Which Switchgear Is Best for Solar Plants?

For most medium-voltage solar plants, vacuum circuit breaker switchgear is a strong choice for collector systems, transformer connections, and medium-voltage substations. Depending on the project, this may be configured as metal-enclosed switchgear, RMU, or other MV equipment. The best choice depends on voltage, current, short-circuit level, protection requirements, installation environment, space, automation, and grid-connection specifications.

A solar plant does not normally use one type of switchgear throughout the entire electrical system.

A utility-scale PV project can include multiple electrical stages:

PV modules → inverter → transformer → MV collector network → substation → grid connection

Each stage can have different switching and protection requirements.

For EPC contractors and distributors, the better question is therefore:

Which switchgear configuration is best for each part of the solar plant?

What Switchgear Does a Solar Plant Need?

A solar plant may require different switching equipment for:

• Inverter outputs
• Transformer connections
• MV collector feeders
• Collector substations
• Main MV switchboards
• Auxiliary power
• Grid interconnection
• Substation protection

The exact configuration depends on the plant architecture and voltage level.

For many utility-scale projects, medium-voltage switchgear is particularly important because power from multiple inverter-transformer units needs to be collected and connected to the plant substation.

Why Vacuum Switchgear Is a Strong Choice for Solar Plants

Vacuum circuit breaker technology is widely used in medium-voltage power distribution.

For solar applications, a VCB-based switchgear lineup can provide the switching and protection functions required for MV feeders and transformer connections.

Potential advantages include:

• Suitable MV interruption performance
• No SF6 required for arc interruption
• Compatibility with numerical protection relays
• Motorized operating options
• Remote control capability
• Integration with SCADA systems
• Suitable configurations for renewable-energy projects

The exact product must still be selected according to the project’s electrical specifications.

SF6-Free Switchgear for Solar Farms

Environmental requirements are becoming an increasingly important consideration for renewable-energy projects.

Solar developers and EPC contractors may therefore consider SF6-free switchgear instead of conventional SF6-insulated equipment.

Several technologies can be used.

Vacuum Interruption

Vacuum circuit breakers can interrupt current without using SF6 in the interrupter.

Air Insulation

Air can be used as the primary insulation medium in suitable switchgear designs.

Solid Insulation

Solid insulating materials can provide dielectric separation and support compact MV switchgear designs.

For a solar EPC project, the decision should consider the complete product—not simply whether the switchgear is labeled “green.”

Which Switchgear Is Best for Different Parts of a Solar Plant?

There is no single answer for every location in the plant.

The actual selection should be based on the plant’s single-line diagram.

Solar Plant Switchgear: VCB or RMU?

Both can have a role, but they are not interchangeable in every application.

Vacuum Circuit Breaker Switchgear

VCB switchgear is generally appropriate when the project needs comprehensive circuit-breaker-based switching and protection.

Typical applications include:

• MV feeders
• Transformer feeders
• Collector systems
• Main MV switchboards
• Substation distribution

It can also integrate numerical protection and automation functions.

Ring Main Unit

An RMU can be useful where compact distribution equipment is required.

Solar projects may use RMUs around transformer connections or MV distribution points depending on the network architecture.

An RMU can provide combinations of:

• Load-break switching
• Circuit-breaker protection
• Earthing
• Cable connections
• Fault indication

For larger collector systems with multiple feeders and complex protection requirements, a conventional MV switchgear lineup may provide more flexibility.

What Voltage Is Used for Solar Plant Switchgear?

There is no universal solar-plant voltage.

Medium-voltage collector networks can use different voltage levels depending on the plant design, utility requirements, transformer configuration, and grid connection.

Common equipment categories can include:

• 12 kV switchgear
• 24 kV switchgear
• 36 kV switchgear

The equipment voltage should always be selected according to the actual system voltage and insulation requirements.

For example, a project operating on a system around 24 kV requires switchgear with the appropriate rated voltage and insulation level—not simply equipment marketed as “solar switchgear.”

What Are the Most Important Switchgear Ratings for Solar Plants?

When evaluating products, EPC contractors should focus on the technical specification.

Rated Voltage

The switchgear must be suitable for the system’s operating voltage.

Rated Current

Calculate the expected continuous current under the project’s operating conditions.

Consider:

• Normal plant output
• Transformer rating
• Collector feeder loading
• Future expansion

Short-Circuit Rating

The switchgear must be capable of handling the network’s prospective fault level.

Review:

• Short-circuit breaking current
• Short-time withstand current
• Peak withstand current
• Making capability

Insulation Level

The required insulation performance depends on the equipment voltage and installation conditions.

The manufacturer’s ratings should match the project specification.

Protection Is Just as Important as the Switchgear

A solar plant’s electrical protection system must account for the characteristics of inverter-based generation.

Depending on the system design, protection may include:

• Overcurrent protection
• Earth-fault protection
• Transformer protection
• Busbar protection
• Undervoltage protection
• Overvoltage protection
• Frequency protection
• Directional protection

The protection settings should be coordinated with the plant’s transformers, inverters, collector network, and grid requirements.

This is why buying switchgear separately from the protection philosophy can create problems.

The EPC team should define the protection requirements before finalizing the switchgear configuration.

Should Solar Plants Use Outdoor or Indoor Switchgear?

This depends on the project layout.

Indoor Switchgear

Indoor MV switchgear can be suitable for:

• Central substations
• Control buildings
• Equipment rooms
• Protected electrical enclosures

Potential advantages include controlled environmental conditions and easier access.

Outdoor Switchgear

Outdoor equipment can be useful where:

• Space is available
• The substation is outdoors
• Environmental enclosure ratings are appropriate
• Equipment access is required without a building

The local climate is important.

Solar plants may be located in environments with:

• High temperatures
• Dust
• Humidity
• Salt contamination
• Strong sunlight
• Large temperature changes

The switchgear enclosure and environmental specification should therefore be selected accordingly.

What About Smart Switchgear for Solar Plants?

Modern solar plants increasingly use remote monitoring and automation.

A suitable switchgear system can integrate:

• Motorized circuit breakers
• Remote open/close control
• Intelligent protection relays
• Current and voltage sensors
• Fault indicators
• RTU
• SCADA
• Communication networks

For geographically large solar farms, remote operation can be particularly valuable.

Instead of sending technicians to each electrical location for every switching operation, the plant control system can provide centralized visibility and control where the system has been designed and approved for remote operation.

What Should Solar EPC Contractors Look for?

For EPC contractors, procurement should go beyond the basic product name.

1. Confirm the Single-Line Diagram

The switchgear configuration should match the plant’s electrical architecture.

2. Confirm Grid Requirements

The grid operator may specify requirements for:

• Protection
• Metering
• Voltage
• Frequency
• Fault levels
• Grid connection
• Remote control

These requirements should be incorporated into the switchgear specification.

3. Check Applicable Standards

Ask the manufacturer to identify the relevant standards for the specific equipment.

For medium-voltage switchgear, applicable requirements can fall within the IEC 62271 series, depending on equipment type.

4. Review Test Documentation

Request relevant type-test and routine-test documentation as applicable to the equipment and project requirements.

5. Check Cable Interface

Solar collector systems can involve extensive MV cable networks.

Verify:

• Cable size
• Cable termination type
• Number of cable connections
• Cable compartment dimensions
• Earthing arrangements

6. Plan for Future Expansion

Some solar projects are built in stages.

If expansion is possible, consider whether the switchgear can accommodate additional feeders or future equipment.

Does SF6-Free Switchgear Make Sense for Solar Projects?

It can.

Solar power is already associated with reducing reliance on fossil-fuel generation, so some developers also consider the environmental characteristics of the electrical equipment used in the plant.

SF6-free switchgear can eliminate SF6 from the relevant switchgear design.

However, procurement should still consider:

• Electrical performance
• Environmental conditions
• Dimensions
• Cost
• Maintenance
• Applicable regulations
• Project specifications

“SF6-free” should be treated as one selection criterion, not the only one.

How Much Does Solar Plant Switchgear Cost?

There is no reliable single price for solar plant switchgear.

Cost can vary significantly based on:

• Voltage level
• Number of feeders
• Rated current
• Short-circuit rating
• Circuit breaker configuration
• Protection relays
• Automation
• Metering
• Communication
• Enclosure
• Internal arc requirements
• Project quantity
• Testing requirements

A simple RMU and a multi-panel automated MV switchgear lineup can have very different costs.

For EPC procurement, the better approach is to compare a complete technical and commercial package.

A Practical Solar Switchgear Selection Checklist

Before placing an order, confirm:

Electrical

• Rated voltage
• Rated current
• Frequency
• Insulation level
• Short-circuit rating
• Short-time withstand
• Peak withstand

Protection

• Protection relay
• Transformer protection
• Earth-fault protection
• Overcurrent protection
• Metering requirements

Mechanical

• Indoor/outdoor installation
• Enclosure rating
• Cable entry
• Dimensions
• Access clearance
• Environmental conditions

Automation

• Motorized operation
• Remote control
• SCADA
• RTU
• Communication protocol
• Fault indication

Compliance

• Applicable IEC standards
• Type-test documentation
• Routine testing
• Project-specific specifications
• Local grid requirements

Frequently Asked Questions

Which switchgear is best for solar plants?

For many medium-voltage solar plants, vacuum circuit breaker switchgear is a strong option for collector feeders, transformer connections, and substations. The best choice depends on voltage, fault level, protection, environment, automation, and project requirements.

Is SF6-free switchgear suitable for solar farms?

Yes. SF6-free switchgear can be suitable for solar farms when its electrical ratings, insulation system, protection functions, environmental performance, and applicable standards meet the project requirements.

Is VCB better than RMU for a solar plant?

Neither is universally better. VCB switchgear can offer greater flexibility for feeder protection and automation, while RMUs can be useful for compact distribution and transformer connection applications.

What voltage switchgear is used in solar plants?

Solar plants can use different voltage levels depending on the electrical architecture. MV equipment may include 12 kV, 24 kV, or 36 kV classes, among others. The correct rating depends on the project design and grid requirements.

What type of switchgear is used between a solar inverter and transformer?

The arrangement varies by inverter and transformer architecture. Medium-voltage switchgear, circuit breakers, or other switching equipment may be used depending on the system design and protection requirements.

Does a solar farm need medium-voltage switchgear?

Utility-scale solar farms commonly require MV equipment to collect and distribute power between transformers, collector feeders, and the substation. The exact equipment depends on the plant design.

What should an EPC contractor check before buying solar switchgear?

Check the voltage, current, short-circuit rating, insulation level, protection, cable interface, environmental conditions, automation, applicable standards, testing documentation, dimensions, and grid-connection requirements.

Is indoor or outdoor switchgear better for solar plants?

Neither is universally better. Indoor equipment can provide a controlled installation environment, while outdoor equipment can be suitable for outdoor substations. Climate, enclosure design, maintenance access, and site layout should determine the choice.

Can switchgear for solar farms be automated?

Yes. Suitable MV switchgear can incorporate motorized mechanisms, protection relays, sensors, remote control, SCADA, and other automation functions.

Conclusion

Which switchgear is best for solar plants? For many medium-voltage solar projects, vacuum circuit breaker switchgear is a practical choice because it can provide reliable switching and protection while supporting modern automation and protection systems.

But the best solar switchgear is ultimately the one that matches the project’s electrical architecture.

For a solar EPC contractor, the selection should start with the single-line diagram and grid requirements, then move through voltage, current, fault level, protection, cable configuration, environmental conditions, automation, and applicable standards.

Depending on the location within the plant, the appropriate solution may be a VCB switchgear lineup, RMU, SF6-free switchgear, or another MV configuration.

For new solar projects, it is also worth evaluating SF6-free technologies early in procurement. This gives the project team more options while supporting the broader shift toward alternative switchgear technologies.