Power supply quench protection system of toroidal field superconducting coil for SST-1

The quench protection (QP) system by high current power supply for superconducting magnet (SCM) has been designed, developed, integrated and tested for Toroidal field (TF) coil of Steady State Superconducting Tokamak (SST-1) machine. This protection system has been designed to protect the TF SCM, which consists of 16 D shaped identical coils connected in series at the highest operating current of 10kA with stored energy of 50MJ. The TF Power Supply (TFPS) is 12 pulse AC to DC converter, which can ramp up the current at 5 A/s and maintains the current as required for SST1 experiment. In event of quench the current needs to brought down as fast as possible and dissipate the stored energy in the dump resistor. The TFPS receives the quench trip signal from magnet quench detection control circuit, which trips the power supply, initiates bypass operation and gives trip signal to DC circuit breaker (DCCB). The QP system has been successfully operated in event of quench during individual coil test and during SST-1 machine operation. This paper describes the design, operation and test results of TFPS QP system during the plasma experimental campaigns of SST-1. (author)