The paper deals with high-voltage tests of thyristor valves for DC transmission. At the beginning, Brief descriptions of various electric stresses appearing on the valves and insulation characteristics of thyristor valves are given. Then, on the basis of relevant research achievements abroad and practical experience on high-voltage tests of thyristor valves for Zhoushan Island DC project(China), The following problems are discussed in detail:Test requirements; Test items; Test methods; Choice of characteris...