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Transmission and Distribution systems

800 kV Gas Circuit Breaker
800 kV Gas Circuit Breaker

550 kV Gas Circuit Breaker
550 kV Gas Circuit Breaker


  • Circuit breakers are vital equipment for protecting transmission systems. They cut off current instantly in the event of a system failure due to lightning or other issues./li>
  • With high voltage and high current distribution systems, a Gas Circuit Breaker (GCB) that uses SF6 gas, with three times the insulating ability of air, is applied.
  • This technology releases a circuit of electrodes within compressed gas, extinguishes the generated arc by blowing a stream of supersonic air, and interrupts the current.
  • Hitachi is developing Gas Circuit Breakers (GCB) that work with high currents, with voltages from 100 kV to 550 kV, and accurately support increases in breaking capacity.
  • For a UHV (ultra high voltage) transmission project in the United States, Hitachi delivered more than 40 800 kV GCBs (double break) through its subsidiary Hitachi T&D Solutions, Inc..
  • Hitachi is developing GCBs with high-level simulation technologies in R&D, including analytical elements such as high temperature, high voltage, supersonic flow, and discharge of power.