Inverter-Based Operation of Maui: Electromagnetic Transient Simulations

Andy Hoke, Wallace Kenyon, Bin Wang, Jin Tan, Gemini Yau, Marc Asano, Lisa Dangelmaier

Research output: NRELPresentation


As larger and larger power systems approach and reach 100% inverter-based resource (IBR) operation during some hours of the year, questions arise regarding the stability of such extremely-high IBR power systems, the potential need for grid-forming (GFM) inverter technology, and the potential need for synchronous condensers. Relatedly, questions also arise about the ability of conventional positive sequence power system modeling tools to capture high-IBR system dynamics. This presentation introduces electromagnetic transient (EMT) simulations in PSCAD of the near-future (year 2023) Maui power system at and near 100% IBR operation and compares those simulations to positive sequence (PSSE) simulations. The Maui PSCAD model is parallelized on 30 cores and includes the entire transmission system (>200 three-phase buses), >170 individual and aggregate IBR models, four wind plants, and three synchronous generators plus six synchronous condensers at two locations. We investigate system stability with varying levels of inertia using conventional grid-following IBR controls, and then we investigate the impact of GFM controls on stability. Results suggest that: 1) positive sequence simulations can miss key dynamics in extremely high IBR cases; 2) EMT simulations can also miss key dynamics if inverter inner control dynamics are not modeled; 3) synchronous condensers can stabilize a system in which 100% of the energy is supplied by IBRs, even conventional grid-following IBRs; 4) GFM controls on just some of the IBRs can stabilize a 100% IBR power system, even if that system has zero inertia (i.e. no synchronous condensers, though synchronous condensers may be needed for other purposes such as protection system operations).
Original languageAmerican English
Number of pages26
StatePublished - 2021

Publication series

NamePresented at the Inverter-Based Resource Performance Working Group (IRPWG), 24 March 2021

NREL Publication Number

  • NREL/PR-5D00-79852


  • electromagnetic transient simulation
  • grid-forming inverters
  • inverter-based resources
  • island power systems
  • power system stability


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