Development of a Thyristor Valve for Next Generation 500 kV HVDC Transmission Systems

A high voltage thyristor valve is the basic component of an HVDC transmission system. Development of a 500 kV valve for next generation HVDC transmission systems is described. First, the power loss of the valve is analyzed to decide a reasonable wafer size for the light-triggered thyristor. From these results, a six inch diameter wafer size is selected. A light-triggered thyristor, with ratings of 8 kV and 3.5 kA, is developed using the six inch wafer. The design of the valve employing the thyristor and test results with a prototype valve prove that a 500 kV valve can be realized by this design method.