers manage current flow under normal and fault conditions.
• Protection: Faults trigger rapid disconnection to limit damage and restore stability.

Compared with gas-insulated systems, AIS avoids complex sealing structures , simplifying both operation and long-term management.

Main Components of AIS

Air-insulated switchgear consists of several key components that work together to control, protect, isolate, and distribute electrical power. The table below summarizes the main components of AIS and their core functions.

Component	Role	Function
Circuit Breaker	Protection	Interrupts current during normal operation and fault conditions
Disconnect Switch	Isolation	Provides visible isolation during maintenance and switching
Current / Voltage Transformers	Measurement	Measure electrical parameters for monitoring and protection systems
Busbar System	Distribution	Distributes electrical energy across circuits
Surge Arrester	Over Voltage Protection	Limits damage from lightning and overvoltage events
Earthing Switch	Safety Grounding	Grounds equipment during maintenance for personnel safety

AIS Advantages & Limitations at a Glance

Like any electrical solution, AIS has its strengths and some limitations. Understanding both sides helps in selecting the right switchgear for your project.

Typical Applications

• Power transmission substations: Outdoor substations managing voltage levels across regional and national grids.
• Industrial facilities: Steel, mining, and chemical plants requiring continuous and stable power delivery.
• Commercial and public infrastructure: Airports, rail systems, data centers, and large buildings.
• Renewable energy projects: Connecting wind and solar generation to the transmission network.
• Rural and suburban networks: Cost-effective grid expansion where land is available.

Selection Considerations and Trends

Selection Considerations

Selecting AIS is not only about the switchgear itself, but also about site conditions, budget planning, future expansion, and long-term operation. The following flowchart summarizes the main factors that help determine whether AIS is the right solution for a project.

Development Trends

AIS continues to evolve alongside modern power systems, with ongoing improvements enhancing performance, monitoring, and adaptability. Key trends include:

• Integration with digital monitoring technologies
  Sensors and online monitoring systems provide real time data on equipment condition, helping operators detect issues early and plan maintenance more effectively.
• Adoption in digital substations
  AIS is increasingly combined with digital control systems, enabling remote operation, automation, and improved data management across the grid.
• Structural improvements for compactness and safety
  New designs focus on optimizing layout and reducing space requirements while maintaining insulation performance and operational safety.
• Enhanced resistance to environmental conditions
  Advances in materials and coatings improve performance in polluted, coastal, or extreme climate environments, extending equipment lifespan.

These developments expand the application scope of AIS and support its continued role in evolving energy systems.

Our AIS Switchgear Solutions

Wenzhou Naisite Electric Co., Ltd supplies KYN28 air-insulated switchgear designed for medium-voltage distribution in industrial parks, substations, and utility networks. Our AIS solutions combine proven reliability with flexible configuration, supporting projects across a range of voltage levels and site conditions.

For a real project example, you can also view our KYN28 air-insulated switchgear case study for a U.S. project.

Contact us to discuss your project requirements and get a tailored technical recommendation.

Conclusion

Air Insulated Switchgear maintains a strong position in power systems due to its straightforward structure, cost advantages, and reliable long-term performance. It is a practical and proven choice for projects with available space, stable environments, and a focus on total lifecycle value.

As digitalization and sustainability continue to shape the industry, AIS keeps evolving — expanding its application scope and integrating with modern grid management systems.

Not sure which AIS is right for your project?

Our engineering team can review your site conditions and recommend the most suitable solution — at no obligation.

View AIS Product Details →

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