Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Thyristor-pair- and damping-submodule-based protection against valve-side single-phase-to-ground faults in MMC-MTDC systems

Lui, Xiaoxiao, Li, Gen, Zheng, Tao, Yang, Xinhui and Guerrero, Josep M. 2021. Thyristor-pair- and damping-submodule-based protection against valve-side single-phase-to-ground faults in MMC-MTDC systems. IEEE Transactions on Power Delivery 10.1109/TPWRD.2021.3125661

[thumbnail of TPWRD-00627-2021.pdf]
Preview
PDF - Accepted Post-Print Version
Download (5MB) | Preview

Abstract

The single-phase-to-ground (SPG) fault at the valve side of the converter transformer is one of the most critical faults threatening the operation of bipolar half-bridge modular-multilevel-converter-based multi-terminal direct-current (HB-MMC MTDC) systems. Following a valve-side SPG fault, the upper-arm submodule (SM) capacitors in the faulty converter may suffer a serious overvoltage, and the grid-side fault currents may experience no zero-crossings. The existing protection methods generally rely on tripping the grid-side alternate-current circuit-breaker (ACCB), which cannot fully isolate the fault. The healthy poles and stations may encounter severe disturbance and be all blocked, which will lead to a power outage of the entire MTDC system. This paper proposes an ACCB-independent scheme based on thyristor-pairs and damping SMs to address these problems. Antiparallel thyristor-pairs are connected in series within the upper and lower arms in each phase. Serial damping SMs are connected within the lower arms to help the lower-arm thyristor pairs cut off the fault currents. Although the proposed additional devices inevitably cause conduction losses, they can effectively protect the faulty converter and healthy circuit in the MTDC system. Simulations in PSCAD/EMTDC have been conducted to verify the effectiveness of the proposed strategy.

Item Type: Article
Date Type: Published Online
Status: In Press
Schools: Engineering
Publisher: Institute of Electrical and Electronics Engineers
ISSN: 0885-8977
Date of First Compliant Deposit: 3 November 2021
Date of Acceptance: 31 October 2021
Last Modified: 10 Nov 2021 15:42
URI: https://orca.cardiff.ac.uk/id/eprint/145283

Actions (repository staff only)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics