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 LN2 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 LN2 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 mu s and then interrupted by the LN2 switch within 12 ms. The fast response of SFCL compensates for the long clear time of the LN2 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.