In the expansion of power distribution networks, the periodic task of determining the location, number, and capacity of the distribution transformers is still an open issue that needs to be systematically coped with. In this paper, a comprehensive approach for solving in practice the mentioned task is presented. The proposed methodology is based on an improved clustering technique, which considers not only the actual distances between consumers but also their electrical demand. Graph theory is exploited to represent the feasible paths of the complete system, so that, the distances and the obtained locations are accurate, and feasible in practice, respectively. The proposed objective function minimizes the total annual costs of the system, by considering investments, transformer losses, and operational costs. An approximate expression to calculate the maximum distance between each transformer and its furthest customer to accomplish voltage regulation has been obtained. Consequently, the outputs of the proposed model are the correct number of distribution transformers to be installed, their optimal locations and capacities, and the best consumer grouping with acceptable voltage drops. In order to validate the proposal, this methodology is applied to an urban system with 106 consumers, 23 vertexes, and 31 streets with promising results.

Flexibility Value of Distributed Generation in Transmission Expansion Planning | InTechOpen, Published on: 2010-02-01. Authors: Paul Vasquez and Fernando Olsina

La integración de la movilidad eléctrica es una realidad en el mundo actual, las políticas gubernamentales se enfocan cada vez más en incentivar el uso de vehículos eléctricos (VE) particulares, pero, principalmente en reemplazar la movilidad pública convencional por el uso de buses eléctricos. Una adecuada gestión energética de los sistemas de buses eléctricos debe optimizar el uso de recursos, prolongando la vida útil de las unidades de transporte, estaciones de carga y brindando siempre un servicio de calidad a sus usuarios. El desempeño del sistema de transporte mediante VE depende de diversas variables determinísticas y estocásticas que necesitan ser debidamente simuladas a fin de analizar su comportamiento, lo más cercano a las condiciones reales. En el presente trabajo, mediante la aplicación del software SUMO (Simulation of Urban Mobility), se ha implementado un modelo para el análisis energético de VE y se lo ha aplicado en rutas de transporte público en Quito-Ecuador. A partir de las simulaciones realizadas se ha estimado el consumo energético y se ha efectuado un análisis de sensibilidad del consumo energético de las unidades de buses eléctricos ante variaciones de parámetros relevantes en la gestión energética de sistemas de transporte público. Para el caso de estudio se comprueba la reducción de la autonomía del bus eléctrico en 27% de acuerdo con la información del fabricante. El análisis del desempeño energético realizado bajo diversos escenarios de tráfico permitirá en futuros trabajos optimizar la operación de los sistemas de transporte público eléctrico, considerando niveles de tráfico, flujo vehicular variable y pronunciados desniveles en su relieve.

Electric mobility is one of the main pillars of the global energy transition towards a more sustainable and environmentally responsible model. Greenhouse gas emissions could be drastically reduced with electric mobility massification. Public transport systems represent the first step of this massification due to government policies, but these electromobility projects should optimize their resources to be cost-effective. Furthermore, the implementation of charging stations could cause negative impacts on electrical distribution networks, which should be evaluated beforehand for the adequate planning of power grids. A methodology was developed and implemented herein for the technical and economic evaluation of electric bus-based transport systems.