Title |
Circuit Configuration of Asymmetric Mixed MMC in Bipolar HVDC Transmission Systems |
DOI |
https://doi.org/10.5370/KIEE.2020.69.3.435 |
Keywords |
bipolar HVDC system; hybrid MMC; modular multilevel converter; SLG fault; system reliability |
Abstract |
Among the MMC topologies for bipolar HVDC systems, the asymmetric mixed MMC is considered as promising and attractive circuit due to the cost saving, less loss, DC fault ride-through capability, and free and quick DC bus voltage regulation. In this paper, the reasonable circuit configuration of an asymmetric mixed MMC in bipolar HVDC transmission system is introduced. In the application of asymmetric mixed MMC for the bipolar HVDC system, the induced DC bias voltage into AC transformer at normal operation according to the placement of submodules is investigated and discussed. Furthermore, the optimal submodule arrangement is proposed considering the busbar single line-to-ground fault at AC side of MMC. |