Electromagnetic Analysis of DTT Poloidal Field Coils During an Electrical Transient

The magnetic system of the Divertor Tokamak Test facility (DTT), comprising all the superconducting poloidal coils, is an important part of the machine. It is composed of several parts mutually coupled among them: six Central Solenoid (CS) coils, six Poloidal Field (PF) coils, the passive structures and the plasma. This implies that a current variation in any poloidal coil (CS or PF) can cause a significant current or voltage variation in the others, as well as a change of the plasma current. In particular, during a major plasma disruption, the magnetic flux in the tokamak changes rapidly producing over-voltage and/or over-current in each poloidal coil, and can be at the origin of severe damage to the components. The assessment of the overvoltage occurring in each poloidal coil has been carried out by an electromagnetic analysis in
Ansys
environment, step-by-step. Different initial conditions were considered for electromagnetic analysis and two possible electrical transients were simulated: a Breakdown event and a major plasma disruption. The Finite Element Model (FEM), the concentrated parameters circuit and the simulation results are here described and presented.