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This paper presents a comprehensive study about a Simplified Rail Power Conditioner (SRPC) based on a half-bridge indirect AC/DC/AC Modular Multilevel Converter (MMC) and a V/V traction power transformer. The proposed system with a half-bridge MMC can decrease the costs, reduce the control complexity, and require less hardware devices in comparison with the rail power conditioner based on a full-bridge...
Power quality simulation is required to provide an evaluation of the adverse phenomena such as transients, harmonics, and voltage sags in a power system, among others. This paper details a methodology to assess adverse power quality effects. In this methodology, the power system is modeled in the continuous-time by an ordinary differential equations set. The equations set are solved through a numerical...
Separation of contribution from supply side and customer side in generation of harmonics in power system is an important problem to be addressed. This paper presents a method to estimate the harmonics present in the supply side by making a few measurements at the point of common coupling. The method involves determination of network harmonic impedance by a noninvasive procedure. The normal operation...
This paper verifies the importance of load modeling for the harmonic assessment of power systems. Three different models are discussed, and the impact of each approach on the harmonic evaluation of power networks is highlighted. Through this discussion, a Harmonic Coupled Norton Equivalent (HCNE) model is pointed out as a suitable approach to represent the behavior of harmonic producing loads. A methodology...
This paper presents how the PWM controlled AC locomotives are disturbing the electric network with harmonics. Previously the so called double domain simulation method was published. The double domain simulation is suitable for studying the different filtering methods, like the passive, active and hybrid filtering. In this paper the combination possibility with AC locomotives are discussed. The double...
An AC arc furnace is an unbalanced, nonlinear and time varying load, which can cause many problems to power system quality. Different studies on arc furnaces harmonics analysis can be found in the bibliography on the topic; however, it is very difficult obtain an exact model that takes into account all the parameters that have influence on the process, therefore it is necessary to take measurements...
This paper reports investigation on power quality aspects of wind generation by means of a state space model of fixed-speed turbines. Variable wind speed is assumed to be applied at the wind park; the generation of flicker, harmonics and inter-harmonics is analyzed. Dependency of these effects on the variations in the wind speed is analyzed. The harmonics and inter-harmonics spectrum is obtained using...
This paper investigates the interactions which arise between grid connected photovoltaic inverter systems and the electrical grid. In particular, it considers the effect of grid voltage harmonics and grid impedance on the current control performance of grid connected inverter systems. In these photovoltaic inverter systems it is usual to control unity power factor, sinusoidal, current into the grid...
Due to the increasing use of nonlinear loads, the associated power quality (PQ) problems have become a major concern to many electric utilities and their customers. For efficient and accurate analysis, the performance of computer simulation has been recognized as an important and necessary procedure to the power quality study. With the advanced development of computer and communication technologies,...
Voltage flicker and harmonics are the power quality problems which are introduced to the power system as a result of nonlinear and stochastic behavior of the arc furnace operation. In the first part of the paper, different arc furnace models with different level of complexity, for flicker study are reviewed. Simulation results are also provided. In the second part of the paper, a new developed time...
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