A Memory-Efficient Parallelizable Method for Computation of Thévenin Equivalents used in Real-Time Stability Assessment

Christina Hildebrandt Lüthje Jørgensen*, Jakob Glarbo Møller, Stefan Sommer, Hjörtur Jóhannsson

*Corresponding author for this work

    Research output: Contribution to journalJournal articleResearchpeer-review

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    Abstract

    This paper introduces a factor-solve method, which efficiently computes Thevenin equivalents for all buses in the power system. A range of real-time stability assessment methods rely on Thevenin equivalents, and it is therefore essential that these can be determined fast and efficiently. The factor-solve method has runtime for computing Thevenin voltage that scales linearly with system size resulting in runtime of only a few milliseconds even for systems with several thousand buses. The computations only need the sparse admittance matrix for the power system and a sparse factorization resulting in low memory requirements, and furthermore Thevenin impedances can be determined in parallel. The factor-solve method is compared to a reference method, which uses coefficients for super-position to determine the Thevenin equivalents. The reference method is shown to have dissatisfying runtime and complexity. The factorsolve method is tested, parallelized and analysed, which shows a considerable speed-up in computations of Thevenin equivalents enabling them to be computed in real-time.
    Original languageEnglish
    JournalIEEE Transactions on Power Systems
    Volume34
    Issue number4
    Pages (from-to)2675-2684
    Number of pages9
    ISSN0885-8950
    DOIs
    Publication statusPublished - 2019

    Keywords

    • Algorithms
    • Power system analysis computing
    • Real-time assessment
    • Thevenin equivalent

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