High-energy silicon-carbide (SiC) varistors will be used as quench protection and energy extraction for the toroidal field (TF) coils of the Divertor Tokamak Test (DTT) facility, as well as the Frascati Coil Cold Test Facility (FCCTF). As varistors have a nonlinear voltage/current response, which is also temperature dependent, multiphysical modelling is required to determine the maximum coil hot-spot temperature during a quench. This paper presents both electrical and thermal-hydraulic modelling of a coil discharge through the varistors, compared to an equivalent linear resistor array. For a single Toroidal Field Coil (TFC), tested in the FCCTF, the varistors discharge the current approximately 10 s faster than linear resistors, resulting in a reduction of the maximum coil hot-spot temperature of 10 K. In DTT with 18 TF coils and 3 discharge assemblies, varistors reduce the discharge time and maximum coil hot-spot temperature by approximately 20 s and 25 K, respectively.
Multiphysical modelling of superconducting coil discharge through varistors
Lampasi A.;
2025-01-01
Abstract
High-energy silicon-carbide (SiC) varistors will be used as quench protection and energy extraction for the toroidal field (TF) coils of the Divertor Tokamak Test (DTT) facility, as well as the Frascati Coil Cold Test Facility (FCCTF). As varistors have a nonlinear voltage/current response, which is also temperature dependent, multiphysical modelling is required to determine the maximum coil hot-spot temperature during a quench. This paper presents both electrical and thermal-hydraulic modelling of a coil discharge through the varistors, compared to an equivalent linear resistor array. For a single Toroidal Field Coil (TFC), tested in the FCCTF, the varistors discharge the current approximately 10 s faster than linear resistors, resulting in a reduction of the maximum coil hot-spot temperature of 10 K. In DTT with 18 TF coils and 3 discharge assemblies, varistors reduce the discharge time and maximum coil hot-spot temperature by approximately 20 s and 25 K, respectively.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
