Superconducting fault current limiters (SFCL)

The current limiting in high temperature superconducting materials is based on fundamental properties of superconductor. These materials go into the normal (metallic) state when the critical current value is exceeded. The emerging resistance of the material is limiting current.

sFCL Characteristics

  • Energy-saving
    Under normal load the device is “invisible” for the grid
  • Very quick
    When the critical current value is exceeded, the HTS tape almost immediately (~ 0.001 s) turns resistive and the current is limited to the project value. The level of the limited current does not depend on the projected value of the fault current.
  • Reliable
    No external signal is needed for sFCL to switch. The current limiting is provided due to fundamental properties of the high temperature superconductor
  • Self-recovering
    The self-recovery of the sFCL appears after switching the device from the faulted loop (typical recovery time is below 30 s)
  • No wearable parts
  • Fire-safe
First superconducting fault current limiter installed in a power station (courtesy of Nexans, used with permission).
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