Virtual Dynamic Grid Impedance and Its Impacts on Harmonics and Stability of Inverter Based Resources Plant

Himadry Das, Shuhui Li, Bing Lu, Jing Wang

Research output: Contribution to journalArticlepeer-review

3 Scopus Citations


Nowadays, a large number of inverter-based resources (IBRs) are integrated into the grid at a single connection point as an IBR plant. In this article, a virtual dynamic grid impedance concept is introduced to evaluate the harmonics and stability for grid integration of an IBR plant containing multiple IBRs. First, a detailed theoretical study is conducted to build a foundation of the virtual grid impedance concept, which is a dynamic impedance that changes with the number of IBRs added into an IBR plant. Then, based on the new virtual dynamic grid impedance concept, frequency spectrum analysis is performed to explore harmonic impact at the interconnection point for an IBR plant with IBRs having L, LC, and LCL filters, respectively. An electromagnetic transient (EMT) simulation model of a grid-connected IBR plant is developed to explore the harmonics and stability of the IBR plant connected to the grid as well as the reliable operation of IBRs within the plant from the novel virtual equivalent dynamic grid impedance point of view. Hardware experiments are conducted to validate the EMT simulation evaluation. The results show that the number of IBRs added into an IBR plant influences the grid impedance, i.e., grid strength, and the grid impedance variation has multiple impacts on the IBR plant and IBRs within the plant depending on the grid-connected filters of the IBRs.

Original languageAmerican English
Pages (from-to)15469-15481
Number of pages13
JournalIEEE Transactions on Power Electronics
Issue number12
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 1986-2012 IEEE.

NREL Publication Number

  • NREL/JA-5D00-84523


  • grid impedance
  • Grid-connected filters
  • harmonics
  • inverter-based resources (IBRs)
  • stability
  • vector control
  • weak grid


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