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@PHDTHESIS{Lemkens:464551,
      author       = {Lemkens, Stephan},
      othercontributors = {Koster, Arie M. C. A. and Triesch, Eberhard},
      title        = {{S}tructural {P}roperties of {L}inearized {P}ower {F}lows
                      and {P}ower {G}rid {D}esign},
      school       = {Aachen, Techn. Hochsch.},
      type         = {Dissertation},
      address      = {Aachen},
      publisher    = {Publikationsserver der RWTH Aachen University},
      reportid     = {RWTH-2015-01361},
      pages        = {VII, 254 S. : Ill., graph. Darst., Kt.},
      year         = {2015},
      note         = {Aachen, Techn. Hochsch., Diss., 2015},
      abstract     = {In this thesis we linearize the power flow and power grid
                      design problem and analyze the mathematical properties of
                      these problems. We introduce a linearization which takes
                      care of some of the drawbacks of the well-established DC
                      formulation. The DC formulation is an approximation of the
                      nonlinear power flow equations, useful for deriving an
                      approximation of the active power flow. Our new
                      linearization, called AC-linear, is based on Taylor
                      expansion of the nonlinear formulation and yields
                      information on active and reactive flows. We show that it is
                      a generalization of the often used DC formulation. Our main
                      contribution is the thorough analysis of the newly
                      introduced AC-linear formulation. We show the existence of
                      combinatorial structures in the problem, which involve the
                      class of bispanning graphs. The first part concludes with a
                      computational comparison of the quality of the two discussed
                      linearizations. We are able to show, that the AC-linear
                      formulation is superior to the DC one when interested in
                      active and reactive flow information. The second part of
                      this work considers the impact of the new linearization on
                      the power grid design problem. We therefore study the
                      computational complexity of various power grid design
                      problems and show that a special formulation of the DC
                      problem can be considered as a partition problem without the
                      involvement of power flow equations. We show that this does
                      no longer hold for the generalized formulation. As the set
                      of feasible power grid designs is given by a polytope, we
                      thoroughly study its structure for both formulations. We
                      then give an in depth analysis of a special case of the DC
                      power grid design polytope, where the polytope's dimension
                      is easily determinable. We are able to derive facets for the
                      polytope, utilizing results of both the connected-subgraph
                      and the knapsack polytope. We then perform a computational
                      study in order to determine the tractability of the two
                      linearizations on modern integer programming solvers. While
                      the DC model significantly outperforms the AC-linear one,
                      its computed designs do not allow for a feasible AC power
                      flow. We show that the designs derived by using the
                      AC-linear formulation are superior with regards to this
                      property. Thus the newly introduced formulation allows for a
                      more accurate approximation of the power grid design
                      problem.},
      cin          = {113320 / 110000},
      ddc          = {510},
      cid          = {$I:(DE-82)113320_20140620$ / $I:(DE-82)110000_20140620$},
      typ          = {PUB:(DE-HGF)11},
      urn          = {urn:nbn:de:hbz:82-rwth-2015-013612},
      url          = {https://publications.rwth-aachen.de/record/464551},
}