Abstract : This paper presents a fast-blow protection scheme for IGCT semiconductor devices in high-voltage frequency converters. Based on the establishment of a fast-blow model, the impact of the fast-blow protection system on the system under inverter shoot-through faults and the protection effect are analyzed in detail. The results of MATLAB simulation and simplified circuits are compared. The calculation results prove the effectiveness of the proposed simplified protection calculation and demonstrate the correctness of this IGCT protection method. Keywords : high-voltage frequency converter; fast-blow; IGCT; protection 1 Introduction Semiconductor devices such as GTO and IGBT are now widely used in motor frequency conversion drives, power system FACTs devices, etc. IGCT is a new type of high-voltage semiconductor device developed by ABB based on the above devices. Compared with GTO, its switching and loss characteristics are better improved. It is suitable for high-voltage and high-power applications, such as high-voltage frequency converters. Since the integrity of IGCT devices is related to the safe operation of frequency converter equipment, the protection of IGCT is very important. The current protection scheme is to connect two IGCTs in series on the upper and lower DC buses. When an overcurrent is detected, these two IGCTs are used to turn off, thereby protecting the IGCT devices in the inverter main circuit. This protection increases the complexity of control. This paper proposes a scheme to protect IGCT devices by installing fast-acting fuses on the bridge arm of a 6kV/1000kW frequency converter, and analyzes the shoot-through fault of the frequency converter. By simplifying the calculation of the fault current, a suitable fast-acting fuse can be easily selected. Based on the establishment of a fast-acting fuse model, the impact of the fast-acting fuse on the system is analyzed. Comparison of simulation waveforms and simplified calculation results verifies the effectiveness of the simplified calculation. It also shows that the selected fast-acting fuse can protect the IGCT under fault conditions. [b][align=center]For more details, please click: Fast-acting fuse model and IGCT protection in high-voltage frequency converters[/align][/b]