Reduce-Factor-Solve for Fast Thevenin Impedance Computation and Network

Stefan Sommer*, Andreas Aabrandt, Hjörtur Jóhannsson

*Corresponding author for this work

    Research output: Contribution to journalJournal articleResearchpeer-review

    327 Downloads (Pure)


    The complexity and volatility of power system operation increases when larger parts of the power production is based on distributed and non-controllable renewable energy sources. Ensuring stable and secure operation becomes more difficult in these modern power systems. For security assessment, the results of traditional offline simulations may become obsolete prior to the completion of the assessment. In contrast, real-time stability and security assessment aims at online computation, and it is therefore dependent on very fast computation of properties of the grid operating state. The paper develops the reduce-factor-solve approach to real-time computation of two key components in real-time assessment methods, network reduction and calculation of Thevenin impedances. The aim is to allow online stability assessment for very complex networks. The theoretical foundation behind the reduce-factor-solve approach is described together with the ability to handle both algorithms in a common framework. By exploiting parallelization of the reduce and solve steps in combination with fast matrix factorization, Thevenin impedances and reduced networks are computed much faster than previous approaches. The reduce-factor-solve algorithm is evaluated on power grids of varying complexity to show that Thevenin impedance computation and network reduction for complex power systems can be performed on a milliseconds time scale.
    Original languageEnglish
    JournalI E T Generation, Transmission and Distribution
    Issue number2
    Pages (from-to)288-295
    Publication statusPublished - 2018


    Dive into the research topics of 'Reduce-Factor-Solve for Fast Thevenin Impedance Computation and Network'. Together they form a unique fingerprint.

    Cite this