This paper presents a novel method to approximate the nonlinear AC optimal power flow (OPF) into tractable linear/ quadratic programming (LP/QP) based OPF problems that can be used for power system planning and operation. We derive a linear power flow approximation and include a convex reformulation of the power losses in the form of absolute value functions. We show three ways how we can incor...

In this work, we present a new parallel-driven approach to speed up Optimum-Path Forest (OPF) training phase. In addition, we show how to make OPF up to five times faster for training using a simple parallel-friendly data structure, which can achieve the same accuracy results to the ones obtained by traditional OPF. To the best of our knowledge, we have not observed any work that attempted at p...

OBJECTIVES/HYPOTHESIS To evaluate the osteoplastic flap (OPF) procedure for frontal sinus pathology at our institution, including indications, revisions, obliteration vs. nonobliteration, and obliteration materials. STUDY DESIGN Single-institution retrospective review from 1998 to 2013. METHODS Current Procedural Terminology codes identified all OPF procedures. Demographic data, diagnoses, ...

The set of optimization problems in electric power systems engineering known collectively as Optimal Power Flow (OPF) is one of the most practically important and well-researched subfields of constrained nonlinear optimization. OPF has enjoyed a rich history of research, innovation, and publication since its debut five decades ago. Nevertheless, entry into OPF research is a daunting task for th...

This paper is based on material presented at the IEEE 1995 Winter Power Meeting Panel Session on Challenges to OPF, sponsored by the IEEE Working Group on Operating Economics. The paper contains a brief summary of the session followed by summaries. INTRODUCTION J.A. Momob, Senior Member Howard University Washington, DC The increasing demand for an OPF tool for assessing state and recommended co...

When uncontrollable resources fluctuate, optimal power flow (OPF), routinely used by the electric power industry to redispatch hourly controllable generation (coal, gas, and hydro plants) over control areas of transmission networks, can result in grid instability and, potentially, cascading outages. This risk arises because OPF dispatch is computed without awareness of major uncertainty, in par...

The optimal power-flow problem (OPF) has always played a key role in the planning and operation of power systems. Due to the non-linear nature of the AC power-flow equations, the OPF problem is known to be non-convex, therefore hard to solve. Most proposed methods for solving the OPF rely on approximations (e.g., of the network model) that render the problem convex, but that consequently yield ...

In this work we have proposed an innovative and accurate solution for non-technical losses identification using the Optimum-Path Forest (OPF) classifier and its learning algorithm. Results in two datasets demonstrated that OPF outperformed the state of the art pattern recognition techniques and OPF with learning achieved better results for automatic nontechnical losses identification than recen...

In this paper we describe an Interior Point Method (IPM) to solve large scale NonLinear Programming (NLP) problems, tailored to the solution of a specialized Optimal Power Plow (OPF) formulation that uses bus voltages in rectangular coordinates. The distinctive feature of this OPF formulation is that the objective function and constraints are quadratic functions, and such quadratic properties a...

The optimal power-flow problem (OPF) has always played a key role in the planning and operation of power systems. Due to the non-linear nature of the AC power-flow equations, the OPF problem is known to be non-convex, therefore hard to solve. Most proposed methods for solving the OPF rely on approximations (e.g., of the network model) that render the problem convex, but that consequently yield ...