A non-unit line protection method for MMC-HVDC grids based on the curvatures of backward traveling waves

Fan Xie, Zhiguo Hao, Dongmeng Ye, Songhao Yang, Chuanxi Li, Guoan Dai, Baohui Zhang, Ting Wang*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)
12 Downloads (Pure)

Abstract

The existing protection techniques for high-voltage direct-current (HVDC) grids suffer from several shortcomings such as high sampling frequency, poor robustness, and reliance on simulation for threshold setting. To solve these problems, this paper proposes a non-unit protection method for modular multilevel converter (MMC)-based HVDC grids using the curvatures of backward traveling waves. To this end, the propagation characteristics of traveling waves and the boundary characteristics of DC lines are first studied, then the analytical expressions of backward traveling waves are derived. Moreover, the curvatures of backward traveling waves are analyzed. On this basis, a non-unit protection method is proposed, including zone selection, disturbance identification, and pole selection. At last, with a protection platform and a real-time digital simulator (RTDS) platform of the MMC-HVDC grid, the accuracy and the robustness of the proposed protection method are verified. The results show that the protection method can correctly identify faults with different distances and resistance in 1 ms and has strong robustness against transition resistance, sampling frequency, boundary value, noise, system topology, and line parameters.

Original languageEnglish
Article number109373
JournalInternational Journal of Electrical Power and Energy Systems
Volume153
DOIs
Publication statusPublished - 2023

Keywords

  • Curvatures
  • HVDC grids
  • Modular multilevel converters
  • Non-unit protection
  • Traveling waves

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