Characterization Test and Operational Test for Sub-Modules of 200MW HVDC System-based Modular Multi-Level Converter

Sub-module is the most basic unit of a modular multilevel converter. The design and reliability of a submodule is very important because it determines the performance, efficiency, size, and cost of the HVDC system. This paper describes the configuration of a sub-module developed by Hyosung Co., Ltd. and shows a characteristic test circuit and an operational test circuit to verify the design and performance of the sub-module. The characteristic test is carried out to confirm the dynamic characteristics of a switching device and to verify the design of the sub-module. The operation test is done to verify the performance and protection operation of the sub-module.