Applications of A LN2 Switch Combining With the SFCL in the HTS Electrical Propulsion System

The high conduction loss of solid-state circuit breakers blocks the HTS electrical system implementation for future aircraft. An LN
₂
switch marries the low conduction loss with good DC interruption performance in the cryogenic circumstance. It shows a fascinating prospect in the HTS electrical system. However, the possible applications of such a novel switch have never been discussed. This paper proposed two potential strategies for applying the LN
₂
switch into the HTS electrical system. A low voltage experiment is conducted to validate the combination of the SFCL with an LN2 switch. Heat loss is also calculated based on the experimental results. Same level solid-state circuit breakers with cryogenic parameters are set as a fair comparison. A 10 kA prospective short circuit current is limited to 1.4 kA by SFCL within 580 μs and then interrupted by the LN
₂
switch within 12 ms. The fast response of SFCL compensates for the long clear time of the LN
₂
switch. Heat loss of this combination is 1/120 of the heat generated by the same level SSCB in an assumed 2-hour flight. With proper design, such a combination could meet the protection requirements of any specific HTS electrical system. Refrigeration system size and weight can be significantly reduced.