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Medellín, Colombia

This article describes the implementation of the multi-objective evolutionary algorithm Pareto front (SPEA) for the planning of distribution system expansion, taking as target functions the investment costs and the number of Sag voltages expected per year. The algorithm is implemented by applying it to real distribution system, given some fixed system parameters such as the number of network segments, number of nodes and the number of initial population. Other variables that are proper of evolutionary algorithms such as percentage of generation population that crosses another (cross) and mutation are taken into consideration. It is concluded that the implementation of SPEA for planning real distribution systems is a good and efficient computational tool when it is necessary to consider several objective functions.

Montoya Ramirez R.D.,University of Medellin | Cuervo F.I.,University of Medellin | Monsalve Rico C.A.,Empresas Publicas de Medellin
Renewable Energy | Year: 2016

This work presents an assessment of the potential use of hydrokinetic turbines in the discharge channels of large hydroelectric power plants in Colombia. The assessment is performed at a pre-feasibility stage in order to evaluate the technical and financial potential of using hydrokinetic devices as a way to exploit kinetic energy in such channels. As a case study, two large hydropower plants were selected, one operated by a Francis turbine and the other operated by a Pelton turbine. The analysis assessed the hydraulic characteristics of the channels and the corresponding discharge flows. A prefeasibility financial analysis in an environment of uncertainty was also carried out using Monte Carlo simulation. The results show that the technology is not currently feasible for the Colombian market conditions, but the situation should be monitored in order to identify the right time for its optimal use in the future. The proposed methodology can be applied to research the feasibility of hydrokinetic energy for other kinds of applications. © 2016 Elsevier Ltd

Agudelo P.A.,Empresas Publicas de Medellin | Hoyos C.D.,Georgia Institute of Technology | Curry J.A.,Georgia Institute of Technology | Webster P.J.,Georgia Institute of Technology
Climate Dynamics | Year: 2011

About 50-60% of Atlantic tropical cyclones (TCs) including nearly 85% of intense hurricanes have their origins as African Easterly Waves (AEWs). However, predicting the likelihood of AEW intensification remains a difficult task. We have developed a Bayesian diagnostic methodology to understand genesis of North Atlantic TCs spawned by AEWs through the examination of the characteristics of the AEW itself together with the large-scale environment, resulting in a probabilistic discrimination between large-scale environments associated with intensifying and decaying AEWs. The methodology is based on a new objective and automatic AEW tracking scheme used for the period 1980 to 2001 based on spatio-temporally Fourier-filtered relative vorticity and meridional winds at different levels and outgoing long wave radiation. Using the AEW and Hurricane Best Track Files (HURDAT) data sets, probability density functions of environmental variables that discriminate between AEWs that decay, become TCs or become major hurricanes are determined. Results indicate that the initial amplitude of the AEWs is a major determinant for TC genesis, and that TC genesis risk increases when the wave enters an environment characterized by pre-existing large-scale convergence and moist convection. For the prediction of genesis, the most useful variables are column integrated heating, vertical velocity and specific humidity, and a combined form of divergence and vertical velocity and SST. It is also found that the state of the large-scale environment modulates the annual cycle and interannual variability of the AEW intensification efficiency. © 2010 Springer-Verlag.

Garcia C.,Empresas Publicas de Medellin | Garcia E.,University of Antioquia | Villada F.,University of Antioquia
Informacion Tecnologica | Year: 2012

The optimization of the expansion planning of the real distribution system in the city of Medellin in Colombia, is analyzed in this work. The distribution system has 155 nodes and 154 branches at a voltage level of 13200 volts. Efficient evolutionary algorithms are applied, with the purpose of observing their improvements and performance when compared with conventional evolutionary algorithms. Besides, a mono-stage and mono-objective distribution planning model, which objective function is the optimization of construction costs and technical losses of the system is also studied. Finally, the impact of specially designed efficient operators for optimization is discussed and the estimated costs are analyzed.

A review on the most common species of grasses and forages in Colombia to determine their potential use as lignocellulosic materials for the production of fuels like bioethanol and biobutanol is presented. For this, location, production yield per hectare and per year, lignocellulosic composition and ethanol yield are considered as main characteristics for determining their potential use. As result, elephant grass and king grass, are presented as the most appropriate ones for their exploration in biofuel production processes with green forages yields per acre per year between 360 and 400 ton and between 240 and 360 ton, respectively. Furthermore based in its cellulose and hemicellulose concentration, theoretical ethanol yields of 466,9 L/dry ton of elephant grass and 449,7 L/dry ton of king grass are obtained.

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