Plug-in Electric Vehicles (PEVs) are progressively penetrating world markets. A significant impact on harmonic distortion in distribution networks is expected due to large-scale charging of PEVs at homes. Therefore, models that accurately predict the individual current injections are needed to perform harmonic studies, in particular frequency domain models such as those based on Frequency Coupling Matrices (FCM). In this paper, Fourier descriptors are used to estimate and compare the FCMs of a commercially available on-board PEV charger. Two models were calculated for two different supply reference conditions, namely, a sinusoidal voltage with no distortion, and a flat-top voltage. To that end, extensive laboratory measurements were carried out. Results show similar values in the parameterized admittances for both reference conditions. These results indicate a wide linear range in the coupled Norton model for this load, and should be probably attributable to the active power factor correction topology of the charger.

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The use of Fourier descriptors (FD) for the assessment of frequency coupling matrices (FCM) of power electronic devices is considered. After some recalls on FDs, FCM approach is discussed showing how the matrices elements can be built basing on the use of maximum two FDs under linearity hypothesis. Then, a non-linearity index that allows to check the validity of the assumed "linearity hypothesis" and to quantify the obtainable accuracy is introduced. Numerical simulations on two very simple non linear circuits are performed to show the sensitivity of the FCM elements to magnitude and phase angle variation of the background harmonic distortion using FDs and the usefulness and the behavior of the non linearity index.

Harmonics in power systems are responsible for several technical problems that justify the development of models to study them. Well-established models exist to analyse the harmonic load-flow (HLF) from a deterministic point of view. Moreover, models based on the probability theory have been developed to deal with the inherent variability and random nature of loads, network configuration etc. In the last few years, possibility theory has arisen as an alternative tool that in many cases could be better suited to describe and quantify the real nature of the uncertainty involved in harmonic studies. In this study a methodology for HLF calculation based on the possibility theory is presented. Possibility distributions instead of probabilities are the input used to describe the uncertainty in the magnitude and composition of the loads. Tests presented shows that the results of the proposed model are consistent with those obtained with a probabilistic method, and that both models lead to the same ranking of the risk that the bus harmonic voltages exceed a given level. Independent possibility distributions are assumed at the development stage reported here; research is being carried out in order to overcome this constraint.

Harmonic distortion in residential distribution networks is increasing due to the penetration of multiple nonlinear loads, including modern technologies such as plug-in electric vehicles and energy efficient lighting (e.g., compact fluorescent and LED lamps). The distributed nature of these loads introduces complexity in the analysis of harmonic propagation. Therefore, more sophisticated tools are needed to investigate this issue, on the basis of formerly established methodologies. This paper presents a literature review on the assessment of the harmonic distortion in residential distribution networks. To that end, bibliographic data of the most representative publications related to the topic were obtained. From these data, a novel citation analysis method was developed to construct a chronologically organized direct citation network. Based on the temporal evolution of the citation network, the aforementioned issue is presented, identifying lines of research and proposed methodologies. From the analysis of the literature review, the stages for modeling and simulating harmonic propagation are identified and described. The principal aspects to be addressed for obtaining an accurate harmonic analysis are also identified and detailed, namely, harmonic interaction, diversity, unbalance, and uncertainty. Finally, main conclusions are highlighted.Keywords: Electric power system, harmonic distortion, power quality, systematic review. RESUMENLa distorsión armónica en redes de distribución está aumentando debido a la penetración de múltiples cargas no lineales, incluyendo tecnologías modernas como los vehículos eléctricos y las lámparas de alta eficiencia energética (por ejemplo, lámparas compactas fluorescentes y LEDs). La naturaleza distribuida de estas cargas introduce complejidad en el análisis de la propagación de armónicos. Por lo tanto, se necesitan herramientas más sofisticadas para investigar esta temática, sobre la base de metodologías establecidas. Este artículo presenta una revisión literaria sobre la evaluación de la distorsión armónica en las redes de distribución residencial. Para ello, se obtuvieron datos bibliográficos de las publicaciones más representativas relacionadas con el tema. A partir de estos datos, se desarrolló un nuevo método de análisis de citas para construir una red de citas directas, organizada cronológicamente. Con base en la evolución temporal de la red, se observan las líneas de investigación y las metodologías propuestas. Además, se identifican las etapas para el modelado y simulación de la propagación de armónicos y se detallan los aspectos para obtener un análisis armónico preciso, a saber, interacción armónica, diversidad, desequilibrio e incertidumbres. Finalmente, se presentan las conclusiones.Palabras clave: Calidad de potencia, distorsión armónica, revisión sistemática, sistema eléctrico de potencia.

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