Title: Research on fault isolation method for composite fault in power module of modular multilevel converter

Authors: Yue Mo; Ming Liu; Feng Zheng; Zetao Li

Addresses: Tianshengqiao Branch of Extra High Voltage Power Transmission Company, China Shouthern Power Grid Co., Ltd., Xingyi, Guizhou, 562400, China ' Electrical Engineering College, Guizhou University, Guiyang, Guizhou, 550025, China ' Tianshengqiao Branch of Extra High Voltage Power Transmission Company, China Shouthern Power Grid Co., Ltd., Xingyi, Guizhou, 562400, China ' Electrical Engineering College, Guizhou University, Guiyang, Guizhou, 550025, China

Abstract: The fault diagnosis technology of modular multilevel converter has important engineering significance. Isolation of composite fault is a difficult problem in fault diagnosis. In this paper, the isolation method of composite fault in modular multilevel converter power module is studied. The structural fault is modelled. The isolation problem of parametric fault superimposed with structural faults is discussed. A composite fault isolation method for power module of modular multilevel converter is established. Aiming at the problem of gradualy closing of fault isolability window caused by structural fault, an offline fault isolation method for power module composite fault based on dynamic trajectory is proposed. Simulation experiment shows the effectiveness of the proposed method.

Keywords: modular multilevel converter; MMC; power module; fault isolation; multiple faults; structural faults; observer.

DOI: 10.1504/IJMIC.2021.10048044

International Journal of Modelling, Identification and Control, 2021 Vol.39 No.2, pp.83 - 96

Received: 25 Jan 2021
Accepted: 02 Apr 2021

Published online: 20 Jun 2022 *

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