Application of synthetic test method in short-circuit current tests for voltage source converter based high voltage direct current valves

Synthetic test method is such a test approach, which provides required stresses for test sample under different operational conditions during the operation test respectively by multi-sets of power suppliers. To examine the design validity of converter valve in voltage source converter-based high voltage direct current (VSC-HVDC) based on modular multi-level converter (MMC) and its stress tolerance under transient operation condition, an approach to perform transient state operation test for valves in MMC is researched. The stresses related to overcurrent turn-off test and short-circuit current test are analyzed, then two equivalent test methods are proposed and synthetic test method is applied in the design of testing circuit and then the stress waveforms of testing circuit and that under practical operation conditions are given. Combining with the analysis on equivalence of key stresses, the correctness and effectiveness of above-mentioned test method and testing circuit are verified.