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  1. Article ; Online: Predicting dynamic stability from static features in power grid models using machine learning.

    Titz, Maurizio / Kaiser, Franz / Kruse, Johannes / Witthaut, Dirk

    Chaos (Woodbury, N.Y.)

    2024  Volume 34, Issue 1

    Abstract: A reliable supply with electric power is vital for our society. Transmission line failures are among the biggest threats for power grid stability as they may lead to a splitting of the grid into mutual asynchronous fragments. New conceptual methods are ... ...

    Abstract A reliable supply with electric power is vital for our society. Transmission line failures are among the biggest threats for power grid stability as they may lead to a splitting of the grid into mutual asynchronous fragments. New conceptual methods are needed to assess system stability that complement existing simulation models. In this article, we propose a combination of network science metrics and machine learning models to predict the risk of desynchronization events. Network science provides metrics for essential properties of transmission lines such as their redundancy or centrality. Machine learning models perform inherent feature selection and, thus, reveal key factors that determine network robustness and vulnerability. As a case study, we train and test such models on simulated data from several synthetic test grids. We find that the integrated models are capable of predicting desynchronization events after line failures with an average precision greater than 0.996 when averaging over all datasets. Learning transfer between different datasets is generally possible, at a slight loss of prediction performance. Our results suggest that power grid desynchronization is essentially governed by only a few network metrics that quantify the networks' ability to reroute the flow without creating exceedingly high static line loadings.
    Language English
    Publishing date 2024-01-25
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472677-4
    ISSN 1089-7682 ; 1054-1500
    ISSN (online) 1089-7682
    ISSN 1054-1500
    DOI 10.1063/5.0175372
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Book ; Online ; Thesis: Agent-based Studies of Collective Phenomena in Supply Network Operation

    Han, Chengyuan [Verfasser] / Witthaut, Dirk [Gutachter] / Schadschneider, Andreas [Gutachter]

    2024  

    Author's details Chengyuan Han ; Gutachter: Dirk Witthaut, Andreas Schadschneider
    Keywords Wirtschaft ; Economics
    Subject code sg330
    Language English
    Publisher Universitäts- und Stadtbibliothek Köln
    Publishing place Köln
    Document type Book ; Online ; Thesis
    Database Digital theses on the web

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  3. Article ; Online: Optimizing the geometry of transportation networks in the presence of congestion.

    Dahlmanns, Matthias / Kaiser, Franz / Witthaut, Dirk

    Physical review. E

    2023  Volume 108, Issue 4-1, Page(s) 44302

    Abstract: Urban transport systems are gaining in importance, as an increasing share of the global population lives in cities and mobility-based carbon emissions must be reduced to mitigate climate change and improve air quality and citizens' health. As a result, ... ...

    Abstract Urban transport systems are gaining in importance, as an increasing share of the global population lives in cities and mobility-based carbon emissions must be reduced to mitigate climate change and improve air quality and citizens' health. As a result, public transport systems are prone to congestion, raising the question of how to optimize them to cope with this challenge. In this paper, we analyze the optimal design of urban transport networks to minimize the average travel time in monocentric as well as in polycentric cities. We suggest an elementary model for congestion and introduce a numerical method to determine the optimal shape among a set of predefined geometries considering different models for the behavior of individual travelers. We map out the optimal shape of fundamental network geometries with a focus on the impact of congestion.
    Language English
    Publishing date 2023-11-17
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2844562-4
    ISSN 2470-0053 ; 2470-0045
    ISSN (online) 2470-0053
    ISSN 2470-0045
    DOI 10.1103/PhysRevE.108.044302
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Dynamic stability of electric power grids: Tracking the interplay of the network structure, transmission losses, and voltage dynamics.

    Böttcher, Philipp C / Witthaut, Dirk / Rydin Gorjão, Leonardo

    Chaos (Woodbury, N.Y.)

    2022  Volume 32, Issue 5, Page(s) 53117

    Abstract: Dynamic stability is imperative for the operation of the electric power system. This article provides analytical results and effective stability criteria focusing on the interplay of network structures and the local dynamics of synchronous machines. The ... ...

    Abstract Dynamic stability is imperative for the operation of the electric power system. This article provides analytical results and effective stability criteria focusing on the interplay of network structures and the local dynamics of synchronous machines. The results are based on an extensive linear stability analysis of the third-order model for synchronous machines, comprising the classical power-swing equations and the voltage dynamics. The article addresses the impact of Ohmic losses, which are important in distribution and microgrids but often neglected in analytical studies. We compute the shift of the stability boundaries to leading order, and thus provide a detailed qualitative picture of the impact of Ohmic losses. A subsequent numerical study of the criteria is presented, without and with resistive terms, to test how tight the derived analytical results are.
    Language English
    Publishing date 2022-04-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472677-4
    ISSN 1089-7682 ; 1054-1500
    ISSN (online) 1089-7682
    ISSN 1054-1500
    DOI 10.1063/5.0082712
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Book ; Online: Stability bounds of droop-controlled inverters in power grid networks

    Böttcher, Philipp C. / Gorjão, Leonardo Rydin / Witthaut, Dirk

    2023  

    Abstract: The energy mix of future power systems will include high shares of wind power and solar PV. These generation facilities are generally connected via power-electronic inverters. While conventional generation responds dynamically to the state of the ... ...

    Abstract The energy mix of future power systems will include high shares of wind power and solar PV. These generation facilities are generally connected via power-electronic inverters. While conventional generation responds dynamically to the state of the electric power system, inverters are power electronic hardware and need to be programmed to react to the state of the system. Choosing an appropriate control scheme and the corresponding parameters is necessary to guarantee that the system operates safely. A prominent control scheme for inverters is droop control, which mimics the response of conventional generation. In this work, we investigate the stability of coupled systems of droop-controlled inverters in arbitrary network topologies. Employing linear stability analysis, we derive effective local stability criteria that consider both the overall network topology as well as its interplay with the inverters' intrinsic parameters. First, we explore the stability of an inverter coupled to an infinite grid in an analytic fashion and uncover stability and instability regions. Secondly, we extend the analysis to a generic topology of inverters and provide mathematical criteria for stability and instability of the system. Last, we showcase the usefulness of the criteria by examining two model systems using numerical simulations. The developed criteria show which parameters might lead to an unstable operating state.

    Comment: 13 pages, 7 figures
    Keywords Electrical Engineering and Systems Science - Systems and Control ; Physics - Physics and Society
    Subject code 621
    Publishing date 2023-03-29
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Formation of trade networks by economies of scale and product differentiation

    Chengyuan Han / Malte Schröder / Dirk Witthaut / Philipp C Böttcher

    Journal of Physics: Complexity, Vol 4, Iss 2, p

    2023  Volume 025006

    Abstract: Understanding the structure and formation of networks is a central topic in complexity science. Economic networks are formed by decisions of individual agents and thus not properly described by established random graph models. In this article, we ... ...

    Abstract Understanding the structure and formation of networks is a central topic in complexity science. Economic networks are formed by decisions of individual agents and thus not properly described by established random graph models. In this article, we establish a model for the emergence of trade networks that is based on rational decisions of individual agents. The model incorporates key drivers for the emergence of trade, comparative advantage and economic scale effects, but also the heterogeneity of agents and the transportation or transaction costs. Numerical simulations show three macroscopically different regimes of the emerging trade networks. Depending on the specific transportation costs and the heterogeneity of individual preferences, we find centralized production with a star-like trade network, distributed production with all-to-all trading or local production and no trade. Using methods from statistical mechanics, we provide an analytic theory of the transitions between these regimes and estimates for critical parameters values.
    Keywords econophysics ; network formation ; phase transitions ; Science ; Q ; Physics ; QC1-999
    Subject code 381
    Language English
    Publishing date 2023-01-01T00:00:00Z
    Publisher IOP Publishing
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Network isolators inhibit failure spreading in complex networks.

    Kaiser, Franz / Latora, Vito / Witthaut, Dirk

    Nature communications

    2021  Volume 12, Issue 1, Page(s) 3143

    Abstract: In our daily lives, we rely on the proper functioning of supply networks, from power grids to water transmission systems. A single failure in these critical infrastructures can lead to a complete collapse through a cascading failure mechanism. ... ...

    Abstract In our daily lives, we rely on the proper functioning of supply networks, from power grids to water transmission systems. A single failure in these critical infrastructures can lead to a complete collapse through a cascading failure mechanism. Counteracting strategies are thus heavily sought after. In this article, we introduce a general framework to analyse the spreading of failures in complex networks and demostrate that not only decreasing but also increasing the connectivity of the network can be an effective method to contain damages. We rigorously prove the existence of certain subgraphs, called network isolators, that can completely inhibit any failure spreading, and we show how to create such isolators in synthetic and real-world networks. The addition of selected links can thus prevent large scale outages as demonstrated for power transmission grids.
    Language English
    Publishing date 2021-05-25
    Publishing country England
    Document type Journal Article
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-021-23292-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Revealing drivers and risks for power grid frequency stability with explainable AI.

    Kruse, Johannes / Schäfer, Benjamin / Witthaut, Dirk

    Patterns (New York, N.Y.)

    2021  Volume 2, Issue 11, Page(s) 100365

    Abstract: Stable operation of an electric power system requires strict operational limits for the grid frequency. Fluctuations and external impacts can cause large frequency deviations and increased control efforts. Although these complex interdependencies can be ... ...

    Abstract Stable operation of an electric power system requires strict operational limits for the grid frequency. Fluctuations and external impacts can cause large frequency deviations and increased control efforts. Although these complex interdependencies can be modeled using machine learning algorithms, the black box character of many models limits insights and applicability. In this article, we introduce an explainable machine learning model that accurately predicts frequency stability indicators for three European synchronous areas. Using Shapley additive explanations, we identify key features and risk factors for frequency stability. We show how load and generation ramps determine frequency gradients, and we identify three classes of generation technologies with converse impacts. Control efforts vary strongly depending on the grid and time of day and are driven by ramps as well as electricity prices. Notably, renewable power generation is central only in the British grid, while forecasting errors play a major role in the Nordic grid.
    Language English
    Publishing date 2021-10-08
    Publishing country United States
    Document type Journal Article
    ISSN 2666-3899
    ISSN (online) 2666-3899
    DOI 10.1016/j.patter.2021.100365
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: BaGe

    Weippert, Valentin / Chau, Thanh / Witthaut, Kristian / Eisenburger, Lucien / Johrendt, Dirk

    Chemical communications (Cambridge, England)

    2021  Volume 57, Issue 11, Page(s) 1332–1335

    Abstract: A new sodalite-type compound, namely ... ...

    Abstract A new sodalite-type compound, namely BaGe
    Language English
    Publishing date 2021-01-11
    Publishing country England
    Document type Journal Article
    ZDB-ID 1472881-3
    ISSN 1364-548X ; 1359-7345 ; 0009-241X
    ISSN (online) 1364-548X
    ISSN 1359-7345 ; 0009-241X
    DOI 10.1039/d0cc07813a
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Mixed Valence and Unusual Germanium Coordination in SrGe

    Weippert, Valentin / Chau, Thanh / Witthaut, Kristian / Johrendt, Dirk

    Inorganic chemistry

    2020  Volume 59, Issue 20, Page(s) 15447–15453

    Abstract: The new Zintl- ... ...

    Abstract The new Zintl-compounds
    Language English
    Publishing date 2020-09-30
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1484438-2
    ISSN 1520-510X ; 0020-1669
    ISSN (online) 1520-510X
    ISSN 0020-1669
    DOI 10.1021/acs.inorgchem.0c02431
    Database MEDical Literature Analysis and Retrieval System OnLINE

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