A New Current Limiting and Overload Protection Scheme for Distributed Inverters in Microgrids under Grid Faults

Zilin Li, Jiefeng Hu, Ka Wing Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

1 Citation (Scopus)


Unlike a synchronous generator that could withstand a large overcurrent, an inverter-based distributed generation (DG) has low thermal inertia, and the inverter is likely damaged by overcurrents during grid faults. In this article, a new strategy, namely positive-And negative-sequence limiting with stability enhanced P-f droop control (PNSL-SEPFC), is proposed to limit the output currents and active power of droop-controlled inverters in islanded microgrids. This strategy is easy to implement in the inverter controller and does not require any fault detection. Inverter stability is analyzed mathematically, which gives guidelines to design the parameters of the PNSL-SEPFC strategy. PSCAD/EMTDC simulation based on a four-DG microgrid shows that the proposed PNSL-SEPFC can limit inverter output currents and powers with better performance under both symmetrical and asymmetrical faults. Furthermore, hardware experiments demonstrate that the proposed PNSL-SEPFC can ensure the inverters riding through grid faults safely and stably. (A video of experimental waveforms is attached.).

Original languageEnglish
Pages (from-to)6362-6374
Number of pages13
JournalIEEE Transactions on Industry Applications
Issue number6
Publication statusPublished - Aug 2021


  • Current limiting
  • droop control
  • fault-ride-Though capability
  • grid-forming inverter
  • transient stability

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering

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