Abstract
Valve-side, single-phase-to-ground (SPG) faults in bipolar high-voltage direct current (HVDC) systems based on half-bridge modular multilevel converters (HB-MMCs) result in i) significant upper arm overvoltage, and ii) non-zero-crossing currents in the grid-side ac circuit breaker (ACCB). In this paper, a dc-link thyristor-based protection scheme is proposed to address both issues. The dc-link thyristor branches are installed in the dc terminal of each station. A dc short-circuit loop is formed following triggering the thyristor branch, redirecting currents from the upper arms to the branch, thus preventing continuous capacitor charging in the upper arms. Moreover, the creation of the dc short-circuit loop induces symmetrical components in the grid side currents, which ensure current zero-crossings in the grid-side ACCB. The peak current flowing into the dc-link thyristor branch is also calculated to facilitate the design of the thyristor branch. The effectiveness of the proposed protection scheme is validated in an HB-MMC HVDC system simulated in PSCAD/EMTDC.
Original language | English |
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Title of host publication | Porceedings of the 50th Annual Conference of the IEEE Industrial Electronics Society |
Publisher | IEEE |
Publication status | Accepted/In press - 2025 |
Event | 50th Annual Conference of the IEEE Industrial Electronics Society - Chicago, United States Duration: 3 Nov 2024 → 6 Nov 2024 |
Conference
Conference | 50th Annual Conference of the IEEE Industrial Electronics Society |
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Country/Territory | United States |
City | Chicago |
Period | 03/11/2024 → 06/11/2024 |
Keywords
- Valve-side ac fault
- Single-phase fault
- HVDC
- MMC
- Thyristor