**5. Conclusions**

This paper presents a new topology of a fast proactive Hybrid DC Breaker (HDCCB) to isolate the DC faults in Multi-Terminal VSC-HVDC (MT-HVDC) grids in case of fault current interruption, along with lowering the conduction losses and lowering the interruption time. All modes of operation of the proposed topology are studied. Simulation results verify that compared to the conventional DC CB, the proposed topology has lower interruption time, lower on-state switching losses, and higher breaking current capability. Due to the fact that MT-HVDC systems can share the power among the converter stations independently and in both directions, and considering the fast bidirectional fault current interruption, and reclosing and rebreaking capabilities, the proposed HDCCB can improve the overall performance of MT-HVDC systems and increase the reliability of the DC grids.

**Author Contributions:** F.M. was responsible for methodology, collecting resources, data analysis, writing—original draft preparation, and writing—review and editing. G.-A.N. and M.S. were responsible for the supervision, and writing—review and editing.

**Funding:** M. Saif acknowledges the financial support of Natural Sciences and Engineering Research Council (NSERC) of Canada, as well as National Science Foundation of China under gran<sup>t</sup> number 61873144.

**Conflicts of Interest:** The authors declare no conflicts of interest.
