A 100-kV thyristor converter for high-voltage dc transmission

This paper discusses the design features and test results of a thyristor power converter for high-voltage dc (HVDC) transmission for study of its practicability. It consists of a thyristor valve (which represents one arm of a bridge) with a bridge output of 100-kV dc. This valve features series use of 120 2.5-kV, 500-ampere thyristors and application of optoelectronics technology where luminous diodes and a light-sensitive device are employed for gate firing, overvoltage protection, and measurement of device-distributed voltage. The tests have confirmed the estimated usability of the thyristor for dc transmission, as well as the superiority and reliability of the optoelectronics. It has been found that the valve performs as designed. With thyristor voltage ratings of over 4 kV already developed in Japan, it is expected that the HVDC power converter will be extensively utilized in the very near future.