A virtual power plant model for time-driven power flow calculations

This paper presents the implementation of a custom-made virtual power plant model in OpenDSS. The goal is to develop a model adequate for time-driven power flow calculations in distribution systems. The virtual power plant is modeled as the aggregation of renewable generation and energy storage connected to the distribution system through an inverter. The implemented operation mode allows the virtual power plant to act as a single dispatchable generation unit. The case studies presented in the paper demonstrate that the model behaves according to the specified control algorithm and show how it can be incorporated into the solution scheme of a general parallel genetic algorithm in order to obtain the optimal day-ahead dispatch. Simulation results exhibit a clear benefit from the deployment of a virtual power plant when compared to distributed generation based only on renewable intermittent generation.Peer ReviewedPostprint (published version

Reliability analysis of distribution systems with photovoltaic generation using a power flow simulator and a parallel Monte Carlo approach

This paper presents a Monte Carlo approach for reliability assessment of distribution systems with distributed generation using parallel computing. The calculations are carried out with a royalty-free power flow simulator, OpenDSS (Open Distribution System Simulator). The procedure has been implemented in an environment in which OpenDSS is driven from MATLAB. The test system is an overhead distribution system represented by means of a three-phase model that includes protective devices. The paper details the implemented procedure, which can be applied to systems with or without distributed generation, includes an illustrative case study and summarizes the results derived from the analysis of the test system during one year. The goal is to evaluate the test system performance considering different scenarios with different level of system automation and reconfiguration, and assess the impact that distributed photovoltaic generation can have on that performance. Several reliability indices, including those related to the impact of distributed generation, are obtained for every scenario.Postprint (published version

A Solid State Transformer model for power flow calculations

This paper presents the implementation of a Solid State Transformer (SST) model in OpenDSS. The goal is to develop a SST model that could be useful for assessing the impact that the replacement of the conventional iron-and-copper transformer with the SST can have on the distribution system performance. Test distribution systems of different characteristics and size have been simulated during different time periods. The simulations have been carried out assuming voltage-dependent loads and considering that power flow through either the HV/MV substation transformer or any of the MV/LV distribution transformers can be bidirectional. Simulation results prove that a positive impact should be expected on voltages at both MV and LV levels, but the efficiency of current SST designs should be improved.Postprint (author's final draft

Localización óptima de generación distribuida en sistemas de distribución trifásicos con carga variable en el tiempo utilizando el método de Monte Carlo

En el presente trabajo se desarrolla un método para determinar la localización óptima de un generador distribuido que inyecta únicamente potencia activa en un alimentador radial con carga uniformemente distribuida. El algoritmo desarrollado se basa en el método de Monte Carlo y permite obtener los valores óptimos de potencia y posición del generador. El algoritmo también sirve para determinar la localización óptima de bancos de condensadores con el objetivo de obtener una reducción óptima de las pérdidas

Allocation of Distributed Generation for Maximum Reduction of Energy Losses in Distribution Systems

The analysis of actual distribution systems with penetration of distributed generation requires powerful tools with capabilities that until very recently were not available in distribution software tools; for instance, probabilistic and time mode simulations. This chapter presents the application of parallel computing to the allocation of distributed generation for maximum reduction of energy losses in distribution system when the system is evaluated during a given period (e.g., the target is to minimize energy losses for periods equal or longer than 1 year). The simulations have been carried out using OpenDSS, a freely available software tool for distribution system studies, when it is driven as a COM DLL from MATLAB using a multicore installation. The chapter details a MATLAB–OpenDSS procedure for allocation of photovoltaic (PV) generation in distribution systems using a parallel Monte Carlo approach and assuming that loads are voltage‐dependent. The main goals are to check the viability of a Monte Carlo method in some studies for which parallel computing can be advantageously applied and propose a simple procedure for minimization of energy losses in distribution systems

A review of tools, models and techniques for long-term assessment of distribution systems using OpenDSS and parallel computing

Many distribution system studies require long-term evaluations (e.g. for one year or more): Energy loss minimization, reliability assessment, or optimal rating of distributed energy resources should be based on long-term simulations of the distribution system. This paper summarizes the work carried out by the authors to perform long-term studies of large distribution systems using an OpenDSS-MATLAB environment and parallel computing. The paper details the tools, models, and procedures used by the authors in optimal allocation of distributed resources, reliability assessment of distribution systems with and without distributed generation, optimal rating of energy storage systems, or impact analysis of the solid state transformer. Since in most cases, the developed procedures were implemented for application in a multicore installation, a summary of capabilities required for parallel computing applications is also included. The approaches chosen for carrying out those studies used the traditional Monte Carlo method, clustering techniques or genetic algorithms. Custom-made models for application with OpenDSS were required in some studies: A summary of the characteristics of those models and their implementation are also included.Peer ReviewedPostprint (published version

Composici?n Y Estructura De La Comunidad Fitoperif?tica De La Cuenca Del R?o Alvarado, Tolima Colombia

129 P?ginasEl fitoperifiton es importante para la estructura y funcionamiento de los ecosistemas l?ticos debido a su contribuci?n a la producci?n primaria, lo cual lo posiciona de manera importante ya que son de inter?s ecol?gico por los patrones de distribuci?n como respuesta a las condiciones ambientales. Durante este estudio se evalu? la composici?n y estructura de la comunidad fitoperif?tica en la cuenca del r?o Alvarado (Tolima) y su posible relaci?n con algunas caracter?sticas fisicoqu?micas del r?o, durante dos muestreos (septiembre y diciembre) en periodos clim?ticos contrastantes. Se muestrearon nueve estaciones ubicadas a lo largo del r?o Alvarado y sus principales tributarios. En cada punto de muestreo se realizaron dos raspados de la superficie correspondiente al ?rea de un portaobjetos (0,093 m2), en los sustratos naturales (roca y tronco), mediante el uso de cepillos pl?sticos. El fitoperifiton colectado estuvo representado por seis phyllum, nueve clases, 26 ?rdenes, 35 familias y 43 g?neros. Los g?neros m?s representativos en t?rminos de densidad relativa fueron Navicula (24,52%), Fragilaria (11,89%), Nitzschia (8,92%) y Cocconeis (7,80%). La clase Bacillariophyceae fue la de mayor distribuci?n altitudinal desde 351 a 1057 m, mientras que la clase Ulvophyceae se encontr? restringida a los 697 m. Las localidades con mayor diversidad y riqueza fueron r?o Alvarado-Puente (H?= 2,562; = 0,1; Mg=2,8?2) y quebrada Chumba (H?= 2,304; = 0,14; Mg= 2,468), mientras que quebrada Chembe (H?= 1,928; = 0,21; Mg= 1,719) y r?o Alvarado-Caldas Viejo (H?= 1,735; = 0,3035; Mg= 1,63), registraron los valores m?s bajos. A nivel temporal, el periodo de septiembre (altas precipitaciones) report? las mayores densidades (58,93%), y valores altos de diversidad y riqueza (H?= 2,767; Mg= 4,156), as? mismo, el sustrato tronco present? el mayor valor de diversidad y riqueza (H?=2723; Mg=4,139). Seg?n el an?lisis de correspondencia can?nica, las variables fisicoqu?micas que determinaron de manera significativa en el ensamblaje de la comunidad algal en esta cuenca, especialmente sobre los g?neros Nitzschia, Gomphonema y Synedra fueron, en su orden, s?lidos totales, dureza, conductividad el?ctrica, pH y alcalinidad, las cuales influyeron de manera significativa en la distribuci?n en la comunidad fitoperifitica en la cuenca del r?o Alvarado y sus tributarios.SUMMARY The phytoperiphyton is important for the structure and functioning of aquatic ecosystems because of their contribution to primary production, which positions it an important way since ecological interest are the distribution patterns in response to environmental conditions. The composition and structure of the community phytoperiphytic Alvarado river basin (Tolima) and its possible relation to some physico-chemical characteristics of the river for two surveys (September and December) in contrasting climatic periods were evaluated. Nine stations along the Alvarado river and its major tributaries were sampled. At each sampling point two were made scrapings corresponding to a storage area (0.093 m2), on the natural substrates (rock and wood), by using brushes plastic surface. The collected periphyton was represented by six phyllum, nine classes, 26 orders, 35 families and 43 genera. The most representative genres in terms of relative density were Navicula (24.52%), Fragilaria (11.89%), Nitzschia (8.92%) and Cocconeis (7.80%). The Bacillariophyceae class was the most altitudinal distribution from 351-1057 m, while the Ulvophyceae class was limited to 697 m. Localities with greater diversity and richness was river Alvarado-Puente (H '= 2.562, = 0.1, Mg = 2,8?2) and creek Chumba (H' = 2.304, = 0.14, Mg = 2.468), while creek Chembe (H '= 1.928, = 0.21, Mg = 1,71?) and river Alvarado-Caldas-Viejo (H' = 1.735, = 0.3035, Mg = 1.63) recorded the lowest values. In a temporal level, the period from September reported the highest densities (58.93%) and high values of richness and diversity (H '= 2.767, Mg = 4,156), likewise, the substrate stem had the highest value of diversity and richness (H '= 2723; Mg = 4,139). The physicochemical variables that significantly determined the algal community in this watershed, especially the genera Nitzschia, and Synedra, Gomphonema were, in order, total solids, hardness, electrical conductivity, pH and alkalinity, which significantly influenced the distribution in the community fitoperifitica of the Alvarado river basin and its tributaries.INTRODUCCI?N 18 1. OBJETIVOS 20 1.1. OBJETIVO GENERAL 20 1.2. OBJETIVOS ESPEC?FICOS 20 2. MARCO REFERENCIAL 21 2.1. ANTECEDENTES 21 2.2. MARCO CONCEPTUAL 31 2.2.1. Generalidades del perifiton.. 31 2.2.2. Organizaci?n taxon?mica. 32 2.2.3. Importancia del perifiton como indicador de la calidad del agua. 33 3. MATERIALES Y M?TODOS 34 3.1. METODOLOG?A DE CAMPO 34 3.2. PAR?METROS FISICOQU?MICOS Y BACTERIOL?GICOS 37 3.3. PROCESAMIENTO DE LAS MUESTRAS EN EL LABORATORIO 37 3.4. AN?LISIS DE DATOS 38 3.4.1. Densidad relativa.. 38 3.4.2. ?ndices Ecol?gicos 39 3.4.3. An?lisis de variables fisicoqu?micas. 40 3.4.4. An?lisis de Correspondencia. 40 4. RESULTADOS 41 4.1. VARIABLES BIOL?GICAS 41 4.1.1. Composici?n General 41 4.1.2. Muestreo 1. Septiembre de 2012 (Altas precipitaciones) 45 4.1.3. Muestreo 2: Diciembre de 2012 (Bajas precipitaciones) 51 4.1.4. MICROH?BITAT DE ALGAS PERIF?TICAS 56 4.2. ?NDICES ECOL?GICOS 59 4.2.1. ?ndices de diversidad a nivel general (Septiembre y Diciembre) 59 4.2.2. ?ndices de diversidad por estaciones 60 4.2.3. ?ndices de diversidad a nivel de sustratos 61 4.2.4. ?ndices de diversidad a nivel temporal 62 4.2.5. ?ndices de diversidad de sustratos a nivel temporal 64 4.2.6. ?ndices de diversidad de sustratos por estaci?n a nivel temporal 66 4.3. VARIABLES FISICOQU?MICAS Y BACTERIOL?GICAS 69 4.3.1. ANOVA de Kruskal-Wallis 70 4.3.2. AN?LISIS DE COMPONENTES PRINCIPALES (ACP) 74 4.3.3. AN?LISIS DE CORRESPONDENCIA CAN?NICA ENTRE VARIABLES FISICOQU?MICAS Y LA COMUNIDAD FITOPERIFITICA DE LA CUENCA DEL R?O ALVARADO 82 5. DISCUSI?N 87 5.1. VARIABLES BIOL?GICAS 87 5.2. ?NDICES ECOL?GICOS 90 5.3. VARIABLES FISICOQU?MICAS Y BACTERIOL?GICAS 92 6. CONCLUSIONES 95 7. RECOMENDACIONES 97 REFERENCIAS 98 ANEXOS 11

Construcción de cónicas por medio de papiroflexia

Este documento es un resumen del taller denominado "construcción de cónicas por medio de papiroflexia" el cual es una actividad que tiene como objetivo introducir a los docentes del área de matemáticas al uso de la papiroflexia y ejemplificar su utilidad en los salones de clases como un recurso didáctico sencillo y práctico. Además es una exhortación a investigar y experimentar con metodologías innovadoras en el momento de planificar actividades relacionadas a la introducción de un concepto nuevo o la definición de una regla o procedimiento matemático, esto con el afán de lograr en los dicentes, más que memorización de un algoritmo, desarrollar un concepto o procedimiento matemático coherente, con significado y en relación con sus conocimientos previos