Advances in high voltage power switching with GTOs

A high-voltage opening switch that uses gate-turnoff thyristors (GTOs) in series and successfully operates at voltages higher than the rated voltage of the individual devices has been demonstrated. The switch design and construction are described, and experimental results are given. The demonstration system is rated at 5 kV and uses 1-kV devices. A larger 24-kV system is under design and will use 4.5-kV devices. In order to design the 24-kV switch, the safe operating area of the large devices must be thoroughly known