Transient Stability Assessment of Multi-Machine Multi-Converter Power Systems

Brian Johnson

Research output: Contribution to journalArticlepeer-review

52 Scopus Citations


Transmission faults caused by recent wildfires in California induced the disconnection of utility-scale converters in photovoltaic (PV) power plants. Postmortem investigations reported that tripping commands were caused by phase-locked loops (PLLs) and dc-side dynamics, which are typically unmodeled in transient stability studies. Since existing simulation packages rely on simplified models that neglect these dynamics, they have a limited capability to predict converter behavior during faults. To address this shortcoming, we set forth a positive-sequence model for PV power plants that is derived from physics and controls first principles. As seen on utility-scale three-phase converters, the model includes PLLs, dc-side dynamics, and closed-loop controllers. Instances of the developed model are integrated into illustrative power systems containing also conventional generators. Numerical simulations of the obtained multi-machine multi-converter power systems are assessed via a suitable set of stability and performance metrics.
Original languageAmerican English
Pages (from-to)3504-3514
Number of pages11
JournalIEEE Transactions on Power Systems
Issue number5
StatePublished - 2019

NREL Publication Number

  • NREL/JA-5D00-71681


  • photovoltaic systems
  • power system transients


Dive into the research topics of 'Transient Stability Assessment of Multi-Machine Multi-Converter Power Systems'. Together they form a unique fingerprint.

Cite this