Fault analysis and fast protection of DC bus in MMC-based HVDC grids

摘要

DC bus protection is a key technological problem to be solved in MMC-based HVDC grids. This article mainly deals with fast DC bus protection based on transient characteristic analysis of faults at different location. By building the equivalent grid model, transient fault characteristics of internal and external pole-to-pole faults can be obtained, the difference of which mainly shows in voltage derivative and current change. Then the protection criterions can be set using these two parameters. Finally, simulations in PSCAD/EMTDC verify the effectiveness and sensitivity of proposed protection method.