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Journal ArticleDOI

MATPOWER: Steady-State Operations, Planning, and Analysis Tools for Power Systems Research and Education

TL;DR: The details of the network modeling and problem formulations used by MATPOWER, including its extensible OPF architecture, are presented, which are used internally to implement several extensions to the standard OPF problem, including piece-wise linear cost functions, dispatchable loads, generator capability curves, and branch angle difference limits.
Abstract: MATPOWER is an open-source Matlab-based power system simulation package that provides a high-level set of power flow, optimal power flow (OPF), and other tools targeted toward researchers, educators, and students. The OPF architecture is designed to be extensible, making it easy to add user-defined variables, costs, and constraints to the standard OPF problem. This paper presents the details of the network modeling and problem formulations used by MATPOWER, including its extensible OPF architecture. This structure is used internally to implement several extensions to the standard OPF problem, including piece-wise linear cost functions, dispatchable loads, generator capability curves, and branch angle difference limits. Simulation results are presented for a number of test cases comparing the performance of several available OPF solvers and demonstrating MATPOWER's ability to solve large-scale AC and DC OPF problems.

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Citations
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Posted Content
TL;DR: In this paper, the authors provide an in-depth analysis of the solution characteristics when convex relaxations are inexact, assess the most promising AC feasibility recovery methods for large-scale systems, and propose two new metrics that lead to a better understanding of the identified solutions.
Abstract: Convex relaxations of AC optimal power flow (AC-OPF) problems have attracted significant interest as in several instances they provably yield the global optimum to the original non-convex problem. If, however, the relaxation is inexact, the obtained solution is not AC-feasible. The quality of the obtained solution is essential for several practical applications of AC-OPF, but detailed analyses are lacking in existing literature. This paper aims to cover this gap. We provide an in-depth investigation of the solution characteristics when convex relaxations are inexact, we assess the most promising AC feasibility recovery methods for large-scale systems, and we propose two new metrics that lead to a better understanding of the quality of the identified solutions. We perform a comprehensive assessment on 96 different test cases, ranging from 14 to 3120 buses, and we show the following: (i) Despite an optimality gap of less than 1%, several test cases still exhibit substantial distances to both AC feasibility and local optimality and the newly proposed metrics characterize these deviations. (ii) Penalization methods fail to recover an AC-feasible solution in 15 out of 45 cases, and using the proposed metrics, we show that most failed test instances exhibit substantial distances to both AC-feasibility and local optimality. For failed test instances with small distances, we show how our proposed metrics inform a fine-tuning of penalty weights to obtain AC-feasible solutions. (iii) The computational benefits of warm-starting non-convex solvers have significant variation, but a computational speedup exists in over 75% of the cases.

26 citations

Journal ArticleDOI
TL;DR: In this paper, three different formulations of the AC optimal power flow problem are compared over different initial conditions, and numerical performance case studies are performed for these formulations over six different classes of initial conditions.
Abstract: This paper examines three different formulations of AC optimal power flow problem and compares performance of well-established general-purpose optimization algorithms for each, over different initial conditions. Polar power–voltage, rectangular power–voltage, and rectangular current–voltage are formulated to evaluate ACOPF solution characteristic. The formulation here maintains line flows as explicit variables and employs summations of these quantities to impose conservation conditions at each node. Two representations of line thermal limits are considered, one using real power (to allow comparisons to dc power flow approximations), and a more physically based ampacity limit using current magnitude. Nonlinear generator capability curves are represented (“D-curves”), including options to allow active and reactive limits dependent on generator voltage. A uniform objective function is used throughout, that of minimizing quadratic generator operating cost curves. Numerical performance case studies are performed for these formulations over six different classes of initial conditions, evaluating computational time and also robustness of convergence.

26 citations

Journal ArticleDOI
TL;DR: The Pareto solutions of this multi-objective TNEP problem are obtained using the Non-dominated Sorting Genetic Algorithm II (NSGA II) that is capable in handling non-convex and non-linear problems with mixed integer structures.

26 citations

Journal ArticleDOI
Tianshu Yang1, Ye Guo1, Lirong Deng1, Hongbin Sun1, Wenchuan Wu1 
TL;DR: Simulations show that the proposed modified DistFlow model has a better accuracy than existing cold-start linear branch flow models, and the resulting MIQP model for reactive power optimization and network reconfiguration is much more computationally efficient than existing benchmarks.
Abstract: This article presents a cold-start linear branch flow model named modified DistFlow In modified DistFlow, the active and reactive power are replaced by their ratios to voltage magnitude as state variables, so that errors introduced by conventional branch flow linearization approaches due to their complete ignoring of network loss terms are reduced Based on the path-branch incidence matrix, branch power flows and nodal voltage magnitudes can be written in succinct matrix forms Subsequently, the proposed modified DistFlow model is applied to the problem of reactive power optimization and network reconfiguration, transforming it into a mixed-integer quadratic programming (MIQP) Simulations show that the proposed modified DistFlow has a better accuracy than existing cold-start linear branch flow models, and the resulting MIQP model for reactive power optimization and network reconfiguration is much more computationally efficient than existing benchmarks

26 citations

Journal ArticleDOI
TL;DR: This paper presents the design of multi-agent based demand response program while considering ac network constraints, and develops two types of information sharing and iterative decision making procedures for the utility and communities to reach Nash equilibrium.

26 citations

References
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Book
01 Jan 1984
TL;DR: In this paper, the authors present a graduate-level text in electric power engineering as regards to planning, operating, and controlling large scale power generation and transmission systems, including characteristics of power generation units, transmission losses, generation with limited energy supply, control of generation, and power system security.
Abstract: Topics considered include characteristics of power generation units, transmission losses, generation with limited energy supply, control of generation, and power system security. This book is a graduate-level text in electric power engineering as regards to planning, operating, and controlling large scale power generation and transmission systems. Material used was generated in the post-1966 period. Many (if not most) of the chapter problems require a digital computer. A background in steady-state power circuit analysis is required.

6,344 citations

Book
01 Jan 1977

1,937 citations

Journal ArticleDOI
TL;DR: This paper describes a simple, very reliable and extremely fast load-flow solution method that is attractive for accurate or approximate off-and on-line routine and contingency calculations for networks of any size, and can be implemented efficiently on computers with restrictive core-store capacities.
Abstract: This paper describes a simple, very reliable and extremely fast load-flow solution method with a wide range of practical application. It is attractive for accurate or approximate off-and on-line routine and contingency calculations for networks of any size, and can be implemented efficiently on computers with restrictive core-store capacities. The method is a development on other recent work employing the MW-?/ MVAR-V decoupling principle, and its precise algorithmic form has been determined by extensive numerical studies. The paper gives details of the method's performance on a series of practical problems of up to 1080 buses. A solution to within 0.01 MW/MVAR maximum bus mismatches is normally obtained in 4 to 7 iterations, each iteration being equal in speed to 1? Gauss-Seidel iterations or 1/5th of a Newton iteration. Correlations of general interest between the power-mismatch convergence criterion and actual solution accuracy are obtained.

1,447 citations

Journal ArticleDOI
TL;DR: The ac power flow problem can be solved efficiently by Newton's method because only five iterations, each equivalent to about seven of the widely used Gauss-Seidel method are required for an exact solution.
Abstract: The ac power flow problem can be solved efficiently by Newton's method. Only five iterations, each equivalent to about seven of the widely used Gauss-Seidel method, are required for an exact solution. Problem dependent memory and time requirements vary approximately in direct proportion to problem size. Problems of 500 to 1000 nodes can be solved on computers with 32K core memory. The method, introduced in 1961, has been made practical by optimally ordered Gaussian elimination and special programming techniques. Equations, programming details, and examples of solutions of large problems are given.

1,112 citations


"MATPOWER: Steady-State Operations, ..." refers methods in this paper

  • ...The default solver is based on a standard Newton’s method [7] using a polar form and a full Jacobian updated at each iteration....

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Journal ArticleDOI
TL;DR: Basic features, algorithms, and a variety of case studies are presented in this paper to illustrate the capabilities of the presented tool and its suitability for educational and research purposes.
Abstract: This paper describes the Power System Analysis Toolbox (PSAT), an open source Matlab and GNU/Octave-based software package for analysis and design of small to medium size electric power systems. PSAT includes power flow, continuation power flow, optimal power flow, small-signal stability analysis, and time-domain simulation, as well as several static and dynamic models, including nonconventional loads, synchronous and asynchronous machines, regulators, and FACTS. PSAT is also provided with a complete set of user-friendly graphical interfaces and a Simulink-based editor of one-line network diagrams. Basic features, algorithms, and a variety of case studies are presented in this paper to illustrate the capabilities of the presented tool and its suitability for educational and research purposes.

890 citations


"MATPOWER: Steady-State Operations, ..." refers background or methods in this paper

  • ...This at least partially explains the lack of a graphical user interface used by some related tools such as PSAT [5]....

    [...]

  • ...A nice summary of their features is presented in [5]....

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