Test of a DC-HTS Busbar Demonstrator for Power Distribution in Hybrid-Electric Propulsion Systems for Aircraft

In the framework of the German project TELOS (Thermo-Electrically Optimised
Aircraft Propulsion Systems) a high-temperature superconducting 40 MVA DC demonstrator
busbar for hybrid-electric propulsion systems for aircraft has been developed. The design current
for a temperature below 25 K is 13.3 kA and the rated voltage is 3 kV. The 2-pole busbar contains
2 stacks of REBCO coated conductors which are supported by a 3D-printed structure allowing
compensation of thermal length changes of the superconductor. It fits in a cryostat tube with an
inner diameter of 25 mm. A special focus has been put on low-resistive joints that are necessary
to connect single elements of the busbar system. The special layout of the joints allows an
effective current redistribution between the different tapes in a stack. We present results for the
test of the DC busbar demonstrator in liquid nitrogen at 77 K. The design current for this
temperature is 3.3 kA which corresponds to a rated power of 10 MW. We applied currents up to
3.5 kA and measured the I-V characteristics and contact resistances of 90° and 180° joints in a
virgin and in a strained state thus simulating thermal length changes. ... mehrWe also present results of
Lorentz-Force tests with short AC current pulses up to 20 kA to demonstrate the viability of the
design for application with currents up to 13.3 kA