Electrical and Thermal Performances of IGCT in High Voltage DC Circuit Breaker

Mechanical direct current (dc) circuit breakers (CBs) are often used in high-voltage dc (HVDC) transmission fields, and they can cut off the circuit when a fault occurs. The main switch integrated gate commutated thyristor (IGCT) can transfer the high-frequency oscillating current, which is generated by the main loop. It helps the CB to cut off the circuit with zero current. In this paper, the electrical and thermal performances of IGCT in dc CB under short-circuit conditions are analyzed. A simulation circuit and finite element simulation platforms are built to conduct static and dynamic analyses of IGCT. The results show that the typical output characteristic model may not be applicable under high current oscillation. The current distribution significantly depends on the carrier lifetime distribution. Under the condition of HVDC circuit breaker with high current impulses, the overall temperature variation of IGCT is not obvious, but the local temperature may temporarily exceed 525 °C, and the thermoelectric stress may lead to the degradation of the device.