Failure mode analysis of Hybrid DC Circuit Breaker

Dragan Jovcic* (Corresponding Author), Mohammad Azizian Fard, Mario Zaja

*Corresponding author for this work

Research output: Contribution to conferenceUnpublished paperpeer-review


Hybrid DC circuit breakers are expected to become key components in DC
transmission grids, and several units have already been installed in recent years. This paper studies the response of hybrid DC circuit breakers under the failure of one or several breaker components.
Failures of five key components are considered including: load commutation switch, ultrafast disconnector, main breaker valve, energy absorber and residual current breaker. A failure of each component is analysed while the component is in each of the three states: open, closed and during the opening process. The failure modes are discussed for each component. Surge arrester failure study inside energy absorber is supported with experimental results, and it is concluded that the arresters are normally expected to fail in a short circuit.
The impact of a single or multiple component failure on system-level performance of a hybrid DCCB is assessed on the same three states as for the individual components. It is concluded that in DCCB open state, a single component failure would not change the state of the breaker. On the other hand, a failure of any component in closed state or during the DCCB opening process could lead to system-level failure of the DCCB. The importance of backup protection in DC grids in case of a failed DCCB is highlighted.
Original languageEnglish
Number of pages13
Publication statusPublished - 1 Oct 2019
Event2019 CIGRE SC B4 International Colloquium - Muldersdrift, South Africa
Duration: 1 Oct 20195 Oct 2019


Conference2019 CIGRE SC B4 International Colloquium
Country/TerritorySouth Africa


  • DC grid protection
  • hybrid DC circuit breaker
  • component failure


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