MMC-HVDC transmission line protection based on Bergeron model and state estimation

This paper presents a novel protection scheme for MMC-HVDC transmission lines. The physical laws that the MMC-HVDC transmission line should obey is firstly described using the Bergeron model, to fully consider distributed shunt capacitance of the line. Afterwards, the proposed protection method checks the consistency between the instantaneous measurements and the model of the MMC-HVDC line under protection and trips the transmission line if any inconsistency is detected. State estimation algorithm is utilized to make full use of the redundancy of available measurements as well as minimize the influence of measurement errors. Simulation results prove that the protection algorithm can quickly and dependably trip internal faults as well as securely ignore external faults, independent of fault type, location and impedances. In addition, the protection algorithm also demonstrates robustness towards measurement errors.