SF₆ - free Medium Voltage in practice: UniSec Air
Proven in real applications
UniSec & UniSec Air
UniSec is an indoor air-insulated switchgear for medium voltage secondary distribution up to 24kV. It offers a broad portfolio of functional units and technical features and is suitable for a wide range of applications including industry, renewable energy plants, distribution and transformer substations, data centers, small generation systems, buildings and infrastructure, and smart grids.
UniSec also offers a sulfur hexafluoride (SF6) free variant called UniSec Air. The new switchgear includes the switch disconnector and disconnector GSec Air. This new component has a dedicated vacuum interrupter for breaking capacity as the insulation medium with a global warming potential (GWP) of zero. The switchgear also contains a vacuum circuit breaker and is fully compliant with IEC standards and the EU F-gas regulation (EU) 2024/573.
UniSec and UniSec Air provide robust control and protection, metering, monitoring, and diagnostics suitable for various applications.
UniSec
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UniSec Air
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UniSec, SF6 Switch disconnector GSec with SF6 gas. ABB’s complete transition to SF6 -free switchgear will be phased in line with our ambitious sustainability targets, evolving regulatory deadlines, market demand, and production capacity. |
UniSec Air, SF6-free Switch disconnector and disconnector GSec Air with dry air and dedicated vacuum interrupter for breaking capacity.
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Product scope
| UniSec | UniSec Air | |
| Max. rated voltage |
up to 24 kV | up to 24 kV |
| Max. rated continuous current (busbar) | up to 1250 A | up to 630 A, up to 1250 A with LSC2B frontal withdrawable circuit breaker panel |
| Max. rated short-time withstand current | up to 25 kA | up to 20 kA, up to 25 A with LSC2B frontal withdrawable circuit breaker panel |
| Insulation medium | Switch disconnector GSec with SF6 gas | Switch disconnector and disconnector GSec Air with dry air |
| Standards | IEC | IEC |
| Other | High duty circuit breakers with M2 (10000 operations) mechanical endurance | High duty circuit breakers with M2 (10000 operations) mechanical endurance |
| Applications | Building and infrastructure, industry and transportation, data centers, distribution and renewables |
Building and infrastructure, industry and transportation, data centers, distribution and renewables |
* ABB’s complete transition to SF6 -free switchgear will be phased in line with our ambitious sustainability targets, evolving regulatory deadlines, market demand, and production capacity
Customer benefits
Flexible and modular design
This flexible design offers ultimate versatility with a wide range of functional units (from circuit breakers to protection relays) suitable for all indoor applications. Its modularity simplifies installation, operation, and maintenance, and full compatibility between UniSec Air and UniSec ensures effortless integration and easy future expansion, supporting a high degree of customization to meet global needs.Safe and Reliable Operation
The system ensures safe and reliable operation through comprehensive mechanical and electrical interlocks, maximizing operator protection. Safety is further enhanced by internal arc classification and tailored gas exhaust configurations. Dedicated Service Continuity Solutions (LSC2B/LSc2A/LSC2) are available to minimize service interruption and guarantee high availability when needed most.Smart Monitoring and Maintenance
Equipped with a comprehensive set of monitoring and diagnostic features, the system provides continuous operational insights to optimize switchgear performance. This smart capability supports a proactive, preventive maintenance strategy, significantly reducing unexpected failures, lowering maintenance costs, and extending the equipment's overall lifespan.Frequently Asked Questions
UniSec Air is an indoor, air‑insulated medium‑voltage switchgear for secondary distribution up to 24 kV.
UniSec Air is used in applications such as substations (utility distribution), large buildings (shopping malls, skyscrapers, resorts), infrastructure (ports, airports, highways, stadiums, hospitals, universities), industry (food and beverage, automotive, semiconductors, pharmaceutical), renewable energy plants, colocation and enterprise data centers and smart grids, where modular and flexible medium‑voltage distribution is required.
UniSec Air includes enhanced user‑experience features, including clearer visual indicators for switch status, improved visibility of earthing contacts and cable connections, easier door handling and simplified front and lateral cable access. These updates support safer operation, easier installation, and more intuitive maintenance while maintaining compatibility with existing UniSec systems.
UniSec Air is the SF₆‑free version of the UniSec switchgear. UniSec Air contains GSec Air, a general-purpose switch disconnector that uses dry air as the insulation medium - with a global warming potential (GWP) of zero - and vacuum interrupter for breaking capacity. GSec Air incapsulate all medium voltage active parts (contacts) thus preventing the external environment from jeopardizing its functionality (free from humidity, dust, pollution). Conventional UniSec uses an SF₆‑insulated switch disconnector. Both systems share the same footprint, modular design and operational concept.
Yes. UniSec Air complies with IEC standards and the EU F‑gas regulation (EU) 2024/573, which addresses restrictions on the use of SF₆ in medium‑voltage switchgear. Its SF₆‑free design supports regulatory and decarbonization objectives in medium‑voltage networks. Though the new EU Regulation allows GWP=1, UniSec Air outperforms reaching GWP=0 and supporting end users to enhance their sustainability report and scope 1 and 3 emissions.
Yes. UniSec Air is backward compatible with existing UniSec installations. It is designed with the same footprint and operating principles as UniSec, enabling extensions and upgrades of installed switchgear without major layout changes or system redesign.