Measurement of velocities up to 1.1 km/s and test of a very fast quench inducing system

Applications such as superconducting pulsed power transformers and fault current limiters require high propagation velocities and numerous quench starting points appearing in a short time interval (typically less than a millisecond). A few years ago, Alstom successfully tested a 500-J superconducting pulsed power transformer . In order to better model its quick transition to the normal state, an appropriate computer code was created. This paper presents this quench program and the experiment developed to validate it. The experimental set-up enabled to measure propagation velocities up to 1.1 km/s, which to our knowledge are the highest ever published. Furthermore, we took the opportunity to test a new magnetic quench inducing system. The latter revealed the possibility of inducing a quench in a few tenths of microseconds with an energy consumption at least ten times lower than a classical quench heater.