This paper presents an efficient linear system reduction method that computes approximations to the controllability and observability gramians of large sparse power descriptor models. The exploits fact a Lyapunov equation solution can be decomposed into low-rank Choleski factors, which are determined by alternating direction implicit (ADI) method. Advantages it operates on matrices does not require computation spectral projections onto deflating subspaces finite eigenvalues, needed other...

Knowledge of the rightmost eigenvalues system matrices is essential in power small-signal stability analysis. Accurate and efficient computation eigenvalues, however, a challenge, especially for large-scale descriptor systems. In this paper we present an algorithm, based on subspace accelerated Rayleigh quotient iteration (SARQI), automatic (descriptor) matrices. The effectiveness robustness algorithm illustrated by numerical experiments with realistic models, also show how SARQI can be used...

This paper proposes a method for the design of power system controllers aimed at damping out electromechanical oscillations. It can be applied to both stabilizers (PSSs) synchronous generators and supplementary signals associated with other sources. Some attractive features are: parameters all are jointly determined, there is no restriction on type used, controller structures compatible those nowadays employed in electric utilities. The control problem solution exploits sparsity, combining...

This paper compares the computational performances of four model order reduction methods applied to large-scale electric power RLC networks transfer functions with many resonant peaks. Two these require state-space or descriptor system, while third requires only its frequency response data. The fourth method is proposed in this paper, being a combination two previous methods. were assessed for their ability reduce eight test systems, either single-input single-output (SISO) multiple-input...

This paper describes the first reliable Newton algorithm for sequential computation of set dominant poles scalar and multivariable transfer functions infinite systems. pole incorporates a deflation procedure, which is derived from partial fraction expansion concept analytical complex frequency s prevents repeated convergence to previously found poles. The residues (scalars or matrices), are needed in this expansion, accurately computed by Legendre-Gauss integral solver scheme both...

This paper proposes a method for the model order reduction (MOR) of large scale power system models that produces reduced (ROM) which preserve access to selected parameters exactly like original full (FOM). The preserved are related decentralized devices, including, but not limited to, stabilizers used damping control electromechanical oscillations. problem formulation this parametric MOR (PMOR) is described, as well implementation details regarding efficiency and flexibility. Test results...

Summary form only given. This paper presents an efficient linear system reduction method that computes approximations to the controllability and observability gramians of large sparse power descriptor models. The exploits fact a Lyapunov equation solution can be decomposed into low-rank Choleski factors, which are determined by Alternating Direction Implicit (ADI) method. Advantages it operates on matrices does not require computation spectral projections onto deflating subspaces finite...

We investigate, through a kinetic-exchange model, the impact that an external field, like advertising and propaganda, has on opinion dynamics. address situations where two opposite alternatives can be selected but possibility of indecision also exists. In this individuals influence each other pairwise interactions, which agreement or disagreement, there are fields skew decision making. Two parameters used to model interactions with field: one measures sensitivity influenced, another...

This paper proposes a hybrid technique to solve the ill-posed Power Flow Problem (PFP), considering homotopy approach. The primary proposal is large-scale problems where traditional Newton–Raphson (NR) fails converge, as in case of systems. method explores dynamical transient-based improve convergence ill-conditioned problem instead using classical static method. Depending on integration selected scheme and step, result furnished by has low accuracy. Then, NR employed refine low-accuracy...

The combined use of modal and balanced truncations methods is proposed for model order reductions. To efficiently combine these methods, a stopping criterion based on spectral energy concepts also proposed. This was implemented into the code widely known subspace accelerated dominant pole algorithm (SADPA), designed to compute set poles associated residues transfer functions from large‐scale, sparse, linear descriptor systems. resulting enhanced SADPA automatically stops once computed...

This paper proposes a homotopy-based approach to solve the power flow problem (PFP) in islanded microgrid networks with droop-controlled distributed generation (DG) units. The technique is based on modifying an “easy” solution that evolves computation of intermediate results PFP interest. These require nonlinear equations through Newton–Raphson (NR) method. In favor convergence, solutions are close each other, strengthening convergence qualities for DG units modeled operational limits and...

Knowledge of the rightmost eigenvalues system matrices is essential in power small-signal stability analysis. Accurate and efficient computation eigenvalues, however, a challenge, especially for large-scale descriptor systems. In this paper we present an algorithm, based on Subspace Accelerated Rayleigh Quotient Iteration (SARQI), automatic (descriptor) matrices. The effectiveness robustness algorithm illustrated by numerical experiments with realistic models, also show how SARQI can be used...

A fast and accurate model order reduction procedure is presented that can successfully be applied to spectral methods for uncertainty quantification problems. The main novelties include (1) the application of problems; (2) improvement existing in meet accuracy performance requirements; (3) an efficient approach systems with many outputs. Numerical experiments large-scale realistic illustrate suitability (50× speedup while preserving accuracy)

Based on a modal approach, this letter identifies the primary cause for ill-conditioning of Power Flow Problem (PFP) and proposes method to circumvent numerical weakness. The technique consists in modifying ill-conditioned PFP Jacobian matrix standard Newton initial iterate by moving away just its smallest magnitude eigenvalue from near zero. state deviations modified condition is then efficiently computed. This procedure performed adding 1-rank perturbation matrix, but first iteration...

This paper presents results of the implementation and description basic formulation for Holomorphic Embedding Load Flow Method (HELM). The approach is a noniterative technique proposed as an alternative method to solve power flow problem. implemented by generation interface use data structure traditional MATPOWER. free code tool which developed in Matlab. Additionally, same files this are used input study carried out work. Also, output adapted have similar characteristics MATPOWER's output....

Attention is focused on the efficient application of optimal control methods with structural constraints to large power systems. A novel framework for linear-quadratic regulator problems proposed which allows use matrix and vector sparsity techniques in solution process. Results concerning method's computational performance as applied a 750-bus, 40-machine networks are provided.

This paper proposes a new approach for accelerating the convergence runtime of modified Holomorphic Embedding Load-Flow Method (HELM). In this adaptive HELM it is not used flat start, nor an aleatory Initial Guess, but previous starting solution provided by iterative method based on Newton Krylov subspace. It proposed, to improve Adaptive HELM-based strategy, applying use BiCGStab (Bi-Conjugate Gradient Stabilized) method, preconditioning, incomplete LU factorization, and reordering...