**5. Conclusions**

The system proposed in this paper can be an innovative concept to introduce new technology for HVDC circuit breakers and fault current limiters. Imposing an UFTMF with the magnitude of 1 T and the rise time of 1 μSec or less to a modified commercial VI led to a considerable disturbance in charged particles' spatial distribution and consequently to a transient increment in arc voltage. The electric current of VI will be commuted successfully to an appropriate parallel capacitive external circuit, and a zero-crossing in the electric current of VI will be achieved. All of these results were calculated by the

finite element method based simulation of copper vapor plasma in VI while the interaction of plasma and UFTMF was considered.

This concept of current interruption introduces an alternative method for the interruption of electric currents when there is no zero-crossing, or there is a long delay time in reaching the zero-crossing. DC current in the HVDC power network and AC current of generators in the HVAC power etwork are the main cases of these applications. Another application of the proposed system is in the HVAC power network where there is a need to have an immediate current interruption. Fault current limiters are the main examples of this situation.

The main technological issues—provision of UFTMF, feeding circuit, and penetration of UFTMF into contact area of VI—were discussed. This novel method will definitely encounter other technological limitations such as necessary variations in the structure of VI, contact surface treatment for the better high-frequency current interruption, UFTMF positioning, etc. Thus, the presented results of this paper call for future experimental validations.

**Author Contributions:** Conceptualization, E.H. and K.N.; methodology, E.H. and K.N.; software, E.H.; validation, E.H.; formal analysis, E.H.; investigation, E.H. and K.N.; resources, E.H.; writing—original draft preparation, E.H.; writing—review and editing, E.H. and K.N.; visualization, E.H.; supervision, K.N.; funding acquisition, K.N. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding. The Article Processing Charges (APC) was funded by NTNU.

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