Bypass arm based DC fault isolation scheme for MMC-HVDC systems

Wang, Yaoqiang, Sun, Ruyin, Guo, Yanxun, Wang, Kewen and Liang, Jun ORCID: https://orcid.org/0000-0001-7511-449X 2023. Bypass arm based DC fault isolation scheme for MMC-HVDC systems. Journal of power electronics 23 , pp. 1232-1242. 10.1007/s43236-023-00618-y

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Abstract

High voltage direct current transmission based on a modular multilevel converter (MMC-HVDC) is an effective method to solve the grid connection of the new energy. A DC fault is an issue that must be solved for MMC-HVDC. This paper proposes a protection scheme for HVDC converters to quickly suppress DC fault current without increasing the operation loss. By employing a bypass arm in conjunction with a switch-type zero-loss current limiter (SZCL), most of the DC current in the bridge arm flows through the bypass arm so the fault current of the power devices is reduced. There are a number of main advantages of this scheme. The fault isolation time can be greatly shortened, the cost of the system is effectively reduced, the steady-state operation loss of the system does not increase, the operation of the AC-grid can be maintained stably when a DC fault occurs, and the overcurrent impulse to the AC-grid is reduced. The proposed scheme is applicable to two-terminal systems and the DC grid, especially for faults at the converter outlet of the DC grid. Simulation results using PSCAD/EMTDC show the superiority of the proposed scheme when compared with other schemes and a comparison of the costs shows the feasibility of the proposed scheme in practical applications.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Engineering
Publisher:	Springer
ISSN:	1598-2092
Date of First Compliant Deposit:	6 April 2023
Date of Acceptance:	14 February 2023
Last Modified:	11 Nov 2024 19:30
URI:	https://orca.cardiff.ac.uk/id/eprint/157879

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