HYBRID MMC HAVING LOW PROPORTION OF FULL-BRIDGE SUB-MODULES AND DIRECT CURRENT FAULT PROCESSING METHOD

摘要

A hybrid MMC having a low proportion of full-bridge sub-modules and a direct current fault processing method. By artificially manufacturing a three-phase inter-phase short circuit at an alternating current side of a converter in a direct current fault processing process, the hybrid MMC prevents alternating current side energy from entering a direct current system, greatly reducing the proportion of full-bridge sub-modules (FBSM ₁-FBSM _NF) required for the direct current fault processing; moreover, the hybrid MMC having a low proportion of full-bridge sub-modules has the same direct current fault processing speed as a hybrid MMC having a high proportion of full-bridge sub-modules, and the duration of an artificially manufactured three-phase inter-phase short-circuit fault in the fault processing process would not exceed 30 ms, having no large influence on an alternating current system. Compared with an existing submodule hybrid MMC, the hybrid MMC can process direct current faults while using less full-bridge sub-modules (FBSM ₁-FBSM _NF), reducing the number of required power electronic devices and greatly lowering the cost for building an overhead line flexible high-voltage direct-current power transmission system.