      A contingency analysis done on U.S. power
        grid system using an AC power flow model developed using DMNetwork.
        The input file was obtained from the MatPower package
        (<a href="https://matpower.org/">matpower.org</a>). The total numbers of buses,
        generators, loads, and branches are 82,000,
        13,419, 37,755, and 104,121 respectively. The total number of unknowns solved
        is around half million. The scaling results shows that doubling the number
        of comput