Within the Siemens current limiter program a 100 kVA functional model has b
een realized and tested successfully. According to the modular concept of t
he limiter the functional model is assembled of ten switching elements. YBC
O-films with a thickness of 250 nm and a critical current density above 2x1
0(6) A/cm(2) are deposited by thermal coevaporation (TU Munich) on 4" sapph
ire wafers, To support homogeneous switching the superconducting film is co
vered with a 100 nm Au - shunt layer. Good current limiting performance is
achieved: The steady limiting current is below the nominal current, the pea
k fault current increases up to 3 times the nominal current within an actio
n time of one millisecond. The operational recovery time of the limiter, wi
thin which the switching elements return to the superconductive state again
is about 2 s. Following our limiter program the next step will be a model
device with a nominal switching power of 1 MVA.