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El presente trabajo propone una metodología para realizar un estudio técnico del impacto sobre la calidad de la potencia de la red eléctrica interna de la Universidad de Nariño (Red eléctrica de prueba) al momento de masificar sistemas fotovoltaicos conectados directamente a red. Dicha metodología es aplicada en cuatro escenarios de prueba, en los cuales se desarrollan procesos de cosimulación entre DigSilent/PowerFactory y Matlab/Simulink para evaluar parámetros importantes como: niveles de tensión, cargabilidad en conductores y transformadores, pérdidas totales, comportamiento del factor de potencia y contribuciones a la corriente de corto circuito a medida que el nivel de penetración de sistemas fotovoltaicos aumenta en la red propuesta. Dentro de las simulaciones desarrolladas, se utilizan datos reales de variables atmosféricas y eléctricas para modelar un sistema fotovoltaico conectado a red que permite replicar la operación dentro de la red eléctrica y determinar los impactos producidos al masificar este tipo sistemas. Los resultados en simulación darán indicadores importantes para determinar el máximo nivel de penetración fotovoltaica permitido en la red propuesta, además de plantear recomendaciones generales para mitigar las posibles consecuencias al momento de planear futuros proyectos fotovoltaicos al interior del campus universitario Abstract: The present work proposes a methodology to perform a technical study over power quality impacts into the University of Nariño’s internal electrical grid (Electrical test grid) when the grid connected photovoltaic systems are massified. This methodology is applied in four test scenarios to develop cosimulation process between DigSilent/PowerFactory and Matlab/Simulink. With this simulation, important parameters like voltage levels, loading in conductors and transformers, total losses, behavior of the power factor and contributions to the short-circuit current are evaluated at the moment of the penetration level of photovoltaic systems increases in the proposed grid. By developing these simulations, we used real data of atmospheric and electrical variables to model a connected photovoltaic system. That allow a replication of the operation within the electrical grid and determine the impacts when this type of photovoltaic systems are highly used. The simulation results is going to give the main indicators to determine the maximum level of photovoltaic penetration into the electrical grid proposal. In addition, it will present general recommendations to mitigate the possible consequences when future photovoltaic projects inside the university campus are development Maestría

The insertion of photovoltaic solar energy has increased considerably over the past few years, with remarkable growth since 2005. It is essential that the electrical energy delivered by the photovoltaic system to the grid has an acceptable quality level. This paper presents test results of power factor and harmonic distortion content in grid connected inverters for photovoltaic systems. Several tests of ten commercially available inverter models from three different manufacturers were performed at the Laboratory of Solar Energy (Labsol) at the Federal University of Rio Grande do Sul (UFRGS), using a test bench with a power analyzer. The power factor and total harmonic distortion in current curves were mathematically modeled as a function of relative power in order to be used in computer simulation of photovoltaic systems. For power loads close to the nominal values, the harmonic content was found to be low and in accordance with the standard requirements. Nevertheless, at low loading levels the inverters may inject high levels of harmonics into the grid.

The amount and quality of the energy converted by a photovoltaic system connected to the grid can be evaluated by experimental monitoring or computer simulation. The Solar Energy Laboratory at UFRGS developed a simulation software for analysis of grid connected photovoltaic systems (FVCONECT). In order to perform a reliable simulation, it is required for the implementation of suitable mathematical models that describe the behavior of each system component. The inverter is the equipment responsible for converting DC to AC. The manufacturers provide some technical parameters for the inverters. However, electrical and thermal characteristics require mathematical models which coefficients must be obtained from specific tests. This work presents a methodology for analysis of thermal behavior of inverters. Such analysis requires experimental determination of two thermal coefficients. Energy losses due to inverters overheating can be calculated through the proposed methodology, providing a more accurate simulation of a determined photovoltaic (PV) system. The proposed methodology has been tested in several inverters, providing good results.

This paper presents a methodology associated to a set of explicit equations aimed to translate point-to-point the generated power to standard test conditions and its application to a real situation. Such equations are employed for monitoring and diagnostic of grid connected photovoltaic systems. The proposed method is based in the data analysis through statistical methods and it allows diagnosis or detection of instant decreases of generated power. The Experimental results are compared with other procedure of characterization of the nominal power of large photovoltaic generators under real operation conditions which are based on protocols similar to the one proposed in this paper. Results show differences less to 3% between both methods. In conclusion, the methodology presented is useful for real time diagnose of power decrease, when variation of maximum power with temperature is not known or in cases where catalog parameters are not available.

This article presents the development of a test bench for the characterization of batteries for solar uses as well as results of tests conducted using solar batteries. The test bench comprises three main blocks: the thermal module, the power supply and the measuring module. The thermal module consists of a thermally regulated bath with a heating and cooling system capable of maintaining a constant working temperature with an accuracy of ± 0.3 °C. The power supply is a bipolar Kepco, BOP 36-12D that allows charging and discharging of batteries with a control unit that allows its automatic operation. Finally, the measuring system comprises a set of sensors and circuits with the capability of logging battery voltage, charge / discharge current, density and temperature. All these variables are measured with an error lower than that specified by the standard IEC 61427 - 2005. Gathered data are transmitted to a PC where they are recorded and displayed in real time. The software supports various charge / discharge profiles with different values of the current, the bath temperature and test duration hence allowing the possibility of cyclic testing. The test bench developed is currently the first of its kind in the country with the capability to comply with standards as to the characterization of solar batteries is concerned.

No presente trabalho é feita uma descrição e análise dos componentes principais que constituem os sistemas fotovoltaicos autónomos e ligados à rede. Foram também sistematizados os passos que, no seu conjunto, constituem uma metodologia adequada para efectuar o dimensionamento de ambos os tipos de sistemas fotovoltaicos. Com base na metodologia identificada foi desenvolvida uma aplicação computacional em linguagem Hypertext Preprocessor (PHP) para a Internet, a qual foi utilizada em dois casos de estudo: Dimensionamento de um sistema fotovoltaico autónomo e de um sistema fotovoltaico ligado à rede. In this work, the main components of photovoltaic systems both stand alone and grid connected, are described and analysed. It was also presented the sequence of the main tasks, which constitutes a methodology suitable to carry out the sizing procedure of both stand-alone and grid connected photovoltaic systems. Based on this methodology, a computational application was developed under Hypertext Preprocessor (PHP) language for the Internet, which was used on two study cases: Sizing of a stand-alone photovoltaic system and grid connected photovoltaic system.