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Summary: In the context of procedures aimed at quantifying the contribution of a particular installation concerning the total harmonic distortions present at a point, one notes the absence of a reliable procedure with a solid and feasible foundation of practical application. Seeking to bridge this gap, the present paper proposes the dominant impedance method to assign harmonic voltage contributions at a particular bus on the electric power system. To illustrate the suitability of the methodology referred to herein, computer simulations are studied on an electric system with characteristics correlated to real complexes. In addition, analyses are made of the practical results obtained from the employment of the procedure on a laboratorial system, which retains approximately the same characteristics as those investigated in the simulations, albeit, on a reduced scale. [ABSTRACT FROM AUTHOR]

Discussions regarding reliable and feasible methods for assignment of harmonic distortion contributions in real systems have received widespread interest in the Power Quality area. The present article proposes a new methodology for determining the portion of contribution of a particular installation, in relation to the total harmonic voltage distortion verified at its point of connection. The method proposes the injection of harmonic currents into the bus of interest. The great originality of the proposal is that the current injection procedure is not used to get harmonic impedances, but rather to obtain directly the sharing of harmonic responsibilities. Thus, the proposition opens the possibility of obtaining harmonic sharing by using a harmonic current generating device, which can even be an active filter. In order to illustrate the application of the proposed methodology, computational simulations of an electrical system with arrangement similar to real complexes are performed. In addition, laboratory tests are performed using a reduced scale configuration. To confirm the effectiveness of the proposed method, the results obtained from the simulations and laboratory tests are compared with those obtained from a classic theory of responsibility sharing. [ABSTRACT FROM AUTHOR]

Summary: Power quality is important for the reliable operation of power grids. Unwanted harmonics cause serious degradation of power quality. This problem is more obvious for distributed generations connected to a microgrid. To solve this issue, this paper proposes an improved voltage and current (VI) compensator to collectively suppress voltage and current harmonics in a three‐phase hybrid fuel cell and photovoltaic grid‐connected inverters using a synchronous reference frame (SRF) based technique in the presence of non‐linear loads. It is shown that the proposed compensator can effectively reduce the harmonic contents in voltage and current without any dependence on offset devices such as active and passive filters. Simulations in MATLAB/Simulink show that the proposed control strategy not only reduces the total harmonic distortion to less than 5% (as per the IEEE 519 standard) but also results in the least total harmonic distortion (THD) as compared to existing techniques. [ABSTRACT FROM AUTHOR]

This paper presents measurements of the changes in phase angle of the harmonic current for a domestic costumer due to the introduction of energy-efficient lamps (compact fluorescent lamps and light-emitting diodes lamps). Those results are then compared with the aggregation rules according to standard IEC 61000-3-6 and with a mathematical model, in order to highlight the importance of using phase angles in the harmonic estimations. The paper presents both the emission from individual household devices and the variations in the complex harmonic current from a group of devices. Cancellation because of phase-angle difference plays an important role in the emission from a group of different devices. This explains why the increase in emission after changing to energy-efficient lamps is much smaller than expected. Some other power-quality parameters are also considered such as total harmonic distortion, total power factor, and displacement power factor. It is concluded that the complex plane presentation is a useful tool to estimate the harmonic emission from a group of domestic appliances. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Most of the modern home appliances use power electronic circuits as a power supply to interface with the distribution grid. They have become a major source of harmonic distortions in power distribution systems. This article presents a study of the harmonic current characteristics of such appliance through a measurement-based comparative approach. Magnitude-related indices are introduced to compare the harmonic effects of the various appliances and to quantify their relative severity. Phase angle-related indices are introduced to study the diversity of the current harmonics phase angle among the devices and to understand its effect on harmonic cancellation. The proposed approach can be used to establish a database of harmonic characteristics for home appliances and other small, distributed harmonic-producing loads. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Summary: In the context of the electric power quality, there is not a definitive consensus about the theme sharing of responsibility concerning harmonic distortions. This paper presents a new methodological proposal, based on capacitors switching, which contributes effectively to the scientific breakthroughs needed to close this challenging issue. Following a discussion of the physical concepts that make up the basis of the method, its performance is investigated through two case studies. At first, the tests for the application of the proposed procedure were performed by means of computer simulations, which involved a large‐scale electric system. After this step, laboratory tests were carried out in a setup that maintained a structure very close to that simulated, however, on a reduced scale. In both situations, the results found indicated the consistency of the proposed method, which, due to its robustness and simplicity, has great potential in terms of its application to power systems. [ABSTRACT FROM AUTHOR]