Analysis on the Deterioration of the Withstand Voltage Level of HVDC Thyristors

This paper analyzes a DC blocking event caused by the reduction of the voltage withstand level of the thyristor of the converter valve in the DC transmission system, It is found that the influence of the adhesion force of silicon seal on the withstand voltage characteristics of thyristor components provides a reference for the fault location and rectification of the decline in the withstand voltage ability of similar thyristors in DC transmission projects.