%0 Journal Article %T The N-K Problem in Power Grids: New Models, Formulations and Numerical Experiments (extended version) %A Daniel Bienstock %A Abhinav Verma %J Mathematics %D 2009 %I arXiv %X Given a power grid modeled by a network together with equations describing the power flows, power generation and consumption, and the laws of physics, the so-called N-k problem asks whether there exists a set of k or fewer arcs whose removal will cause the system to fail. The case where k is small is of practical interest. We present theoretical and computational results involving a mixed-integer model and a continuous nonlinear model related to this question. %U http://arxiv.org/abs/0912.5233v2