Análisis del desempeño de un algoritmo Backward/Forward ajustado a una red de distribución con cargas no lineales y un sistema fotovoltaico

Context: The backward/forward (BF) algorithm is a sweep-type technique that has recently been used as a strategy for the power flow analysis of ill-conditioned networks. The purpose of this study is to evaluate the performance of the BF algorithm compared to that of a computational tool such as Simulink, with both strategies adjusted to the operating conditions of a distribution network with nonlinear components (loads and photovoltaic system), unbalanced loads, and harmonic distortion in the voltage and current signals. Method: The study case is a low-voltage distribution network with a radial topology, unbalanced loads, and nonlinear components. The BF algorithm is adjusted to consider two approaches of the Norton model: a coupled admittance matrix and a decoupled admittance matrix. The latter is also used in the network model created in Simulink. The performance of the algorithm is evaluated by analyzing 18 operation scenarios defined according to the presence and use intensity of the loads and solar irradiance levels (low and high). Results: In general, the three strategies could successfully determine the waveform and RMS values of the voltage signals with errors of less than 0,8 and 1,3%, respectively. However, the performance of the strategies for the estimation of current signals and power parameters shows errors of 5-300% depending on the level of solar irradiance at which the photovoltaic system operates. Conclusions: The results show that the BF strategy can be used to analyze unbalanced power grids with increasing penetration of renewable generation and the integration of nonlinear devices, but the performance of this strategy depends on the load model applied to represent the behavior of nonlinear devices and generation systems.Contexto: El algoritmo backward/forward (BF) es una técnica de barrido que se ha utilizado recientemente como estrategia para el análisis de flujo de energía de redes mal acondicionadas. El objetivo de este estudio es evaluar el desempeño del algoritmo BF comparado con el de una herramienta computacional como Simulink, con ambas estrategias ajustadas a las condiciones de operación de una red de distribución con componentes no lineales (cargas y sistema fotovoltaico), desbalance en las cargas y distorsión armónica en tensión y corriente. Método: El caso de estudio es una red de distribución de baja tensión con topología radial, cargas desequilibradas y componentes no lineales. El algoritmo BF se ajusta para considerar dos enfoques del modelo Norton: matriz de admitancia acoplada y matriz de admitancia desacoplada. Este último también se utiliza en el modelo de red creado en Simulink. El desempeño del algoritmo se evalúa mediante el análisis de 18 escenarios de funcionamiento definidos según la presencia e intensidad de uso de las cargas y los niveles de irradiancia solar (baja y alta). Resultados: En general, las tres estrategias podrían determinar con éxito los valores de forma de onda y RMS de las señales de tensión con errores menores de 0,8 y 1,3 % respectivamente. Sin embargo, el desempeño de las estrategias para la estimación de señales de corriente y parámetros de potencia presenta errores de 5-300 % dependiendo del nivel de irradiancia solar en el cual el sistema fotovoltaico se encuentre operando. Conclusiones: Los resultados muestran que la estrategia BF se puede utilizar para analizar redes eléctricas desbalanceadas con creciente penetración de generación renovable e integración de dispositivos no lineales, pero el rendimiento de la misma depende del modelo de carga aplicado para representar el comportamiento de los dispositivos no lineales y de los sistemas de generación

The clinical translation of plastic scintillation dosimetry

Contemporary radiotherapy focuses on achieving the best patient outcomes by delivering highly targeted treatments that often include small fields and high dose gradients. Plastic scintillators outperform traditional dosimeters in these fields as they are close to water-equivalent. However, the translation of scintillation dosimeters into the clinic has been limited by three roadblocks. The generation of Cerenkov radiation in an optic fibre irradiated by megavoltage radiation contaminates the scintillation signal. Two Cerenkov removal methods (spectral discrimination and air core) were found to be accurate in accounting for Cerenkov radiation and their clinical robustness was improved. The light readout system is often the limiting factor for the accuracy of scintillators. PMTs outperform camera-based systems, though their implementation for array dosimetry is complex. A novel system with a multianode PMT was constructed and enabled multiple light signals from an array to be simultaneously measured. Arrays of scintillation dosimeters are difficult to create due to the complex arrangement of detectors and their optical pathways. Two innovative approaches (square waveguides and 3D printing) were used to build prototype scintillation dosimeter arrays. These arrays showed that scintillation dosimeters can measure dose distributions with high spatial and temporal resolution. Addressing these roadblocks has enabled the clinical translation of scintillation dosimeters. In small field dosimetry, an air core dosimeter was used as a reference to calculate and predict correction factors for existing dosimeters. For brachytherapy, an array of scintillators provided real-time dose measurements that improved the safety of the treatment. For rotational treatments, a cylindrical array was used to verify the dose delivered during simulated stereotactic treatments. Traditional dosimeters cannot be used in these applications and this demonstrates the potential of scintillation dosimetry

Desarrollo sostenible en edificaciones

In  this document  two  topics are exposed:  (1) how  the problems of  the energy consumption and of  the polluting emissions  of  the  current  constructions  they  can  be  reduced with  the  concept  green  building,  and  (2)  how  the sustainable  applications,  implemented  in  other  countries,  they  could  generate  fnancial  important  savings  and sustainability during  the use of  the Edifcio Eléctrica 2 of  the Universidad  Industrial de Santander  that  is  in  the process of design due to two factors: the decrease in the electric power demand and the use of the renewable energies in place. The review of the state-of-the-art, has as central aspects: the sustainable development, the exergy concept and the green building. This analysis of the information will allow establish the relevant aspects to take into account in the technical specifcations for the future design of the Edifcio Eléctrica 2. En este documento se exponen dos aspectos: (1) cómo los problemas del consumo de energía y de las emisiones contaminantes  de  las  edificaciones  actuales  pueden  reducirse  desde  el  concepto  green  building,  y  (2)  cómo  las aplicaciones  sostenibles,  implementadas  en  otros  países,  podrían  generar  importantes  ahorros  financieros  y sostenibilidad durante la utilización del Edificio Eléctrica 2 de la Universidad Industrial de Santander que está en proceso de diseño, debido a dos factores: la disminución en la demanda de energía eléctrica y el aprovechamiento de las energías renovables en sitio. La revisión del estado del arte realizada, tiene como aspectos centrales: el desarrollo sostenible, el concepto de la exergía y los green building. Este análisis de la información permitirá establecer los aspectos relevantes a tener en cuenta en las especifcaciones técnicas del futuro diseño del Edificio Eléctrica 2

Desarrollo sostenible en edificaciones

In  this document  two  topics are exposed:  (1) how  the problems of  the energy consumption and of  the polluting emissions  of  the  current  constructions  they  can  be  reduced with  the  concept  green  building,  and  (2)  how  the sustainable  applications,  implemented  in  other  countries,  they  could  generate  fnancial  important  savings  and sustainability during  the use of  the Edifcio Eléctrica 2 of  the Universidad  Industrial de Santander  that  is  in  the process of design due to two factors: the decrease in the electric power demand and the use of the renewable energies in place. The review of the state-of-the-art, has as central aspects: the sustainable development, the exergy concept and the green building. This analysis of the information will allow establish the relevant aspects to take into account in the technical specifcations for the future design of the Edifcio Eléctrica 2. En este documento se exponen dos aspectos: (1) cómo los problemas del consumo de energía y de las emisiones contaminantes  de  las  edificaciones  actuales  pueden  reducirse  desde  el  concepto  green  building,  y  (2)  cómo  las aplicaciones  sostenibles,  implementadas  en  otros  países,  podrían  generar  importantes  ahorros  financieros  y sostenibilidad durante la utilización del Edificio Eléctrica 2 de la Universidad Industrial de Santander que está en proceso de diseño, debido a dos factores: la disminución en la demanda de energía eléctrica y el aprovechamiento de las energías renovables en sitio. La revisión del estado del arte realizada, tiene como aspectos centrales: el desarrollo sostenible, el concepto de la exergía y los green building. Este análisis de la información permitirá establecer los aspectos relevantes a tener en cuenta en las especifcaciones técnicas del futuro diseño del Edificio Eléctrica 2

Comparison of arterial and venous blood biomarker levels in chronic obstructive pulmonary disease

Purpose: The development of novel biomarkers is an unmet need in chronic obstructive pulmonary disease (COPD). Arterial blood comes directly from the lung and venous blood drains capillary beds of the organ or tissue supplied. We hypothesized that there would be a difference in levels of the biomarkers metalloproteinase 9 (MMP-9), vascular endothelial growth factor A (VEGF-A) and interleukin 6 (IL-6) in arterial compared with venous blood. Methods: Radial artery and brachial vein blood samples were taken simultaneously in each of 12 patients with COPD and seven controls with normal lung function. Circulating immunoreactive MMP-9, VEGF-A and IL-6 levels in serum were measured using quantitative enzyme-linked immunosorbent assays. Results were compared using a Student’s paired t test. The study was powered to determine whether significant differences in cytokine levels were present between paired arterial and venous blood samples. Results: In the 12 patients with COPD, four were female, and age ranged 53-85 years, mean age 69 years. Three patients in the control group were female, with age range 46-84 years, mean age 64.7 years. In the COPD group, three patients had mild, five moderate and four severe COPD. No significant difference was found between arterial and venous levels of MMP-9, VEGF-A or IL-6. Conclusions: In this pilot study, levels of the measured biomarkers in arterial compared with venous blood in both COPD patients and healthy controls did not differ. This suggests that as we continue to chase the elusive biomarker in COPD as a potential tool to measure disease activity, we should focus on venous blood for this purpose

Comparison of arterial and venous blood biomarker levels in chronic obstructive pulmonary disease

Purpose: The development of novel biomarkers is an unmet need in chronic obstructive pulmonary disease (COPD). Arterial blood comes directly from the lung and venous blood drains capillary beds of the organ or tissue supplied. We hypothesized that there would be a difference in levels of the biomarkers metalloproteinase 9 (MMP-9), vascular endothelial growth factor A (VEGF-A) and interleukin 6 (IL-6) in arterial compared with venous blood. Methods: Radial artery and brachial vein blood samples were taken simultaneously in each of 12 patients with COPD and seven controls with normal lung function. Circulating immunoreactive MMP-9, VEGF-A and IL-6 levels in serum were measured using quantitative enzyme-linked immunosorbent assays. Results were compared using a Student’s paired t test. The study was powered to determine whether significant differences in cytokine levels were present between paired arterial and venous blood samples. Results: In the 12 patients with COPD, four were female, and age ranged 53-85 years, mean age 69 years. Three patients in the control group were female, with age range 46-84 years, mean age 64.7 years. In the COPD group, three patients had mild, five moderate and four severe COPD. No significant difference was found between arterial and venous levels of MMP-9, VEGF-A or IL-6. Conclusions: In this pilot study, levels of the measured biomarkers in arterial compared with venous blood in both COPD patients and healthy controls did not differ. This suggests that as we continue to chase the elusive biomarker in COPD as a potential tool to measure disease activity, we should focus on venous blood for this purpose

Methodological tool for energy evaluation through simulation of buildings in the tropic

The interpretation of results is a barrier that prevents the use of Building Energy Simulation Tools - BEST in the process of building design. This creates special requirements of experience and knowledge in BEST users, restricting their use to expert professionals. To facilitate that users with low experience can carry out the evaluation of the energy performance of tropical buildings, it was established a methodological tool based on a benchmarking by indicators. As reference values, it was defined Resolution 0549 of 2015 (Colombia) as baseline and ASHRAE 90.1 as the reference building. This tool was applied to evaluate the energy performance of three buildings, two of university type and one residential. The results indicate that the use of this tool aids to improve quality of the results and reduce the time required for analysis.La interpretación de resultados es una barrera que impide el uso frecuente de herramientas de simulación energética -  HSE en el proceso de diseño de edificaciones. Además, crea requerimientos especiales de experiencia y conocimiento en los usuarios de las HSE, restringiendo su uso a profesionales expertos. Para facilitar en los usuarios menos experimentados la evaluación del desempeño energético de edificaciones tropicales se estableció una herramienta metodológica fundamentada en la evaluación comparativa por indicadores.  Como valores de referencia, se adoptaron la línea base de la Resolución 0549 de 2015 (Colombia) y el edificio de referencia de la ASHRAE 90.1. Dicha herramienta permitió evaluar el desempeño energético de tres edificaciones, dos de tipo universitario y una residencial. A partir del uso esta herramienta se logró mejoras en el tiempo y la calidad de los resultados

Determinación de parámetros de métodos de matriz de admitancia acoplada y desacoplada del modelo Equivalente Norton para extractor de aire

Context: Studies carried out in low voltage networks have explored the modeling of linear single-phase loads (such as motors) and non-linear ones (such as those based on power electronics). However, induction motors exhibit non-linear characteristics between voltage and current due to the saturation of their magnetic parts. Therefore, it is necessary to study induction motors in the frequency domain with a model that allows reviewing the characteristic nonlinearity of their voltage-current interaction. Methodology: This article presents the frequency domain modeling of a single-phase induction motor used as a silent air extractor (127 V, 60 Hz, 66 W), which presents a capacitive behavior (fp = 0,93 in leading) and harmonic distortion due to a third-order component (7,0%) when fed with a pure sinusoidal voltage of 127 V. Results: This work establishes the parameters of two approaches to the Norton equivalent model (coupled and decoupled admittance matrix) which are used to estimate the distorted current signal and the values ​​of consumed active and non-active power. The results show comparisons errors of P, Q, THDi, and NRMSE indices of less than 7, 4, 14, and 3%, respectively. Conclusions: The parameters of the Norton equivalent model estimated for the single-phase induction motor allow calculating the current signal with a high degree of precision. This signal exhibits nonlinear characteristics and a capacitive behavior due to the permanent presence of a capacitor aiding the start and operation of the engine.Contexto: Estudios realizados en redes de baja tensión han explorado el modelado de cargas monofásicas lineales (como motores) y no lineales (como dispositivos basados en electrónica de potencia). No obstante, los motores de inducción presentan características no lineales entre tensión y corriente debido a la saturación de sus partes magnéticas. Por ello es necesario estudiar el motor de inducción en el dominio de la frecuencia con un modelo que permita revisar la no linealidad característica de su interacción tensión-corriente. Metodología: Este artículo presenta el modelado en el dominio de la frecuencia de un motor de inducción monofásico usado como extractor de aire silencioso (127 V, 60 Hz, 66 W), el cual presenta un comportamiento capacitivo (fp = 0,93 en adelanto) y distorsión armónica debido a una componente del tercer orden (7,0 %) al ser alimentado con una tensión sinusoidal pura de 127 V. Resultados: Este trabajo establece los parámetros de dos enfoques del modelo equivalente de Norton (matriz de admitancias acoplada y desacoplada) usados para estimar la señal de corriente distorsionada y los valores de potencia activa y no activa consumidas. Los resultados muestran errores de comparación de P, Q, índices THDi y NRMSE menores al 7, 4, 14 y 3% respectivamente. Conclusiones: Los parámetros del modelo equivalente de Norton estimados para el motor de inducción monofásico permiten calcular con un alto grado de precisión la señal de corriente, la cual presenta características no lineales y un comportamiento capacitivo por la presencia permanente de un capacitor que ayuda al arranque y funcionamiento del motor

Performance Analysis of a Backward/Forward Algorithm Adjusted to a Distribution Network with Nonlinear Loads and a Photovoltaic System

Context: The backward/forward (BF) algorithm is a sweep-type technique that has recently been used as a strategy for the power flow analysis of ill-conditioned networks. The purpose of this study is to evaluate the performance of the BF algorithm compared to that of a computational tool such as Simulink, with both strategies adjusted to the operating conditions of a distribution network with nonlinear components (loads and photovoltaic system), unbalanced loads, and harmonic distortion in the voltage and current signals. Method: The study case is a low-voltage distribution network with a radial topology, unbalanced loads, and nonlinear components. The BF algorithm is adjusted to consider two approaches of the Norton model: a coupled admittance matrix and a decoupled admittance matrix. The latter is also used in the network model created in Simulink. The performance of the algorithm is evaluated by analyzing 18 operation scenarios defined according to the presence and use intensity of the loads and solar irradiance levels (low and high). Results: In general, the three strategies could successfully determine the waveform and RMS values of the voltage signals with errors of less than 0,8 and 1,3%, respectively. However, the performance of the strategies for the estimation of current signals and power parameters shows errors of 5-300% depending on the level of solar irradiance at which the photovoltaic system operates. Conclusions: The results show that the BF strategy can be used to analyze unbalanced power grids with increasing penetration of renewable generation and the integration of nonlinear devices, but the performance of this strategy depends on the load model applied to represent the behavior of nonlinear devices and generation systems

INSTALACIÓN DE UN SISTEMA FOTOVOLTAICO EN EL EDIFICIO DE INGENIERÍA ELÉCTRICA DE LA UNIVERSIDAD INDUSTRIAL DE SANTANDER

La instalación de un sistema fotovoltaico del Edificio de Ingeniería Eléctrica de la Universidad Industrial de Santander, se llevó a cabo atendiendo la necesidad de una transición energética hacia sistemas de generación de energía eléctrica con fuentes no convencionales de energía renovable; por lo anterior, en la terraza superior del Edificio se cuenta con 37 paneles fotovoltaicos para una capacidad instalada total de 9,63 kW. El sistema fotovoltaico se diseñó para ser un laboratorio vivo, con lo cual, la instalación permite monitorizar los paneles FV de forma individual para investigar comportamiento térmico, interacción con horticultura y techos verdes, entre otros. Además, se contó con la instalación de medidores inteligentes en el sistema fotovoltaico, capaces de registrar y medir en tiempo real hasta 300 variables eléctricas