Performance of High Voltage Light-Triggered Thyristor Valve

This paper presents performance data for 4kV- 1500A light-triggered thyristors (LTT), developed for use with the thyristor valve for HVDC transmission. A thyristor module consisting of six LTTs connected in series was successfully type-tested and then incorporated into one of existing conventional thyristor valves (125kV-1200A). The field test proved successful. Based on the evaluation result, a 250kV-1800A 1i1ght-triggered thyristor valve was designed. It is shown, from the valve design result, that the LTT valve, as compared with conventional thyristor valves, has higher reliability, maintainability, noise immunity and great flexibility in operation and therefore is expected to contribute to HVDC transmission performance improvement.