The use of computational fluid dynamics to study furnace effects in ITS-90 fixed points realizations

Together with the impurities, the thermal fluxes are one of the major sources of uncertainty during the realization of the International Temperature Scale of 1990 (ITS-90) defining fixed points. The use of computational fluid dynamics (CFD) is a valuable tool to develop models that describe the time evolution of the phase transformation (essentially the evolution of the solid–liquid interface) as a function of given theoretical assumptions and given parameters (furnace thermal gradients, freezing initiation, ambient temperature and insulation). The models can be validated by observing the impact of the selected parameters on the observed corresponding melting curves and used to achieve a full understanding of these thermal effects and their impact on uncertainty. This paper proposes an ITS-90 metallic fixed points CFD model together with some results about the influence of the furnace thermal gradients and the freezing initiation techniques.This research is included in the EMRP Joint Research Project SIB10 NOTED, jointly funded by the EMRP participating countries within EURAMET and the European Unio

Infrared temperature measurement sensors of overhead power conductors

Efficiency in power lines operation is becoming more crucial as the electrification increases and more renewable energies are connected into the grid. New methods and sensors are being added to create smart grids to face these challenges and conductor temperature sensors are one of them. Contact temperature sensors have several problems regarding safety and electronic damage due to the electromagnetic fields induced on the conductors. The goal of this paper is to describe an infrared temperature measurement sensor and to compare contact and non-contact temperatura measurements to estimate the temperature of power lines. Measurements were done for almost a year, storing around 150,000 measures of contact and infrared thermometers for many different weather and load conditions. The results conclude that the infrared system can be successfully used to control the temperature of the overhead conductor within a range of less than 4 _C difference with respect to contact temperature methods for the 88% of the samples and less than 6 _C for the 99%.This research was funded by the EU Regional Development Fund (FEDER) and the Spanish Government under the R+D initiative INNPACTO with reference IPT-2011-1447-920000, ENE-2013-42720-R and RETOS-COLABORACION RTC-2015-3795-3

Thermal-fluid characterization of alternative liquids of power transformers: a numerical approach

The transformers lifespan depends importantly on its refrigeration. Mineral oils perform this work in the majority of the power transformers. However, this type of coolant has two main drawbacks: low biodegradability and low ignition point. Several alternative liquids are being developed in order to overcome these drawbacks. This paper compares their thermal-fluid behavior with a mineral oil by means of several parameters, such as temperature, flow rate, fluids velocity, convective heat transfer coefficient (h) and the cooling criterion (P). These are calculated using the numerical results of the simulation of a 3D-model of a Low Voltage Winding that belongs to a power transformer with ONAN cooling. The software COMSOL Multiphysics has allowed the simulation of the geometry using a physical model in which buoyancies and viscous forces are the only considered establishing the natural convection. As a result of the comparison, it is clear that the mineral oil is the best coolant liquid. Among the alternative liquids, silicone oil would be the second best coolant fluid, followed by the synthetic and natural esters, respectively. On the other hand, it seems to be clear that the 3D simulations can be used to compare properly the cooling capacities of the liquids.The research leading to these results has received funding from multiple sources during years but we would specifically like to acknowledge the support received in the later stages from the Spanish Plan Estatal de I+D under the grant agreement DPI2013-43897-P

Comparison between IEEE and CIGRE thermal behaviour standards and measured temperature on a 132-kV overhead power line

This paper presents the steady and dynamic thermal balances of an overhead power line proposed by CIGRE (Technical Brochure 601, 2014) and IEEE (Std.738, 2012) standards. The estimated temperatures calculated by the standards are compared with the averaged conductor temperature obtained every 8 min during a year. The conductor is a LA 280 Hawk type, used in a 132-kV overhead line. The steady and dynamic state comparison shows that the number of cases with deviations to conductor temperatures higher than 5 ∘ C decreases from around 20% to 15% when the dynamic analysis is used. As some of the most critical variables are magnitude and direction of the wind speed, ambient temperature and solar radiation, their influence on the conductor temperature is studied. Both standards give similar results with slight differences due to the different way to calculate the solar radiation and convection. Considering the wind, both standards provide better results for the estimated conductor temperature as the wind speed increases and the angle with the line is closer to 90 ∘ . In addition, if the theoretical radiation is replaced by that measured with the pyranometer, the number of samples with deviations higher than 5 ∘ C is reduced from around 15% to 5%This work was supported by the Spanish Government under the R+D initiative INNPACTO with reference IPT-2011-1447-920000 and Spanish R+D initiative with reference ENE2013-42720-R. The authors would also like to acknowledge Viesgo for its support

Machine learning‐assisted high‐throughput SERS classification of cell secretomes

During the response to different stress conditions, damaged cells react in multiple ways, including the release of a diverse cocktail of metabolites. Moreover, secretomes from dying cells can contribute to the effectiveness of anticancer therapies and can be exploited as predictive biomarkers. The nature of the stress and the resulting intracellular responses are key determinants of the secretome composition, but monitoring such processes remains technically arduous. Hence, there is growing interest in developing tools for noninvasive secretome screening. In this regard, it has been previously shown that the relative concentrations of relevant metabolites can be traced by surface-enhanced Raman scattering (SERS), thereby allowing label-free biofluid interrogation. However, conventional SERS approaches are insufficient to tackle the requirements imposed by high-throughput modalities, namely fast data acquisition and automatized analysis. Therefore, machine learning methods were implemented to identify cell secretome variations while extracting standard features for cell death classification. To this end, ad hoc microfluidic chips were devised, to readily conduct SERS measurements through a prototype relying on capillary pumps made of filter paper, which eventually would function as the SERS substrates. The developed strategy may pave the way toward a faster implementation of SERS into cell secretome classification, which can be extended even to laboratories lacking highly specialized facilities.Universidade de Vigo/CISUGAgencia Estatal de Investigación | Ref. PID2019-108787RB-I0

Analysis of a real case of ampacity management in a 132 kV network integrating high rates of wind energy

The grid integration of renewable energy, and particularly in Spain, supposes an important problem to deal with for Distributor System Operators (DSO). Most of the times Wind Energy Farms are located in places that are far away from the transmission networks so they have to be integrated into distribution networks that are frequently next to their static rate. Current regulations make almost impossible to build new overhead lines so the increase of the capacity of the existing lines is a new target for the DSO. One of the developed options to solve this issue is the dynamic management of the network. This paper is devoted to the analysis of a real case of ampacity management in a 132 kV overhead line placed in a high-wind generation area. The obtained results show that this approach can increase the lines capacity in a significant percentage.This work was supported by the Spanish Government under the R+D initiative INNPACTO with reference IPT-2011-1447-920000 and Spanish R+D initiative with reference ENE2013-42720-R. The authors want also to acknowledge E.on Distribution for its support and help

Coidentificación de intervenciones urbano-territoriales

Introducción – Justificación – Procedimiento – Cartografía del proceso – ¿Cómo leer las fichas? – Producto del curso – Sistematización: Resultados por Departamento – Introducción – ¿Cómo leer las fichas? – Resumen general de resultados – Artigas – Canelones – Colonia – Durazno – Maldonado – Paysandú – Río Negro – Rocha – Salto – Tacuarembó – Listado de Propuestas – Comentario final – Estructura Metodológica General – Anexo – Bibliografía

Metodología para el cálculo y predicción de la ampacidad en líneas eléctricas aéreas, según la elección de los emplazamientos críticos

Método para el cálculo y predicción de la ampacidad en líneas eléctricas aéreas, que permite aumentar la capacidad de transporte eléctrico de los cables conductores de las líneas aéreas, y que comprende las etapas de: - seleccionar las líneas más susceptibles de ver aumentada su capacidad de transporte eléctrico; - realizar un estudio microclimático, permitiendo así identificar las zonas de la línea donde se pueda producir menor refrigeración del cable conductor; - disponer en un punto de aquellas zonas obtenidas mediante el estudio microclimático, estaciones meteorológicas y sensores de corriente y temperatura del conductor; - transcurrido al menos un año, realizar los estudios estadísticos tanto de los registros de temperatura del conductor como de: viento efectivo, temperatura ambiente y radiación solar, obteniendo así las secciones críticas; - calcular la ampacidad estimada mediante normativa, y aplicar a dicha ampacidad una corrección debida a la máxima flecha de la línea, y a la aparamenta existente en la línea; - calcular la temperatura superficial en el cable conductor estimada mediante normativa; - medir la temperatura superficial en el cable conductor con al menos un sensor de temperatura; - realizar un estudio de las diferentes correlaciones que existen entre el error en la estimación de la temperatura del conductor y las variables que afectan al cálculo, y obtener las correlaciones más críticas: - calcular la temperatura corregida para cada variable y condición de aplicación; - predecir las variables meteorológicas para el cálculo de la predicción de la ampacidad a corto y medio plazo.Solicitud: 201600022 (29.12.2015)Nº Pub. de Solicitud: ES2569431A1 (10.05.2016)Nº de Patente: ES2569431B1 (23.02.2017

Infrared Temperature Measurement Sensors of Overhead Power Conductors

Efficiency in power lines operation is becoming more crucial as the electrification increases and more renewable energies are connected into the grid. New methods and sensors are being added to create smart grids to face these challenges and conductor temperature sensors are one of them. Contact temperature sensors have several problems regarding safety and electronic damage due to the electromagnetic fields induced on the conductors. The goal of this paper is to describe an infrared temperature measurement sensor and to compare contact and non-contact temperature measurements to estimate the temperature of power lines. Measurements were done for almost a year, storing around 150,000 measures of contact and infrared thermometers for many different weather and load conditions. The results conclude that the infrared system can be successfully used to control the temperature of the overhead conductor within a range of less than 4 ∘C difference with respect to contact temperature methods for the 88% of the samples and less than 6 ∘C for the 99%