Switchgear for Airport: Selection, Design & Safety Guide

Airports depend on electrical power for far more than passenger terminals and lighting. Runways, taxiways, airfield lighting, navigation-related systems, baggage handling, security systems, communications, radar and surveillance equipment, HVAC, elevators, escalators, fire protection, data centers, parking facilities, and airport operations can all rely on a stable electrical supply.

This makes switchgear for airport applications a critical part of airport electrical infrastructure. The switchgear must provide safe switching, fault protection, isolation, and distribution while supporting the operational requirements of systems that may have very different levels of electrical criticality.

Airport electrical systems also need to accommodate emergency power sources, standby generators, UPS systems, multiple transformers, and potentially redundant distribution paths.

This guide explains how to approach the selection and design of switchgear for airports, including MV and LV systems, critical loads, protection, emergency power, maintenance, and digital monitoring.

What Is Switchgear for an Airport?

Switchgear for airport applications refers to equipment used to control, protect, isolate, and distribute electrical power throughout airport facilities and infrastructure.

Depending on the airport’s size and electrical architecture, the system may include:

• Medium-voltage switchgear
• Low-voltage switchboards
• Circuit breakers
• Load switches
• Disconnectors and isolators
• Earthing switches
• Busbars
• Current transformers and voltage transformers
• Protection relays
• Automatic transfer equipment
• Generator switchboards
• UPS interfaces
• Metering and monitoring equipment

The exact configuration depends on the airport’s utility connection, electrical demand, critical-load requirements, emergency-power strategy, local regulations, and applicable standards.

Why Switchgear Is Critical in Airport Electrical Systems

An airport can contain a combination of commercial, transportation, safety, security, and operational loads.

A temporary interruption to a non-critical administrative area may have limited operational consequences. An interruption affecting airfield lighting, critical communications, security systems, or other essential infrastructure can be considerably more significant.

For this reason, airport electrical designs generally distinguish between different categories of loads and provide suitable distribution and backup arrangements.

Typical airport loads can include:

• Terminal lighting
• Airfield and runway lighting
• Baggage handling systems
• Passenger boarding equipment
• Security systems
• Access-control systems
• Communication systems
• Navigation-related equipment
• Surveillance systems
• Fire alarm and fire protection systems
• HVAC systems
• Escalators and elevators
• Water and drainage pumps
• Parking and transportation systems
• Data and IT infrastructure
• Commercial and retail facilities

Switchgear forms part of the infrastructure that allows these loads to be supplied, protected, isolated, and restored appropriately.

Airport Electrical Power Distribution Architecture

A simplified airport electrical distribution system may follow this structure:

Utility Grid → MV Switchgear → Transformer → Main LV Switchboard → Distribution Boards → Airport Loads

A larger airport may use multiple incoming feeders, substations, transformers, bus sections, emergency generators, UPS systems, and independent distribution paths.

A conceptual architecture could include:

Utility Supply A
↓
MV Switchgear
↓
Transformer A
↓
LV Main Switchboard A

and a second supply:

Utility Supply B
↓
MV Switchgear
↓
Transformer B
↓
LV Main Switchboard B

Emergency sources can be integrated through appropriate transfer and distribution equipment:

Emergency Generator / UPS
↓
Transfer Equipment
↓
Essential Distribution
↓
Critical Airport Loads

The actual architecture should be determined through electrical system studies and the airport’s operational, safety, regulatory, and availability requirements.

Critical and Non-Critical Airport Loads

Not every airport load requires the same level of power continuity.

Critical Airport Loads

Depending on the airport and applicable requirements, critical or essential systems may include:

• Airfield lighting
• Selected navigation-related systems
• Critical communication systems
• Security systems
• Surveillance infrastructure
• Emergency systems
• Fire and life-safety equipment
• Critical control and monitoring systems
• Selected IT and data infrastructure

General or Non-Critical Loads

Other loads may include:

• Offices
• Retail areas
• Restaurants
• General-purpose HVAC
• Parking facilities
• Administrative equipment
• Non-essential lighting

The exact classification depends on the airport’s operational requirements and governing regulations.

This classification is important because it influences the switchgear arrangement, emergency-power connections, redundancy, protection strategy, and distribution topology.

MV Switchgear for Airports

Medium-voltage switchgear may be installed at airport substations or at the utility interface where the incoming supply is at MV.

Common technologies include:

• Air-insulated switchgear (AIS)
• Gas-insulated switchgear (GIS)
• Solid-insulated switchgear
• Fixed circuit-breaker switchgear
• Withdrawable circuit-breaker switchgear
• Ring-main-type equipment for suitable distribution arrangements

Vacuum circuit breakers are commonly used in MV switching and protection applications.

When selecting MV switchgear for airport projects, engineers should consider:

• Rated voltage
• Continuous current
• Short-circuit withstand capability
• Short-circuit breaking capability
• Insulation requirements
• Busbar arrangement
• Incoming and outgoing feeder requirements
• Transformer connections
• Protection scheme
• Cable termination
• Indoor or outdoor installation
• Environmental conditions
• Maintenance requirements
• Future expansion

The airport’s electrical topology should be established before final equipment ratings are selected.

LV Switchgear for Airports

Low-voltage switchgear distributes electrical power downstream of transformers to terminals, airfield infrastructure, buildings, equipment, and other loads.

Airport LV equipment may include:

• Main LV switchboards
• Essential-power switchboards
• Generator switchboards
• Automatic transfer equipment
• Motor control centers
• Distribution boards
• Power-factor correction equipment where appropriate

Circuit breakers can include:

• Air circuit breakers (ACBs)
• Molded-case circuit breakers (MCCBs)
• Miniature circuit breakers (MCBs) at suitable downstream distribution levels

Main LV switchboards should be selected based on load current, prospective fault current, busbar capacity, protection requirements, cable arrangements, operating environment, maintenance access, and expansion needs.

Key Factors When Selecting Switchgear for Airport Applications

1. Rated Voltage

The switchgear must match the electrical system’s nominal and maximum operating voltage.

MV systems can operate at project-specific levels such as 6.6 kV, 10 kV, 11 kV, 12 kV, 20 kV, 22 kV, 24 kV, or 33 kV.

These are examples rather than universal airport voltage levels. The actual rating must follow the local utility network and project design.

2. Continuous Current

Switchgear must be capable of carrying the required continuous current under the specified operating conditions.

The calculation should consider:

• Connected load
• Maximum demand
• Load diversity
• Motor loads
• Transformer ratings
• Emergency operating conditions
• Future expansion

3. Short-Circuit Capability

Short-circuit calculations are essential when selecting airport switchgear.

The study may need to consider:

• Utility fault contribution
• Transformer impedance
• Generator contribution
• Motor contribution where relevant
• Parallel sources
• Bus couplers
• Different operating configurations

The switchgear’s withstand and interruption capabilities must be appropriate for the calculated fault levels at its installation point.

4. Protection Coordination

Protection coordination helps limit the portion of the airport electrical network affected by a fault.

Protection studies may evaluate:

• Overcurrent protection
• Short-circuit protection
• Earth-fault protection
• Transformer protection
• Generator protection
• Selective coordination
• Breaker settings
• Time-current characteristics

The objective is generally to isolate a fault as close as practical to its source while keeping unaffected sections energized.

Airport Emergency and Backup Power

Emergency and standby power are important parts of many airport electrical systems.

Potential backup sources include:

• Diesel or gas generators
• UPS systems
• Battery energy systems
• Separate utility feeders
• Other approved emergency sources

These sources may support designated essential loads when the normal supply is unavailable.

For example, an emergency generator can supply an essential switchboard through appropriately designed transfer equipment. A UPS may support selected sensitive electronic systems where uninterrupted or conditioned power is required.

The generator, transfer equipment, switchgear, UPS, and downstream loads should be engineered as one coordinated electrical system.

Redundancy and Reliability

Large airports may require electrical architectures capable of supporting continued operation during selected equipment failures or maintenance activities.

Potential design strategies include:

• Multiple utility feeders
• Multiple substations
• Multiple transformers
• Split-bus arrangements
• Bus couplers
• Separate essential distribution systems
• Redundant generators
• UPS-backed systems
• Independent distribution paths

Redundancy should be based on the airport’s operational requirements and applicable regulations.

It is also important to consider common-mode failures. Two supposedly independent systems may still share cables, switchboards, rooms, controls, or other infrastructure that creates a common point of failure.

Protection and Selective Coordination

Airport electrical systems can contain large numbers of interconnected loads.

A fault in one distribution branch should not automatically result in unnecessary shutdown of an entire terminal or critical airport facility.

Protection coordination therefore needs to consider the relationship between:

Utility → MV switchgear → Transformer → LV main breaker → Distribution breaker → Final circuit

Protection settings should be studied across different operating configurations, especially when the airport can operate with generators, multiple utility sources, bus couplers, or other alternative supply arrangements.

Protection coordination should be verified using the applicable engineering studies rather than relying solely on default breaker settings.

Environmental Considerations for Airport Switchgear

Airport switchgear may be installed in:

• Electrical substations
• Terminal buildings
• Utility buildings
• Plant rooms
• Baggage facilities
• Airfield electrical facilities
• Outdoor substations

Environmental conditions can vary significantly between these locations.

Designers should consider:

• Ambient temperature
• Humidity
• Condensation
• Dust
• Water ingress
• Corrosion
• Salt exposure near coastal airports
• Altitude
• Ventilation
• Solar radiation for outdoor equipment
• Mechanical vibration where applicable

Outdoor installations require appropriate equipment enclosures and environmental ratings. Indoor installations still require adequate ventilation, temperature control, access, and condensation management.

Digital Monitoring and Airport Power Management

Modern switchgear can incorporate digital protection, metering, communication, and monitoring functions.

Depending on the selected equipment, operators may be able to monitor:

• Voltage
• Current
• Active and reactive power
• Energy consumption
• Power factor
• Breaker position
• Protection alarms
• Fault events
• Equipment status
• Communication status

This information can support airport facility management and electrical troubleshooting.

Digital monitoring can also help operators understand load patterns and identify abnormal operating conditions.

However, monitoring should complement rather than replace physical inspection, testing, preventive maintenance, and safe operating procedures.

Where switchgear is connected to airport control networks or building management systems, cybersecurity, network segmentation, access control, and secure communication should also be considered.

Switchgear Technology Options for Airports

Air-Insulated Switchgear

AIS is a conventional switchgear technology that can be suitable where sufficient installation space is available.

Its selection depends on voltage, fault level, environmental conditions, maintenance philosophy, room dimensions, and other project requirements.

Gas-Insulated Switchgear

GIS can provide a compact arrangement and may be considered where electrical-room space is constrained.

The selected insulation technology and applicable environmental requirements should be evaluated during procurement.

Solid-Insulated Switchgear

Solid-insulated switchgear uses solid dielectric materials as part of the insulation system.

It can be considered for projects where compact construction and alternative insulation arrangements are desirable.

For additional technical background, see this guide to solid-insulated switchgear.

Fixed and Withdrawable Switchgear

Fixed switchgear can provide a straightforward equipment arrangement, while withdrawable switchgear can offer operational and maintenance flexibility in suitable applications.

For withdrawable equipment, the electrical room must provide sufficient space for safe movement, isolation, inspection, and maintenance.

More information is available in this guide to withdrawable chassis for vacuum circuit breakers.

Airport Switchgear Safety

Electrical safety is fundamental to airport power infrastructure.

Important design and operational considerations include:

• Safe isolation
• Earthing
• Electrical and mechanical interlocking
• Protection against accidental contact
• Appropriate equipment labeling
• Controlled access
• Safe cable termination
• Maintenance access
• Arc-flash assessment where applicable
• Documented switching procedures
• Lockout/tagout procedures where required

Because airport facilities can remain operational around the clock, maintenance procedures should be developed with the operational consequences of equipment isolation in mind.

Testing and Commissioning

Testing should verify that the installed switchgear performs according to the approved design and applicable requirements.

Depending on the equipment and project, testing may include:

• Visual and mechanical inspection
• Wiring verification
• Insulation-related tests as applicable
• Circuit breaker functional testing
• Protection relay testing
• Interlock verification
• Control circuit testing
• Metering verification
• Communication testing
• Functional testing of transfer systems
• Site acceptance and commissioning activities

Factory acceptance testing (FAT) can be used to verify applicable equipment functions before shipment. Site testing then verifies installation and system integration.

The exact test program should follow the applicable standards, manufacturer instructions, and project specification.

Common Mistakes When Selecting Switchgear for Airports

Mistake 1: Selecting Equipment Only by Voltage

A correct voltage rating does not guarantee suitability. Current, fault level, insulation, protection, environment, switching duty, and installation conditions must also be evaluated.

Mistake 2: Ignoring Critical Airport Loads

Airfield lighting, communications, security, fire protection, and other essential systems may have different continuity requirements from general building loads.

Mistake 3: Treating Backup Power as an Independent System

Generators and UPS systems must coordinate with transfer equipment, switchgear, protection, and downstream distribution.

Mistake 4: Failing to Study Multiple Operating Modes

An airport may operate under normal utility conditions, generator operation, maintenance configurations, or alternate feeder arrangements.

Protection and load-flow studies should consider relevant operating states.

Mistake 5: Underestimating Maintenance Space

Switchgear dimensions alone do not define the required room footprint.

Engineers should consider front and rear access where required, cable work, breaker withdrawal, inspection, ventilation, and equipment replacement.

Mistake 6: Ignoring Future Expansion

Airport infrastructure can be expanded or modified over time.

Where practical, the design can consider spare feeder positions, additional transformer capacity, busbar capacity, room space, and cable routes.

Mistake 7: Overlooking Environmental Conditions

Outdoor airport installations can experience rain, humidity, dust, corrosion, temperature variation, and other environmental stresses.

The equipment enclosure and environmental design should match the actual installation conditions.

Airport Switchgear Selection Checklist

Before purchasing switchgear for airport applications, review:

• System voltage

• Maximum continuous current

• Short-circuit level

• Transformer ratings

• Utility supply arrangement

• Critical-load classification

• Emergency-power requirements

• Generator interfaces

• UPS requirements

• Transfer equipment

• Protection coordination

• Busbar configuration

• Circuit breaker technology

• Indoor/outdoor installation

• Environmental conditions

• Cable termination

• Maintenance access

• Interlocking

• Monitoring and communication

• Cybersecurity considerations

• Applicable standards

• Factory testing

• Site commissioning

• Future expansion

Frequently Asked Questions

What type of switchgear is used in airports?

Airports can use MV and LV switchgear, including air-insulated, gas-insulated, solid-insulated, fixed, and withdrawable configurations. The appropriate technology depends on voltage, fault level, space, environment, maintenance requirements, and the airport’s electrical architecture.

Why is switchgear important for airports?

Switchgear provides electrical switching, protection, isolation, and distribution. Properly designed equipment helps isolate electrical faults and supports controlled distribution to airport facilities and critical infrastructure.

Is MV switchgear required at every airport?

Not necessarily. The requirement depends on the airport’s utility connection, electrical demand, transformer arrangement, and local distribution system.

What circuit breakers are commonly used in airport MV systems?

Vacuum circuit breakers are commonly used in MV applications. The appropriate breaker rating and configuration depend on the system voltage, current, fault level, switching duty, and protection scheme.

How does emergency power connect to airport switchgear?

Emergency generators, UPS systems, or other backup sources can be connected through appropriately designed transfer and distribution equipment to supply designated essential loads.

Should airport switchgear have redundant power sources?

The required level of redundancy depends on airport operations, applicable regulations, risk assessments, and the electrical system architecture. Multiple feeders, transformers, substations, generators, or distribution paths may be used where required.

Can airport switchgear be installed outdoors?

Yes, where the equipment is specifically designed and rated for the environmental conditions of the installation. Temperature, humidity, rain, dust, corrosion, solar radiation, and other conditions should be considered.

Is digital monitoring useful for airport switchgear?

Digital monitoring can provide information about electrical measurements, breaker status, alarms, and events. It can improve system visibility, but it does not replace physical inspection and maintenance.

What standards apply to airport switchgear?

The applicable standards depend on the equipment and project. IEC 62271 is relevant to many MV and HV switchgear applications, while IEC 61439 applies to many LV switchgear and controlgear assemblies. Airport-specific, electrical installation, safety, and local regulatory requirements may also apply.

What should be considered when selecting MV switchgear for an airport?

Key factors include rated voltage, continuous current, short-circuit capability, insulation, circuit breaker technology, busbar configuration, protection, cable termination, installation environment, maintenance requirements, monitoring, and future expansion.

How can airport electrical faults be isolated?

Protection relays and circuit breakers can detect and interrupt faults within their designed protection zones. Proper protection coordination helps limit unnecessary disconnection of upstream equipment and unaffected loads.

What is the difference between airport normal and emergency power?

Normal power generally comes from the utility supply, while emergency or standby sources such as generators and UPS systems provide power to designated loads when the normal source is unavailable or unsuitable.

Conclusion

Selecting switchgear for airport applications requires more than matching equipment to voltage and current ratings. Airport electrical infrastructure can contain a mixture of critical operational systems, safety-related loads, passenger facilities, commercial loads, and building services, each with different power requirements.

A well-engineered switchgear system should consider the complete electrical architecture, including MV and LV distribution, transformers, circuit breakers, protection coordination, emergency power, redundancy, environmental conditions, maintenance access, digital monitoring, testing, and future expansion.

For airport projects, switchgear should therefore be selected as part of an integrated power-distribution strategy. The final configuration should be based on project-specific electrical studies, applicable standards, local regulations, manufacturer requirements, and the operational needs of the airport.