High sensitive quench detection method using an integrated test wire

We have designed a high sensitive quench detection method which works even in the presence of an external perturbing magnetic field. In this method the quench signal is obtained from the difference in voltages at the superconducting winding terminals and at the terminals at a secondary winding strongly coupled to the primary one. The secondary winding could consist in a "zero-current strand" of the superconducting cable no connected to one of the winding terminals or in an integrated normal test wire running along inside the superconducting cable. In this paper, after a short theoretical survey, we present and discuss experimental results on quench detection obtained by this method in comparison with results obtained by the classical middle-point method. It is shown that the integrated test wire method leads to the most efficient and sensitive quench detection especially in the presence of an external perturbing magnetic field.