High Voltage IGCTs for HVDC Converter-Stations

The generalized expansion of HVDC systems for applications such as interconnection between countries and renewable energies is unquestionable. The performances and the efficiency of these links are crucial issues as they can transmit several TWh per year, while they are supposed to remain in operation during decades. With the broader use of modular multilevel converters, a huge quantity of semiconductor devices is used in the converterstations, which may increase assembly complexity. This article deals with the use of devices with higher voltages ratings to keep the number of levels reasonable regarding the design constraints. Focusing on Integrated Gate Commutated Thyristors (IGCTs), this paper shows that 9 kV and 6.5 kV IGCTs exhibit excellent performances compared to 4.5 kV devices and that they would be ideal for future +/-640kV/1 GW symmetric monopole HVDC links.