In order to achieve the comprehensive assessment of the steady stress and the transient stress by DC side bipolar fault of voltage source converter based high voltage direct current(VSC-HVDC)valves

an undelayed synthetic test method with high junction temperature for VSC-HVDC is proposed. The switching devices of the converter valves is guaranteed to be at the highest junction temperature state when the short circuit current is injected. At the same time

the costs and power requirements of the converter valves test have been effectively reduced by proposed method. Firstly

the electric stress of steady-state operation and DC side bipolar fault of VSC-HVDC valves is studied. Secondly

based on the stress equivalence mechanism of VSC-HVDC valves

an undelayed synthetic test with high junction temperature for VSC-HVDC valves is presented. Thirdly

the test operation mechanism is expounded. Finally

the validity of the synthetic test method and its circuit topology are verified by simulation model and test platform.