Research on Multi‐Terminal Hybrid MMC System DC Fault Clearing Strategy Based on Damped Series Double Sub‐Module
Qiang Zhang, Jifeng Cheng, Junyuan Zhang, Zhaoxin Liang, Peng Yuan, Wansong Liu, Qingxin Wang, Tiantian HeABSTRACT
The onshore flexible DC transmission system has a high fault rate due to lightning strikes and short circuits on overhead lines, etc. In this paper, a topology scheme named damped series double sub‐module (D‐SDSM) with DC fault damping capability is proposed, and the mathematical model, parameter selection, and DC fault clearing strategy of the hybrid MMC based on D‐SDSM and HBSM are researched. Compared with other MMCs with DC fault clearing capability, the hybrid MMC based on D‐SDSM and HBSM is more economical, simpler to control, and has stronger DC fault clearing capability due to the ability to put in damping resistors during blocked. In this paper, a simulation model of the hybrid MMC based on D‐SDSM and HBSM is constructed on the PSCAD with system parameters of 320 kV and 1000 MW, and the influence of the damping resistor value in D‐SDSM on the DC fault clearing process is analyzed, and the effectiveness of the DC fault clearing strategy of the hybrid MMC is verified by taking the four‐terminal system as an example.