Development of high-performance thyristor valve using large light-triggered thyristors with 6-inch wafers

Abstract

A thyristor valve for a large HVDC system is required to have such characteristics as compactness in size, smaller power consumption and higher reliability. The authors developed a DC500kV thyristor valve using 8kV light-triggered thyristors with 6-inch wafers which can meet above requirements.
Followings are the results of development and investigation in this paper;
(1) Studies about the rating of thyristors show that a 8kV thyristor with 6-inch wafer can be the most optimum for the objective valve. Newly developed 8kV light-triggered thyristors provide good characteristics.
(2) The most optimum parameters of valve components to keep the valve within its allowable level against the critical stresses are made clear from the quantitative analysis.
(3) An effective test method for valve turn-on test during the arrester discharging is proposed. The test results show that the proposed method can impose proper turn-on stresses on the thyristors.
(4) A DC 500kV proto-valve developed with the aide of above studies shows that it can satisfy the requirements.