At CRPP in Villigen (Switzerland), the superconducting windings of the EDIPO and SULTAN test facilities need to be protected in case of quench. The detection of a quench, which triggers the protection circuit, is based on the comparison of the voltages on the windings with preset thresholds. Each facility has two quench detection systems, one for the main coils and one for the primary coil of superconducting transformer (TRAFO), which supplies the operating current to the test samples. In the years between 2010 and 2013, a Quench Detection System (QDS) has been developed for EDIPO main coils and for its TRAFO. Afterwards, the 25 years old SULTAN QDS has been updated, for its magnet system and TRAFO, on the basis of the work done before for EDIPO. The four QDS are described and the commissioning of the two EDIPO QDS and the SULTAN-TRAFO QDS is reported. The features of the QDS are discussed, including reliability, sensitivity, and reaction time. The lessons learned can be conveniently extrapolated to other QDS for large coils based on voltage threshold.