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Generator Circuit Breaker
Designed for Power Plants from 700 to 1,500 MW

GE's FKGA8 generator circuit breaker is the ideal solution for large nuclear, coal or hydro power plants. The compact footprint of the single-phase design makes it suitable for new installations or retrofits of existing GCBs. It is equipped with a highly reliable spring-spring-operated mechanism per pole.

The FKGA8 is the first GCB of that class with breaking tests fully compliant with latest IEC/IEEE 62271-37-013 standard. Its main performances are 210 kA short-circuit breaking current, with 30,000 A nominal current with natural cooling and up to 40,000 A nominal current with IPB forced air cooling.

GE Advantage
Key Benefits

Advanced Architecture

Based on more than 40 years experience in providing generator circuits breakers with performances up to 1,500 MW, GE introduces the FKGA8 with well recognized and advanced architecture suitable for large power plants. The circuit breaker's main contacts are in air, separated from the arcing SF6 chamber. These contacts are therefore protected from the hot current breaking SF6 gases including contaminated particles and associated by-products, reducing premature aging of the equipment. Additionally the combination of the circuit-breaker and the disconnector functions avoids energy losses caused by conventional in-line disconnector.

Enhanced Inspection and Maintenance

The architecture of the FKGA8 allows an easy observation of the main contacts throughout the GCB's periodic inspections. The value of having accessibility without dismantling of circuit breaker is enhanced by the fact that contact resistance measurement cannot alone be considered as reliable evidence (as notified by the latest IEC/IEEE 62271-37-013 ) of the contact health. By segregating the main contacts from the interrupting SF6 gas, the new FKGA8 provides also simple access from outside the breaker during a short, normally scheduled power plant shutdown.



1) Circuit breaker with integrated air-disconnector 1a) Main contacts
1b) Arcing contacts
1c) Safety Visual Switch
1a + 1b) = Circuit breaker
1a + 1c) = Disconnector

2) Earthing switch
3) Capacitors
4) Surge arresters
5) Voltage transformers
6) Current transformers

Key Benefits

  • Advanced architecture of circuit breaker reduces premature aging by relocating the main contacts outside of the SF6 environment
  • Combination of circuit breaker and disconnector function minimizes energy losses
  • Reduced SF6 volume of arcing chamber for lower environmental impact
  • Reliable spring-spring-operated mechanism per pole
  • Main contact's inspection and maintenance made easier and less time consuming
  • Compact breaker size both for retrofits and new installations
Generator Circuit Breaker Generator Circuit Breaker


Ratings Units FKGA8
Rated max. voltage kV 33
Short-circuit breaking current kA Up to 210
Ambient air temperature limits °C -20 °C to +40 °C
Busbar temperature limit/Enclosure temperature limit °C
90/70 °C 105/80 °C
Frequency Hz
50 60 50 60
Max. rated nominal current*    
- Indoor with ambient air 40 °C A
30,000 28,500 27,200 24,500
- Outdoor with ambient air 40 °C A
29,000 26,200 26,200 23,300
*Up to 40,000 A with IPB longitudal forced air cooling

  FKGA8 Circuit Breaker FKGA8 Integrated Air-Disconnector MKG Earthing Switch
Rated peak withstand current kApeak 685 685 575
Rated short-time withstand current kA 250 250 210
Rated duration of short-circuit s 3 3 3