Improving an interior-point-based OPF by dynamic adjustments of step sizesand tolerances

This paper presents an efficient interior point algorithm for Optimal Power Flow (OPF) problems, in particular, the real power dispatch and the reacti ve power dispatch problems. The nonlinear OFF problem is solved by a predic tor-corrector primal-dual log-barrier (PCPDLB) method as a sequence of line arized sub-problems. Besides discussing the problem formulation, the paper offers a detailed description of the PCPDLB algorithm; it also addresses se veral implementation issues such as the determination of barrier parameter and the customization of initial points for OFF problems. In addition, prac tical issues on how to choose linear step sizes and convergence criteria ar e investigated to evaluate their impact on the performance of the algorithm . Some heuristics of dynamically adjusting step sizes and tolerance are pro posed which significantly improve OFF solution speed. Computational results on power systems of 118 and 1062 buses are presented and discussed. Compar isons with other variants of primal-dual log-barrier methods are also provi ded to demonstrate the superiority of the proposed predictor-corrector inte rior point algorithm.