Error estimation in the Tcs measurement of TF conductors in the SULTAN facility

The main parameter measured in the tests of the TF conductors for the ITER machine is the current sharing temperature. In the voltmetric assessment of Tcs, the voltages are measured on the conductor jacket, due to the technical difficulties to introduce voltage taps inside the stainless steel conduit. The average voltages measured on the jacket do not exactly correspond to those that arise along the single strands, as shown by the presence of early voltages arising during the current ramp up, when the cable is still in the superconducting phase. It is therefore not trivial to evaluate the difference between the cable and jacket voltages, that gives rise to an experimental error in the measurement of Tcs. This paper reports the results of a vast simulation campaign performed with a detailed electromagnetic model of the Cable in Conduit Conductor, in which the origin and the extent of these differences have been investigated, giving an estimate for the experimental error. The impact on measurements of other sources of error such as the signal/noise ratio and the error in the temperature measurements is also reported.