A New Thyristor-Based Power Electronic Device for DC Circuit Breakers in Medium-Voltage Applications

In this paper, a power electronic device based on gate turn-off thyristors is introduced. The Diode-Assisted Gate-Commutated Thyristor (DAGCT) is designed and optimised for hybrid DC circuit breaker applications employing a fast mechanical circuit breaker. The main topology and operation of the device are analyzed. A press-pack package with a large thermal capacity is developed and the device was successfully simulated for turn-off of a fault current of 3 kA within 1.5 µs, Higher interruption currents could be reached, whereas thermal limits of the components used and maximum fall and rise time of the device current should be considered. A proof-of-concept test is illustrated.