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This paper presents the stability analysis for a distribution static compensator (DSTATCOM) that operates in current control mode based on bifurcation theory. Bifurcations delimit the operating zones of nonlinear circuits and, hence, the capability to compute these bifurcations is of important interest for practical design. A control design for the DSTATCOM is proposed. Along with this control, a suitable mathematical representation of the DSTATCOM is proposed to carry out the bifurcation analysis efficiently. The stability regions in the Thevenin equivalent plane are computed for different power factors at the point of common coupling. In addition, the stability regions in the control gain space, as well as the contour lines for different Floquet multipliers are computed. It is demonstrated through bifurcation analysis that the loss of stability in the DSTATCOM is due to the emergence of a Neimark bifurcation. The observations are verified through simulation studies. Index Terms--Distribution static compensator (DSTATCOM), floquet multiplier, Neimark bifurcation, point of common coupling (PCC), stability regions.

This paper details a technique in the time domain for the fast periodic steady-state solution of systems with unified power-flow controllers (UPFCs) incorporating three strategies for the practical representation of the UPFC commutation process. The computation of the periodic steady-state solution of power systems with UPFCs including the proposed UPFC control strategies is efficiently obtained by extrapolation to the limit cycle using a Newton method based on a numerical-differentiation procedure. The periodic steady-state solution is validated against the solution obtained with the electromagnetic transient program PSCAD/EMTDC and against an implementation with the power system blockset of SIMULINK. Index Terms--Commutation process, electromagnetic transient program, fast periodic steady state, limit cycle, Newton method, numerical differentiation, unified power-flow controllers (UPFCs).

This contribution deals with the stability analysis of the alternating current arc furnace dynamic operation connected to a supply system using bifurcations theory. The analysis is carried-out in the time domain through the computation of the system eigenvalues and a careful study of the bifurcation diagrams and stability at the equilibrium points. The effect of the bifurcation parameter variation on the arc furnace dynamic behavior is analyzed. The method allows an appropriate assessment of nonlinear oscillations produced by of alternating current Electric Arc Furnace. Index Terms--Alternating current electric arc furnaces, bifurcations, dynamic behavior, eigenvalues, nonlinear oscillations, stability.

This contribution deals with the application of Newton methods based on the Poincare map to accelerate the convergence to the limit cycle and to obtain the periodic steady state solution of electric networks containing Static Var Systems (SVS). A three-phase time domain model for the SVS and the inclusion of the control system required for its automatic operation are presented. This is the first time that a full closed-loop control system has been included in a harmonic-oriented method. Furthermore, a model for the thyristor valves based on elementary functions is presented together with a scheme for determining the switching instants of the valves. Simulation results are compared against measurements taken in the laboratory in a TCR circuit. Index Terms--Limit cycle, Newton methods, Poincare map, SVC, SVS, TCR.

This letter presents the application of a real-time simulation technique to shunt active power filter compensation of the harmonic currents and reactive power in the power system. Available literature details several techniques developed and implemented to perform real-time simulations on the power system analysis. This paper will focus on the following technique: real-time windows target (RTWT) using Matlab/Simulink. Based on the obtained results of the RTWT application, it is possible to obtain simulation conditions that are close to the true real-time environment under study using only a single computer (e.g., the same computer is used as a host and as a target), giving accurate results with relatively low-cost hardware. Index Terms--Active power filter (APF), harmonics, reactive power, real-time application.

This paper introduces an efficient time-domain methodology for the transient and periodic steady-state analysis of the synchronous machine. A state space model of the synchronous machine in phase coordinates is used to accurately represent its transient and steady-state behavior. In the proposed methodology, the transient behavior of the machine is reproduced in detail and once the fault is removed, a Newton technique based on a numerical differentiation (ND) procedure is applied for the acceleration of the convergence of state variables in the time domain to the limit cycle and, thus, for obtaining a fast periodic steady-state solution. The efficiency of the methodology is compared against a brute force (BF) procedure and, in addition, with a widely accepted machine model of an Electromagnetic Transient Program (EMTP-ATP), which is also used for validation purposes. Index Terms--Brute force, Electromagnetic Transient Program, limit cycle, numerical differentiation, periodic steady state, state space, synchronous machine, time domain, transient.