| Abstract |
The Modular Multilevel Converter (MMC) technology brings several advantages, although its operation and protection are very different compared to conventional Voltage Source Converters (VSC). Short circuit faults at the DC link transmission systems of MMCs that use the Half-Bridge Submodule (HB-SM) are still a major concern due to potentially high fault current magnitudes. The sequence of the pole-to-pole DC short circuit of an HB-MMC is analyzed and modeled through respective equivalent circuits. A simplified calculation is presented that allows estimating the current magnitudes after the DC-fault appearance. Finally, several protection measures for the HB-MMC are described, and a new protection method that uses an AC crowbar is introduced and analyzed. |
