Category: Submitted

@inproceedings{GrosTren18,
title = {Switch induced instabilities for stable power system DAE models},
author = {Tjorben B. Gross and Stephan Trenn and Andreas Wirsen},
url = {http://stephantrenn.net/wp-content/uploads/2018/04/Preprint-GTW180413.pdf, Preprint},
year = {2018},
date = {2018-07-11},
booktitle = {Proc. IFAC Conf. Analysis Design Hybrid Systems (ADHS 2018)},
journal = {IFAC-PapersOnLine},
abstract = {It is well known that for switched systems the overall dynamics can be unstable despite stability of all individual modes. We show that this phenoma can indeed occur for a linearized DAE model of power grids. By making certain topological assumptions on the power grid, we can ensure stability under arbitrary switching.},
note = {to appear},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}

@unpublished{PatiTesi17pp,
title = {Indiscernible topological variations in DAE networks},
author = {Deepak Patil and Pietro Tesi and Stephan Trenn},
url = {http://stephantrenn.net/wp-content/uploads/2017/11/Preprint-PTT171123.pdf, Preprint},
year = {2017},
date = {2017-11-23},
abstract = {A problem of characterizing conditions under which a topological change in a network of differential algebraic equations (DAEs) can go undetected is considered. It is shown that initial conditions for which topological changes are indiscernible belong to a generalized eigenspace shared by the nominal system and the system resulting from a topological change. A condition in terms of eigenvectors of the nominal system is derived to check for existence of possibly indiscernible topological changes. For homogenous networks this conditions simplifies to existence of an eigenvector of the Laplacian of network having equal components. Lastly, a rank condition is derived which can be used to check if a topological change preserves regularity of the nominal network.},
keywords = {},
pubstate = {published},
tppubtype = {unpublished}
}

@inproceedings{KustPati17a,
title = {Indiscernible topological variations in DAE networks with applications to power grids},
author = {Ferdinand Küsters and Deepak Patil and Pietro Tesi and Stephan Trenn},
url = {http://stephantrenn.net/wp-content/uploads/2017/09/Preprint-KPTT170320.pdf, Preprint},
doi = {10.1016/j.ifacol.2017.08.1478},
issn = {2405-8963},
year = {2017},
date = {2017-03-24},
booktitle = {Proc. 20th IFAC World Congress 2017},
journal = {IFAC-PapersOnLine},
volume = {50},
number = {1},
pages = {7333 - 7338},
address = {Toulouse, France},
abstract = {The ability to detect topology variations in dynamical networks defined by differential algebraic equations (DAEs) is considered. We characterize the existence of initial states, for which topological changes are indiscernible. A key feature of our characterization is the ability to verify indiscernibility just in terms of the nominal topology. We apply the results to a power grid model and also discuss the relationship to recent mode-detection results for switched DAEs.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}

@unpublished{TanwTren17pp,
title = {Detectability and Observer Design for Switched Differential Algebraic Equations},
author = {Aneel Tanwani and Stephan Trenn},
url = {http://stephantrenn.net/wp-content/uploads/2017/11/Preprint-TT171116.pdf, Preprint},
year = {2017},
date = {2017-11-16},
abstract = {This paper studies detectability for switched linear differential-algebraic equations (DAEs) and its application to the synthesis of observers, which generate asymptotically converging state estimates.
Equating detectability to asymptotic stability of zero-output-constrained state trajectories, and building on our work on interval-wise observability, we propose the notion of interval-wise detectability: If the output of the system is constrained to be identically zero over an interval, then the norm of the corresponding state trajectories scales down by a certain factor at the end of that interval. Conditions are provided under which the interval-wise detectability leads to asymptotic stability of zero-output-constrained state trajectories.
An application is demonstrated in designing state estimators. Decomposing the state into observable and unobservable components, we show that if the observable component of the system is reset appropriately and persistently, then the estimation error converges to zero asymptotically under the interval-wise detectability assumption.
},
keywords = {},
pubstate = {published},
tppubtype = {unpublished}
}