A design method of MMC-HVDC physical simulation system
For the growing power rating and voltage level, modular multilevel converter (MMC) is a feasible solution in the application of voltage sourced converter based high voltage direct current(VSC-HVDC) transmission. However, due to its numerous independently controlled sub-modules(SMs), it is very difficult to represent the complete internal transient process of MMC or accomplish the hardware-in-loop (HIL) test of valve based controller (VBC) using digital simulation platform. Therefore, this paper deduces the similarity criterions and the parameter calculation method for the design of low-voltage physical simulation system. Taking the Xiamen ± 3 20kV/1000MW MMC-HVDC project in China as a simulation prototype, a physical simulation system is built, based on which the type test of VBC and system operation analysis are completed. Experiment results verify the correctness of the proposed calculation method and the designed system.