Analysis on voltage distribution performance of HVDC thyristor valves

Analysis and simulation on voltage distribution of HVDC thyristor valves under a variety of voltage stress are performed respectively. The summarized influencing factors on voltage distribution indicate that they are different with frequency. Due to the importance and difficulty in approaching even distribution in high frequency, the voltage distribution with different module structure and different power circuit parameters is also investigated in detail. Equivalent circuits are built and circuit analysis method is applied on the basis of “field-circuit coupled method”. It shows that module structure such as framework and module size, module array etc. influence both stray capacitances and equivalent circuit topology, consequently the voltage distribution performance. Besides some power circuit parameters also take great effect. All these key factors are listed and their influences on transient voltage distribution are generally discussed.