Converter-breaker protection strategy

A robust DC grid protection strategy at an affordable cost


The converter breaker strategy is a protection solution for multi-terminal DC grid based on low-speed DC circuit breakers. In this non-selective fault clearing strategy the priority is given to the suppression of the fault current by opening all the converter breakers. At the same time the faulty line is discriminated and, in a second phase, isolated by tripping the DC breakers of the faulty line. Thereafter the converter breakers are reclosed and power is restored in 10-20ms. Simulation studies have demonstrated that the time necessary to bring back the power to entire grid is limited to about 100ms.


Available license



  • Less constrained DC breakers requirements
    (i.e. 20kA -15ms – low energy absorption)
  • DC line limiting reactors not required
  • Efficient backups
  • Multivendor
  • Enable easy grid extensibility
  • Reactive power support during fault clearing


  • Multi-terminal DC grid
  • Bipolar & monopolar configuration
  • Cable system


Patent WO2018042126 (A1)

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