ParaEMT: An Open Source, Parallelizable, and HPC-Compatible EMT Simulator for Large-Scale IBR-Rich Power Grids

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The electromagnetic transient (EMT) simulation is an essential tool for studying power grids dominated by inverter-based resources (IBRs). However, due to small simulation time steps and increasing problem sizes, performing EMT simulations for large-scale power grids becomes computational-intensive, and often impractical. To address this challenge, we developed ParaEMT, an open-source Python-based EMT simulator that is parallelizable and compatible with high-performance computing (HPC) systems for simulating large-scale power grids with a significant presence of IBRs. Its key features include: 1) utilizing parallel computation for network solution by decomposing the network conductance matrix into the bordered block diagonal form; 2) enabling parallel updates of device states and network historical currents; 3) leveraging HPC to further accelerate simulation through a developed generic interface. The accuracy of ParaEMT has been validated on the reduced 240-bus (720-node) Western Electricity Coordinating Council system by benchmarking the EMT dynamics against PSCAD. Furthermore, ParaEMT achieves a notable speedup of approximately 25 to 36 times on a synthetic 10,080-bus (30240-node) system by leveraging the HPC resource named Eagle at the National Renewable Energy Laboratory. A regional 100% renewable case of the reduced 240-bus system has been developed for simulating system-wide IBRs' interactions in large-scale power grids using ParaEMT.
Original languageAmerican English
Pages (from-to)911-921
Number of pages11
JournalIEEE Transactions on Power Delivery
Issue number2
StatePublished - 2024

NREL Publication Number

  • NREL/JA-5D00-86059


  • bordered block diagonal matrix
  • electromagnetic transient simulation
  • high-performance computing
  • inverter-based resource
  • large-scale systems
  • nodal formulation
  • parallel computation
  • power system dynamics


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