An Adaptive Fault Ride-Through Scheme for Grid-Forming Inverters under Asymmetrical Grid Faults

Zilin Li, Ka Wing Chan, Jiefeng Hu, Siu Wing Or

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Three-phase four-wire (3P4W) grid-forming (GFM) inverters are promising to interface distributed energy resources (DERs) into low-voltage networks. However, these inverters are prone to overcurrent under grid faults. Physically increasing the inverter current capacity is not cost-effective to cope with complicated fault conditions. In this paper, an adaptive fault ride-through (FRT) scheme based on instantaneous saturators and virtual negative- and zero-sequence resistances is proposed. It features not only overcurrent limitation by modifying voltage references but also seamless transition between normal and grid fault conditions. The proposed FRT scheme is first analyzed from different aspects, including the virtual sequence resistances, grid short-circuit ratio (SCR), fault types, and fault levels. The virtual sequence resistances are then designed to be adaptive to ensure high voltage quality at the healthy phase. The proposed FRT scheme is verified by MATLAB/Simulink simulations under asymmetrical faults. A laboratory platform with a grid-connected 3kW GFM inverter is further constructed to demonstrate its effectiveness. (A video of the experimental results under three asymmetrical faults is attached)

Original languageEnglish
JournalIEEE Transactions on Industrial Electronics
DOIs
Publication statusAccepted/In press - 2021

Keywords

  • Asymmetrical faults
  • Circuit faults
  • current limiting
  • fault ride-through
  • grid-forming inverter
  • Impedance
  • Inverters
  • Limiting
  • Power system stability
  • Synchronization
  • three-phase four-wire
  • virtual impedance
  • Voltage control

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering

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