This paper studies the submodule configuration of MMC based non-isolated HVDC-DC autotransformer (HVDC-AT) with DC fault blocking capability, including two-terminal and multi-terminal topologies. The operation principle of the HVDC-AT is described. Considering the arm current differences, the total number of required semiconductors for the HVDC-AT is derived and is compared with the MMC based isolated front-to-front (F2F) DC transformer. A full operation process for the multi-terminal HVDC-AT considering DC fault is then presented, including normal operation, fault isolation and continuous operation of healthy converters after fault. The submodule configuration and fault recovery of the multi-terminal HVDC-AT are validated by simulations using PSCAD/EMTDC.
|Number of pages||24|
|Journal||IET Power Electronics|
|Publication status||Accepted/In press - 22 Aug 2016|
- renewable energy
- HVDC technology
- offshore wind power
- modular multilevel converter