bluuebunny/crossref_metadata_2025 huggingface dataset:
Estudio sobre un relieve identificado recientemente como huasteco
Authors: Gutiérrez Solana Nelly
Published: April 2017

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Signos glíficos relacionados con Tláloc en murales de la batalla de Cacaxtla
Authors: Foncerrada de Molina Marta
Published: April 2017

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Retablos salomónicos en Puebla
Authors: Díaz Marco
Published: April 2017

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La experimentación en el arte contemporáneo
Authors: Rodríguez Prampolini Ida
Published: April 2017

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El espacio de la música
Authors: Estrada Julio
Published: April 2017

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Los dibujos de Orozco para el mural "Omnisciencia"
Authors: Moyssén Xavier
Published: April 2017

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El paisajista Adolfo Tenorio
Authors: García Barragán Elisa
Published: April 2017

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Eros, Thanatos y el mito de Dionisios-Tres sarcófagos de la época severiana
Authors: Del Conde Teresa
Published: April 2017

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Percepción espacio-temporal en la obra de Samuel Beckett y Alberto Giacometti
Authors: Molina Barea María del Carmen
Published: April 2017

El presente artículo plantea un análisis de la percepción espacio-temporal en la producción artística de Samuel Beckett y Alberto Giacometti. Se tomarán como objeto de estudio dos obras concretas: por un lado, el montaje televisivo Quad I & II, de Beckett, y por otro, el texto titulado “El sueño, el Sphinx y la muerte de T.”, escrito por Giacometti. Ambas piezas se abordarán desde el concepto de tiempo de Henri Bergson, la teoría del universo tetradimensional de Hermann Minkowski, y la visión esquizofrénica del espacio-tiempo según Eugène Minkowski.
Los artistas como críticos. Reseñas sobre pintura hechas por artistas plásticos en el Boletín Mensual Carta Blanca, 1934-1939
Authors: Aceves Ávila Roberto
Published: April 2017

Se rescatan ocho artículos de crítica de obras de arte publicados por David Alfaro Siqueiros (sobre Echave el Mozo y Carlos Orozco Romero), Carlos Orozco Romero (sobre Alvise Vivarini), Carlos Mérida (Peeter Jansz Pourbus, el Viejo, Francisco Goitia, Antonio Ruiz y Eugenio Landesio) y Roberto Montenegro (Ovens Juriane). Se publicaron originalmente en el Boletín Mensual Carta Blanca, entre 1935 y 1938 y no se habían reimpreso. Los artículos van precedidos de una breve historia del Boletín, creado por Salvador Novo a instancias de Xavier Villaurrutia, una descripción de sus contenidos, el contexto y las condiciones de su creación. Se señala la contribución del Boletín para divulgar la opinión y la crítica sobre artes visuales y para promover la obra de artistas tanto antiguos como contemporáneos mediante un folleto publicitario de calidad, que contribuyó a la difusión de la cultura en México durante la década de los años treinta del siglo XX.
Cardiometabolic Disease Staging Predicts Effectiveness of Weight-Loss Therapy to Prevent Type 2 Diabetes: Pooled Results From Phase III Clinical Trials Assessing Phentermine/Topiramate Extended Release
Authors: Guo Fangjian , Garvey W. Timothy
Published: April 2017

OBJECTIVE

To assess the ability of medication-assisted weight loss to prevent diabetes as a function of the baseline weighted Cardiometabolic Disease Staging (CMDS) score.

RESEARCH DESIGN AND METHODS

We pooled data from 3,040 overweight and obese participants in three randomized controlled trials—CONQUER, EQUIP, and SEQUEL—assessing efficacy and safety of phentermine/topiramate extended release (ER) for weight loss. In these double-blind phase III trials, overweight/obese adult patients were treated with a lifestyle intervention and randomly assigned to placebo versus once-daily oral phentermine/topiramate ER. The weighted CMDS score was calculated using baseline quantitative clinical data including waist circumference, blood glucose, blood pressure, and blood lipids. Incident diabetes was defined based on serial measures of fasting glucose, 2-h oral glucose tolerance test glucose, and/or HbA1c.

RESULTS

The absolute decrease in 1-year diabetes incidence rates in subjects treated with medication versus placebo was greatest in those with high-risk CMDS scores at baseline (10.43–6.29%), intermediate in those with moderate CMDS risk (4.67–2.37%), and small in the low-risk category (1.51–0.67%). The number of participants needed to treat to prevent one new case of diabetes over a 56-week period was 24, 43, and 120 in those with baseline CMDS scores of ≥60, 30–59, and 0–29, respectively.

CONCLUSIONS

Numbers needed to treat to prevent one case of type 2 diabetes are markedly lower in patients with high-risk scores. CMDS can be used to quantify risk of diabetes in overweight/obese individuals and predict the effectiveness of weight-loss therapy to prevent diabetes.
Numerical analysis of the inlet channel and basin geometries for vortex generation in a gravitational water vortex power plant
Authors: M.J. Perez-Molina  , P. Eguia-Lopez  , M. Larruskain-Eskobal  , A.  Etxegarai-Madina  , S. Apiñaniz Apiñaniz
Published: April 2017

Recently, the utilization of low-head hydroelectric technologies has received a great attention for the expansion of distributed power systems into isolated regions that are difficult to be connected to the electrical grid, especially in developing countries. The use of gravitational vortex hydropower systems can be a renewable and suitable option to expand electricity access and promote development in these remote regions, which are concomitantly rich in hydric resources, due to this system can operate with low head without the need of a large reservoir and installation area. In this study, the performance of the inlet channel and basin of a gravitational water vortex turbine was investigated. Two inlet channels and two basin geometries were numerically analysed in Ansys Fluent software. The velocity and vortex height were calculated and compared for each setting. It was found that the inlet channel with conical basin tended to produce more symmetric vortex in comparisons with that generated by the cylindrical geometry. Additionally, the conical basin maximized the flow velocity on the water surface area.
On meteorological forecasts for energy management and large historical data: A first look
Authors: Cyril Voyant  , Cédric Join  , Michel Fliess  , Marie-Laure Nivet  , Marc Muselli  , Christophe Paoli
Published: April 2017

This communication is devoted to a com-parison between various meteorological forecasts, for the pur-pose of energy management, via different time series tech-niques. The first group of methods necessitates a large num-ber of historical data. The second one does not and is mucheasier to implement, although its performances are todayonly slightly inferior. Theoretical justifications are related tomethods stemming from a new approach to time series, artifi-cial neural networks, computational intelligence and machinelearning. Several numerical simulations are provided and dis-cussed.
Fuzzy Logic Based Maximum Power Point Tracking Using Boost Converter for Solar Photovoltaic System in Kuwait
Authors: Mohamed A. El-Sayed  , Steven Leeb
Published: April 2017

Currently, the production of the rapid increasing electrical energy in Kuwait depends mainly on oil and its derivatives, which result in environmental pollution. Moreover, the export of oil production represents a key income for Kuwait and any saving in its consumption represents an essential concern to land’s economy. Therefore, the power utility and economy of Kuwait will benefit from substituting fossil fuels by clean and renewable energy resources such as solar energy. For efficient utilization of solar energy, the PV panel should track the maximum power point (MPP) under various weather conditions in Kuwait. Most of existing MPP tracking techniques depend mainly on perturb & observe (P&O) or incremental conductance (IC) algorithm using conventional PID controllers. On the other side, fuzzy logic controller (FLC) provides an adaptive nature, fast response, good performance and ability to handle non-linear characteristics. In this paper, the proposed (FLC) substitutes PID controller in P&O and IC (MPPT) under different weather conditions in Kuwait. The obtained results of the proposed (FLC) are compared with conventional PID controller. The performance of the implemented PV panel is validated and the results indicated that FLC has successfully tracked the MPP with minimum voltage oscillations.
VSC- based HVDC System Capability to Ride Through Faults
Authors: O. Abarrategui  , D.M. Larruskain  , I. Zamora  , V. Valverde  , G. Buigues  , A. Iturregi
Published: April 2017

VSC-HVDC is becoming an increasingly attractive technology for power network development. In order to establish itself a viable alternative it still has to address some issues, e.g., its response under fault situations on both AC and DC side. This paper makes a state-of-the-art review on how different converter topologies affect the Fault Ride Through (FRT) ability of the system. By comparing the different converter topologies, it is possible to underline the features that will be able to guarantee a successful FRT, which can be very helpful in order to choose the most suitable converter topology for different applications.
Fast Method to the Unit Scheduling of Power Systems with Renewable Power Sources
Authors: G. J. Osório  , J. M. Lujano-Rojas  , J. C. O. Matias  , J. P. S. Catalão
Published: April 2017

Modelling wind power uncertainty is a critic aspect in the optimal management of power systems with high integration of this renewable resource. It is typically carried out by considering a limited number of representative scenarios that incorporate relevant properties such as hourly auto-correlation and diurnal forecasting profile. Considering a large amount of scenarios improves the wind power modelling, but increases the computational effort. To deal with this problem, a method to incorporate a big set of scenarios in stochastic unit commitment (UC) problem is presented in this paper. The effectiveness of the proposed methodology is evaluated by means of the analysis of a case study and the results are compared to those obtained from a stochastic programming method, concluding that the method presented in this paper offers an approximated solution in a reduced computational time.
Sustainable Energy System of El Hierro Island
Authors: R. Godina  , E. M. G. Rodrigues  , J. C. O. Matias  , J. P. S. Catalão
Published: April 2017

Isolated islanded energy systems do not have any connection to continental grids and nor do have an easy access to conventional energy sources. In order to face this specific challenge, El Hierro project on the small El Hierro island, Canary Islands, was put in practice. This project embodies the first major Megawatt-level energy project by linking energy storage systems with wind power generation using water storage delivered by the pumping system between two artificial lakes. In this paper, we analyse the project and discuss the first results after the inauguration
Use of fractals to improve a proton exchange membrane fuel cell performance
Authors: P. Barbieri  , G. Benetti  , E. Mathias  , M. Klein  , J. Bottin  , M. M. Forte  , P. M. Belchor
Published: April 2017

One of the most important and effective elements in the improvement of efficiency and power density of proton Exchange membrane fuel cells (PEMFC) are the flow field plates. The flow field plate design and its pattern considerably affect the effectiveness of mass transport as well as electrochemical reactions inside the cell. A goal of the flow field plate configuration is to ensure a low pressure drop over all the channels in a cell or over all the cells in a stack. As a result, the aim of this research was use biological inspiration to improve the anode flow hydrogen area without improve the pressure loss in a parallel flow field plate (PFFP), by inserting fractals in a classic PFFP design. The results showed that, fractals can increase the hydrogen flow area without improve the pressure loss and repeat the PFFP fluid dynamic behavior at smaller scales in the same plate.
Comparative of heat transfer performance between a parallel serpentine-baffle flow field plate and a parallel flow field plate design in a direct ethanol proton exchange membrane fuel cell
Authors: G. Benetti  , P. Barbieri  , E. Mathias  , J. Bottim  , M. Klein  , M. M. Forte  , P. M. Belchor
Published: April 2017

The dependence on fossil fuels as an energy source causes serious environmental problems. Direct ethanol proton exchange membrane fuel cells (DE-PEMFCs) that directly convert the chemical energy stored in the etanol alcohol into electricity makes it promising as an environment-friendly power source for portable and mobile applications. Increasing the reagent operating temperature increases the electrochemical kinetics at the anode, increasing the cell power. However in a DE-PEMFC, the flow field plate directly interferes at the heat flow. As a result, the aim of this research were project a new parallel serpentine flow field plate with interdigitated characteristics, a parallel serpentine-baffle flow field plate (PSBFFP) and comparing with a PSFFP with respect to heat transfer performance in a DE-PEMFC anode side. The results show that the discontinue channels presents in the PSBFFP improve the heat transfer between plate and reagent, improving the reaction rate and consequently the fuel cell performance.
Shunt Active Power Filter with Selective Harmonics Compensation for LV distribution grid
Authors: F. Belloni  , R. Chiumeo  , C. Gandolfi
Published: April 2017

A Shunt Active Power Filter (SAPF) employable in a Low Voltage distribution grid four-wires model is presented. The use of this device helps to improve Power Quality compensating harmonic currents, reactive power and current unbalances of a disturbing loads. Each compensating function can be activated or disabled according to the specific requirements of the application. A selective harmonic compensation is also possible, in order to avoid possible resonances at specific frequencies. A current hysteresis modulation with predictive calculation of threshold bands achieving fixed switching frequency is adopted for a fast dynamic response. The compensation performance of the proposed active power filter and the associate control scheme under steady state and transient conditions is demonstrated through digital simulations.
Application of PI-Notch controller in the control of grid side converter to reduce PCC harmonic current for DFIG wind energy system
Authors: Ramon Rodrigues de Souza  , Adson Bezerra Moreir  , Paulo Sergio Nascimento Filho  , Tárcio André dos Santos  Barros  , Ernesto Ruppert Filho
Published: April 2017

This work presents the analysis of harmonic of 5th and 7th orders impacts in the grid voltage in a wind generation system based on DFIG. Therefore, there were simulations of the active and reactive power control of the DFIG using the vector control by orientation of the magnetic stator flux. The results of three simulations are presented. In the first simulation it is presented the analysis of the wind power generation system connected to an electric grid with purely sinusoidal voltage. In the second simulation, the wind generation system is connected to an electric grid with distorted voltage for 5th and 7th harmonic orders. In the third simulation it is shown the results of the reduction of harmonic distortion in the electrical currents at the PCC and at the output of the electronic power converter by applying notch filters in the converter current control loops connected to electrical grid.
Technical and economic feasibility of the use of Solar Thermal Energy in Condominiums with Popular Dwellings
Authors: Moraes-Santos, E.C  , Souza, T. M  , Balestieri, J.A.P
Published: April 2017

The proposed works consists in the research on the electric power consumption in a Brazilian municipality and effective financial economy and demand the power grid with the installation of solar water heating. The field research was conducted with the survey method with questionnaires applied in a sample of 360 households. As a result it was confirmed that 55,28 % of interviewed households has electric power consumption between 151-200 kWh; all of them have electric shower with an average use time 1 hour/day, the use between 18:00 and 21:00 pm, peak time in Brazil. Therefore, the use of solar thermal energy represents a savings of 12,000 kW / ano for the city and reduce demand electricity grid. Research has proven that low-cost solar water heater is viable to be installed.
Conceptual framework for an integrated method to optimise sustainability of engineering systems
Authors: A. del Caño  , M.P. de la Cruz  , J.J. Cartelle  , M. Lara
Published: April 2017

It is necessary to change the current dynamic of growth, to assure that future generations can satisfy their needs. Sustainable development and global sustainability are two concepts that have achieved great importance in almost every sector of activity. There is a wide range of methods and models for sustainability assessment. Nevertheless, it is necessary to go beyond evaluation, looking for sustainability optimisation. In spite of this, little work has been done on the latter field. The authors present here a conceptual proposal for an integrated method to optimise sustainability of engineering systems, based on the MIVES method. For a better understanding of the method, its essential steps for optimising an energy sub-system are summarized (shell-and-tube heat exchanger).
Smart Load Management in Distribution Networks Incorporating Different Load Sectors using PSO
Authors: S.M. El Safty  , Amany El Zonkoly  , Osama Hebala
Published: April 2017

The excess loads nowadays arising in Egypt brings the monitoring and control of the loads to be the most complicated phenomena facing the electricity utility in Egypt. The main objective of this research is to utilize demand side management (DSM) in order to minimize the peak demand within each of residential, commercial and industrial sectors. This research takes into consideration both utility and customer benefits using particle swarm optimization PSO. Load shifting DSM technique is used to schedule controllable devices of different types at various hours of the day bringing the final load curve closer to an objective load curve. Half hourly forecasted load data and half hourly forecasted pool market price and time of day (TOD) tariff are the inputs given to the DSM program. The proposed algorithm is applied to Alexandria power grid and the simulation results show that the proposed DSM technique comprehends reasonable savings to both utility and consumers simultaneously, while reducing the system peak.
Influence of the reliability of short-term electrical power forecasting for a wind farm on the generation cost per MWh. A case study in the Canary Islands
Authors: Ulises Portero  , Sergio Velázquez  , María Miranda
Published: April 2017

The generation cost of a wind farm has generally been studied on the basis of two factors: the initial investment cost and the operating and maintenance cost. The problems caused in an electrical system by deviations between the actual electrical power generated by a wind farm and the electrical power estimated by prediction models need to be corrected. These deviations result in an additional economic cost. This paper evaluates the deviation cost per unit of energy generated by wind farms and analyses the contribution of this cost to the total production cost. The study undertaken in this paper has been made specific to the Canary Islands (Spain). It can be deduced from the results of the study that the deviation cost can amount to between 1.5% and 15.5% of the cost of producing electrical energy generated by a wind farm depending, amongst other parameters, on the error made in the prediction. Wind farms that are otherwise deemed profitable may not be considered so if the deviation cost is taken into account.
The impact of photovoltaic systems on power losses and voltage profiles in a real medium voltage distribution network
Authors: Nevena Srećković  , Gorazd Štumberger
Published: April 2017

Higher penetration of distributed generation units (DG) into the distribution network (DN) has imminent influence on DN’s power quality and system losses. With DG units being properly placed and sized, numerous positive effects on DN can be achieved. This paper focuses specifically on influence of active and reactive power generation from photovoltaic (PV) systems on voltage profiles and power losses in DN. Main goal of the paper is to evaluate, if power injections from installed PV systems can contribute to the power loss reduction. A case study on realistic model of medium voltage part of DN in town Maribor has been performed. Sizing and suitable location for PV systems that can be installed in the future has been obtained by assessment of buildings’ roof photovoltaic potential. The results presented in the paper show that proper power injections can help reducing power losses in the discussed DN.
Trends in electricity prices and their relation to the competitiveness and efficiency in EU countries
Authors: A. Martínez  , S. Valero  , E. Velasco  , C. Senabre
Published: April 2017

Europe  is  emerging  from  a  deep  financial  and  economic  crisis and   it   is   widely   agreed   that   stronger   European   industrial competitiveness is  vital as  a driver for economic growth and job creation.   In   this   regard,   while   ensuring   the   achievement   of essential   climate   and   environmental   objectives,   it   is   now recognised that it is imperative to ensure that EU energy Union is shaped in such a way to guarantee, not only security of supply for all  consumers,  but  also  stable  and  affordable  energy  prices  for European businesses.
This  article  offers  the  opportunity  to  analyse, all  the  crucial  and sensitive   components   of   the   prices   of   energy   in   some   UE countries:   economic,   financial   and   technological   conditions required to develop renewable energy and other domestic energy resources  in  order  to  reduce  European  dependence  on  third-country  suppliers;  development  of  infrastructure  and  internal  as well   as   cross-border   interconnections;   overhaul   of   national practices  on  energy  levies,  tax  components  of  energy  prices  and network  costs;  moderation  of  energy  demand  and  increase  of energy efficiency.
Characterization of current switching transients for appliance identification
Authors: Yulieth Jimenez  , Cesar Duarte  , Johann Petit  , Jan Meyer  , Peter Schegner  , Gilberto Carrillo
Published: April 2017

Demand Side Management is a key concept within the Smart Grid vision to promote energy efficiency, load flexibility and interaction between the consumers and other power grid stakeholders. Disaggregated information requires an advanced load monitoring system of individual appliance consumption. A smart house is envisioned to include a Nonintrusive Load Monitoring (NILM) system to support demand side management and motivate the users to adopt energy saving practices. NILM systems use input electrical measurements taken at the energy meter point of a house and estimate the individual appliance operation and consumption through mathematical algorithms. Each appliance can be distinguished from others through a set of particular attributes namely load signatures that can be computed from transient signals, steady state signals or both. This paper aims to characterize current switching transients, for NILM applications and to discuss how they are affected by variation of factors such as point on wave of switching, network impedance, supply voltage distortion and sampling frequency of the meter. For that purpose, measurements of residential appliances of several categories are acquired and processed. The conclusion of this work is the assessment of suitability, robustness and efficiency of appliance identification based on current transients.
A Concept to Increase the Bulk Warm Water Production of Ordinary Direct and Indirect Solar-Thermal Systems in Rural India
Authors: D. Norta  , C. Winkler  , Adoni-Team
Published: April 2017

This paper focusses on the application of modified solar-thermal water-preheating systems used during the cooking process in large institutions in rural India. The goal is to reduce the fuel consumption. As a second step a concept is presented to promote the solution among wider group of people by providing a webpage to calculate the cost benefit analysis for potential users online. The presented solar thermal system was installed in cooperation with regional partners and “Engineers Without Borders India” in 2012 in Adoni in central Andhra Pradesh after a project site exploration in 2011. The system is still in operation and delivers hot water.
A Comparative Performance Analysis between Saturated Core Voltage Regulators Using Silicon Steel and Amorphous Alloys
Authors: C. S. Chaves  , J. C. Oliveira  , J. A. F. Barbosa Jr
Published: April 2017

The focus of the paper presented herein is directedtowards the investigative study of the operational performance of saturated  reactors  intended  for  voltage  regulation,  which  consist of magnetic silicon steel cores and amorphous alloys. In order to reach  the  defined  goal,  two  similar  devices  in  terms  of  voltage operation  and  reactive  power  compensation  are  employed,  both embodied  with  a  twin-tripler  or  12  pulse  configuration.  Both devices are modelled and implemented onto the ATP simulator to carry  out  comparative  studies.  Through  the  use  of  a classicdistribution feeder, performance studies   concerning   sudden voltage  variations are considered,  which  are  focused  on  above all:   evaluation   of   active   losses,   non-saturated and   saturated reactive power, waveforms for inductive current and voltage with their  harmonic  spectra.  The  results  obtained  from  the  studies allows   for   a   prompt   correlation   between   the   characteristics associated  with the  functionality  of  the  device,  highlighting  the advantages offered by the use of one or other magnetic material.
Dynamic Behavior of Three phase Inductions Motors as Loads in an Electric Power System with Distributed Generation, a Case of Study
Authors: Marcelo Rodrigo García Saquicela  , Ernesto Ruppert Filho,  , José Luis Azcue Puma
Published: April 2017

One of the basics characteristics of a power electric system is guarantee the power supply to the loads reliable and uninterrupted, the modern power systems have minimal conditions for proper operation, one of studies of major concern is stability. The studies most considering the electric power system as a whole, taking into account elements that affect their behavior, mainly including the dynamic model of the loads. Within industrial environments loads are formed by three phase induction motors, these loads must be modeled dynamically in detail to be possible a faithful study of the system and its real influence into the power system. Will be made dynamic tests into am industrial electric power system selected to verify the influence of induction motor loads, the motors also are controlled with DTC technique and the system can operate with internal generation.
Step Size Selection for Tap Changers in Converter Transformers for Line Commutated HVDC Systems
Authors: K. Roggenkamp  , C. Hahn  , V. Hussennether  , A. Chaudhry  , M. Luther
Published: April 2017

This paper deals with the tap changer design for line-commutated HVDC converter transformers. It examines the impacts of tap changer switching to provide criteria for selecting an optimal step size. When switching the tap changer the firing angles in the converter change and with them the reactive power consumption. The dependence of the changes on the step size of the tap-changer is linear, so that a maximum step size of the tap changer can be calculated based on criteria for maximum allowable changes of firing angle and reactive power. For implementation into an existing AC system the analysis of tap changer switching has to consider the interaction between converter reactive power and AC voltage iteratively to derive a stable operating point of the HVDC after switching. Both effects are influenced by the reaction of the AC-voltage.
The energy saving effect of incorporating an ATRIUM into a building
Authors: R. Getino-De la Mano  , Dr. J. L. Falagán Cavero  , E. Getino Grande
Published: April 2017

The member states of the European Union have set a 2020 target to  reduce  energy  consumption  by  20%  relative  to  figures  for 1990.  In  2011,  the  total  energy  consumption  of  the  building  and installation   sector   in   Spain   was   299,558   gigawatt   hours, accounting for 29.9% of the total national consumption for other uses of 1,000,720 gigawatt hours [1].  
Directive  2010/31/EU  of  the  European  Parliament  and  of  the Council  of  May  19th,  2010,  on  the  energy  performance  of buildings,    establishes    the    objective    of    promoting    energy efficiency    in    buildings    located    in    the    EU,    through    the consideration   of   factors  such   as  outdoor   climatic   and   local conditions  as  well  as  indoor  climate  requirements  and  cost-effectiveness in heating costs.
 This article, based on data collected during a 12 month study of a real building, shows that an energy saving heating and cooling of 19.62% can be achieved through the incorporation into buildings of atrium-style open spaces with energy functions.
Modeling and Simulation of Renewables for Telelabs
Authors: P. Kolhe  , B. Bitzer
Published: April 2017

Increased growth in population and development activities result in increased energy consumption. Environment friendly renewable energy technologies should be promoted to meet this rising energy demand. On the background of this knowledge, research in the field of renewable Hybrid Power System (HPS) is significant. Along with simulation, familiarity with operation and control of physical HPS is equally important. The automation lab of Soest university currently works on a laboratory model of HPS consisting of photovoltaic (PV) panel, wind turbine, battery storage and inverter. In this paper, the concept of Telelab is used to demonstrate modeling of PV panel using Matlab software. Use of HOMER software for modeling and optimization is discussed. The results will be analysed and subsequently conclusion would be discussed. In this paper, the idea of Telelab/Remote lab and its role in knowledge and technology transfer at affordable costs would be discussed at the end. The author would discuss the idea of resource sharing (software and hardware) through the concept of Telelab. The basic architecture of Telelab through which remote authorized users would be able to share the simulation environment and the lab experiment would be described.
A Survey on Innovative Solutions and Projects for the Integration of Renewable Generation in Weak Power Grids
Authors: J.I. San Martin  , P. Eguia  , A. Etxegarai  , E. Torres  , I. Albizu
Published: April 2017

This paper deals with the most relevant issues about the integration of renewable generation in weak power grids. Initially, the main parameters that characterize these types of networks are reviewed, in terms of short circuit power, system inertia and frequency and voltage characteristics. Afterwards, improvement measures in the structure of weak power grids are proposed, analyzing different storage technologies in order to guarantee a high efficiency and reliability of the power system. Finally, the paper reviews the most prominent projects developed worldwide which include the integration of renewable energy in weak grids.
Analysis of Energy Saving and Efficiency Action Plan 2008-2012 in Spain for the Residential Sector (Heating, Appliances and Lighting)
Authors: Yolanda Fernández Ribaya,  , Antonio José Gutiérrez Trashorras  , José Pablo Paredes Sánchez  , Jorge Xiberta  Bernat
Published: April 2017

Energy efficiency is considered one of the most cost effective ways to enhance security of energy supply and reduce greenhouse gas emissions. According to Europe’s Energy Efficiency Plan, the biggest energy saving potential in the EU lies in the built environment. Spanish authorities, aiming to guarantee the energy supply and also to abide with the environmental restrictions, have established the National Energy Efficiency Action Plans (NEEAP), the 2008-2012 Plan is the first one and the 2011-2020 Plan lends continuity. In this paper, we will analyze the measurements proposed by the 2008-2012 Plan for home thermal systems (heating and domestic hot water) and home electric systems (light and appliances). Three scenarios are established to quantify approximately the energy saving for Spanish dewellings in 2012. This paper evaluates, using data currently available, the saving to the year 2012 and compares it with the official Plan results presented. The results show the actual margins of improvement and the success or failure of the Plan measures.
Multi frequency wideband active damping device for compensation of torsional vibration
Authors: M. Stubbe  , N. Ell  , D. Turschner  , H.-P. Beck
Published: April 2017

In this paper a device for wideband, multi frequency active vibration cancellation for rotating drive trains is presented. It can be installed subsequently into problematic drive trains (e.g. wind turbines, combined heat and power stations …) and can be individually fit to the constructive limits given by the existing system. A formula to calculate the mechanical properties of the actuator is derived. Furthermore we present a new electrical design with improved performance and better control possibilities. Based on the new design we show a method for an easy but nevertheless robust control mechanism of the actuator using an asymmetric three phase current system. Finally we present a functional demonstration of the new control algorithm in simulation and give a brief outlook on upcoming research activities.
Control of a Power Generation System Based on a Dual Star Induction Generator
Authors: Renewable energy  , K. NOUNOU  , M. BENBOUZID  , B. TABBACHE  , H. ALLOUI
Published: April 2017

This paper presents a control scheme of a power generation system based on a dual star squirrel-cage induction machine operating as an induction generator. The operating mode based on an excitation control scheme is chosen to ensure a controlled magnitude and frequency of the generator output voltage. Some preliminary simulation and experimental test results, carried out on a prototype of dual star induction machine operating as generator and supplying various loads under different conditions, are presented and discussed.
Investment Analysis for Energy Efficiency Management Systems in Industrial Refrigeration
Authors: T. T. Portela  , J. M. S Lafay
Published: April 2017

Brazil has one of the least efficient industries in energy use when compared to other major world economies. Although it is among the largest producers of poultry in the world, the country has lost competitiveness. The pursuit of energy efficiency is in the Brazilian government plans, while it hasn't occurred effectively. This paper seeks to elucidate the requirements for creating an energy management system for the chicken slaughterhouse industry through a methodology to analyse the feasibility of implementing such system. This industry, in general, has not developed processes for energy management even after the rise of ISO 50001 in 2011. Presumably due to infeasibility to the creation of these systems. The country needs to invest in policies that promote energy efficiency, by proving the viability of investments such as energy monitoring systems or, for example, intervening in the industry through incentives.
Energy Efficiency in Brazil: Policies, Motivators, Barriers
Authors: T.T. Portela  , J. M. S Lafay
Published: April 2017

This paper discusses energy efficiency in thermal processes of chicken slaughterhouses in Brazil, as they are large consumers of electricity and have few indicators to system monitoring. The article reviews energy efficiency in Brazil’s industry, global policies, motivations and barriers to the adoption of an energy management system in the refrigeration circuit. The government lack of regulations towards the development of energy efficiency in the industry, also, that is not the concern of industries managers. That industry is losing competitiveness, as well, the country has an energy inefficient industry. This work compares the production indicator commonly monitored by the chicken slaughterhouses: the Unit Cost which indicates that a slaughterhouse consumes 218.33% of energy in relation to another chicken slaughterhouse. It represents the energy consumed per kilogram of chicken processed, thus the second slaughterhouse uses more than the double of energy to produce the same amount of product. Thus, the disclosure of information for energy efficiency comparison may help the national industry to become more efficient and competitive.
Capacitorless DC-DC Regulator as a Candidate Topology for Photovoltaic Solar Facilities
Authors: Herminio Martínez-García
Published: April 2017

Linear-assisted   DC/DC   converters   (or   linear-switching  hybrid  DC/DC  converters)  consist  of  a  voltage  linear  regulator (classic NPN or nMOS topologies and LDO) connected in  parallel  with  a  switching  DC/DC  converter.  They  are  a  good  candidate for energy processing in photovoltaic solar facilities. In order to control these hybrid structures, different strategies exist, allowing  fixing  the  switching  frequency  as  a  function  of  some  parameters  of  the  linear  regulator.  This  article  compares  two  control  strategies  that,  although  can  be  applied  to  the  same  circuital   structure   of   linear-assisted   converter,   are   sensibly   different.  The  first  one,  reported  in  previous  literature,  cancels  completely  the  average  current  through  the  linear  regulator  in  steady  state  to  achieve  a  reduction  of  the  losses.  Thus  the  efficiency  of  the  whole  system  increases  and  almost  equals  the  one   of   the   standalone   switching   converter.   The   proposed   approach,  in  spite  of  a  slightly  increment  of  linear  regulator’s  losses, reduces the output ripple due to the crossover distortion of linear regulator output stage.
Review of Technical Requirements for Brazilian Distributions Companies for the Integration of Distributed Generators - A Comparative Analysis on the Perspective of IEEE-Std 1547-2
Authors: J.R.C de Almeida  , M.J.B.B. Davi  , C. B. dos Santos  , F. A. M. Moura  , J. R. Camacho
Published: April 2017

The connection of distributed generators, also known as independent generators or independent producers in the distribution systems of medium voltage or low voltage, has been widely encouraged. However, this connection lacks clear and effective regulations regarding access to technical requirements for electrical systems techniques to ensure excellence in distribution systems. Thus, this work presents a comparative analysis between the regulations of national distributors for connecting distributed generators in low and medium voltage systems, weaving a comparative analysis with IEEE 1547-2 standard (IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems).
A Contribution of a Computer Tool Using ATP-EMTP TACS to the Modeling of a Photovoltaic (PV) Module
Authors: C. B. dos Santos  , J. R. C. de Almeida  , M. J. B. B. Davi  , F. A. M. Moura  , J. R. Camacho
Published: April 2017

The access to electrical distribution systems with the use of solar photovoltaic's is becoming a viable alternative for the provision of generation through alternative sources of electricity. However, many studies of power quality and transient stability need to be made to meet the technical requirements of the network. Therefore, this article deals with the modeling of photovoltaic module in ATP-EMTP tool called TACS for future studies of the insertion of the PV system in medium and low voltage. To validate this model comparisons of the simulations with the data provided by the manufacturer, thus validating the developed model were performed.
A system for visualization of power-quality and optimization of the charging behavior for electric vehicles
Authors: Y. Wang  , B. Schwake  , B. Fischer  , P. Stroganov
Published: April 2017

Optimization of the dynamic behavior of the charging process for electric vehicles requires a centralized adjustment of control parameters. The development of suitable algorithms for the adjustment needs a tool to analyze and to visualize measured data from the environment of the charger. In this paper, we present that Power-Quality Map, a system to collect data and to show them on a map, which offers methods for analyzing those measured data. This paper describes the structure of the system, the software architecture and the functionality to visualize maps.
Requirements for Fault Protection in HVDC Grids
Authors: D.M. Larruskain  , O. Abarrategui  , I. Zamora  , G. Buigues  , V. Valverde  , A. Iturregi
Published: April 2017

Conventional Voltage Source Converters (VSC) cannot interrupt DC fault currents and DC circuit breakers are not yet commercially available for HVDC power ratings. Thus, the protection of VSC-HVDC systems is still an obstacle for the development of this technology. The features of VSC-HVDC systems make them suitable for implementing HVDC grids. Nevertheless, HVDC grids are more complex than point-to-point links. Accordingly, the fault protection of these HVDC grids is a bigger challenge due to the specific requirements of DC grids. Nowadays there is no real HVDC grid operating, but it is expected that in the near future HVDC grids will be widespread, reinforcing the predominant AC systems. In this paper, the protection required by HVDC grids is thoroughly analyzed.
Wind power prediction for onshore wind farms using neural networks
Authors: Bogusław Świątek  , Mateusz Dutka
Published: April 2017

This paper describes some of the problems in the prediction of onshore wind farm. The possibility of using a neural network to forecast wind power production and its resistance to changing weather-terrain conditions are examined here. The effect of uneven distribution of the wind speed and direction depending on the location of the turbine are also analyzed. Three different structures of neural networks together with a comparison of efficiency of obtained forecasts are shown.
Photovoltaic Maximum Power Point Grid Connected based on Power Conditioning Technique Employing Fuzzy Controller
Authors: M. Bakkar  , M. Abdel-Geliel  , M. Abo zied
Published: April 2017

Most of the Maximum Power Point Tracking (MPPT) techniques for Photovoltaic (PV) system utilize the PV voltage and current measurements. An MPPT technique for grid connected PV system, which does not require PV measurements, is proposed and implemented. This approach utilizes post-stage inverter current instead of calculating solar array power. This approach is called Power Conditioning System (PCS). PCS requires a searching engine to track the Maximum Power Point (MPP) of the PV system. Fuzzy logic is one of the most powerful MPPT engines, which has high performance and robustness. Therefore, Fuzzy Logic Control (FLC) method is implemented and compared with the other methods. Moreover a proposed method that combines FLC with PCS is designed and tested. In addition, the PCS employing an adaptive fuzzy controller is also designed in order to enhance system performance and robustness. To compare between classical MPPT techniques and the proposed techniques, simulations of overall system using different MPPT techniques are performed. The simulation results are analysed. Moreover, Practical implementation is carried out to validate the simulation results.
Feasible methods to evaluate voltage dips origin
Authors: R. Chiumeo  , L. Garbero  , F. Malegori  , L. Tenti
Published: April 2017

The aim of the work is to compare the advantages and disadvantages of two feasible methods of evaluation of voltage dips “origin” intended as the network where the “fault” has probably occurred. The first method, mainly based on the simultaneous monitoring of an event by nearby primary substations connected to a common high voltage network, has been extensively applied since 2009 to the QuEEN (Quality of the Electric Energy) monitoring system data, by RSE within its research activity. The second one requests the monitoring of both primary substation medium voltage bus-bars and has been proposed as a possible method for the new on-going Italian national monitoring system, developed by the Italian DSOs, by a technical committee on National Monitoring. This method, which has been shared as a possible and feasible method by all the participants to the committee (DSOs, TSO, researchers and the Italian regulator), can be applied at a few QuEEN substations compliant with its requirements. The first method requires the knowledge of the high voltage network topology and, when applied at research level, requires time-expending visual analysis of voltage dips waveforms to compensate the lack of “confidential” information. The second method has lower effectiveness but, being a local method, can be applied also to networks including only one substation.
Testing new ensemble forecasts of solar irradiance
Authors: J.M. Botana  , A. Rodríguez,  , J.A. Gonzalez
Published: April 2017

The increment of solar energy production requires an accurate estimation of surface solar irradiance. A forecast of surface solar irradiance allows estimate the energy production, i.e., to minimize the fluctuations in the electric grid supply. In this work a numerical weather forecast model provides surface solar radiation estimations over a coastal region with changeable weather and typically partially cloudy days. As direct model output over specific locations is not always accurate, an ensemble forecast with four members (including time and spatial combinations) is proposed and validated against measurements from three different weather stations in that region, along 1-year. From this validation, statistics show that the best forecast is achieved with the ensemble member obtained by the linear combination of the solar radiation forecasted for the corresponding time (H), one hour before (H-1), and one hour after (H+1). No improvement is obtained by spatial solar radiation combinations. Also, this ensemble forecast provides an estimation of the solar radiation uncertainty, which can be useful to provide flexible energy production forecasts.
Use of Generic Dynamic Models for Photovoltaic Plants
Authors: P. Eguia  , A. Etxegarai  , E. Torres  , J.I. San Martín  , I. Albizu
Published: April 2017

Electricity production using photovoltaic systems is reaching such a high level in many countries that the system operators are introducing new connection requirements. To evaluate the fulfillment of these requirements, validated simulation models are needed. These models are evolving from manufacturer’s user models to generic models as the ones proposed by the Western Electricity Coordinating Council (WECC). This paper discusses the need for generic models, introduces the photovoltaic plant model developed by WECC and presents a case of generic model parameterization, based on data from a commercial three-phase inverter, and model validation, by comparing simulation results with factory test data.
Using Constant Switching Frequency Control in Linear-Assisted DC-DC Switching Convertersfor Photovoltaic Solar Regulators
Authors: Herminio Martínez-García
Published: April 2017

This article shows the proposal of a linear–assisted converter or linear–&–switching hybrid converter with a constant switching frequency for photovoltaic solar DC-DC regulators. The control loop of the system is based on the current–mode technique. The main disadvantage of a converter with current– mode control is the inherent instability of the loop when switch duty ratios are greater than 0.5. In order to make stable the proposed linear–assisted converter, the article shows the technique based on a slope compensation.