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Keywords

flexible HVDC, fault clear of DC line, recovery of fault line, modular multilevel converter(MMC)

Abstract

The modular multilevel converter (MMC) modification combined with the characteristics of DC circuit breakers is one of the economical and feasible solutions to realize the DC fault clearing. Under the background, this paper proposes a MMC modification program based on resistance energyconsuming branches. The scheme realizes the rapid transfer and attenuation of the fault current through the mutual cooperation between the MMC and the additional ports and the resistance energy consumption branch of the line and the shutoff isolation branch. In addition, this solution utilizes the current flowing through the switch module of line resistance energyconsuming branch to accurately determine the fault type, and proposes a restart recovery strategy for the faulty line. Finally, a bipolar direct current transmission (MMCHVDC) system is established in PSCAD to verify the effectiveness of the proposed scheme and the restart recovery strategy of faulty lines. The simulation results show that the proposed scheme has a short fault clearing time and a small fault peak value, and the fault line restart process is stable and reliable.

DOI

10.19781/j.issn.1673-9140.2021.06.008

First Page

67

Last Page

76

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