Abstract：The short-circuit impedances of converter transformer are important technical parameters in HVDC system. Compared with the traditional converter transformers, the new converter transformer has unique windings connection mode. Based on the peculiar topological structure of the new converter transformer, this paper establishes the mathematical relations of the valve side short-circuit impedance ZK, the grid side short-circuits impedance Zk and the filter impedance Zf, respectively. According to the analysis of the relation of the short-circuit impedances and the filter impedance, the results show that the short-circuit impedance change a little whether or not with filters, so that filters have little effect on the short-circuit impedances, And according to the comparison between the short circuit impedance ZK and Zk, it shows that the both short-circuit impedance are almost the same, so that the short-circuit impedance of the new converter transformer are symmetrical. Finally, the theoretical calculation, simulation and experiment results verify the correctness of the theoretical analysis.
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2012, Vol. 27 
