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  • Contributions on corona onset voltage calculation for EHV and UHV substation connectors

     Hernandez Guiteras, Joan
    Universitat Politècnica de Catalunya
    Theses

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    Les investigacions realitzades en aquesta tesi es va realitzar en el marc d'un acord empresa - universitat . L'objectiu d'aquesta investigació és determinar la tensió d'inici de l'efecte corona en geometries no uniformes per evitar la seva aparició, i així poder incidir en la fase de disseny del connectors de subestació de EHV i UHV i equipmanet auxiliar de línia instal·lats en condicions de funcionament, d'acord amb les normes internacionals . Per tant , s'ha prestat una consideració especial a l'estudi i el modelatge de l'efecte corona per assegurar que els connectors dissenyats es trobin gairebé lliures d'aquest efecte indesitjable . Degut a de la natura d'aquest acord marc, la investigació científica s'ha vist delimitada a l'aplicabilitat en un entorn industrial a fi d'obtenir la accreditació, segons les normatives internacionals, dels productes analitzats.Per tant , els temes tractats en aquesta investigació inclouen l'anàlisi de camps electromagnètics i els càlculs de l'efecte corona , sent aquest últim de gran importància en el disseny dels connectors de subestació per EHV i UHV . És objectiu d'aquesta tesi proporcionar augmentar el coneixement i aportar mètodes matemàtics apropiats per avaluar el comportament dielèctric de connectors de subestació per a sistemes de transmissió de EHV i UHV . En concret , s'ha destinat un capítol a la introducció a l'estat de la tècnica en connectors de la subestació i l'efecte corona, seguit d'un capítol adreçat a l'estudi dels camps elèctrics i magnètics creats pels connectors de la subestació i les equacions empíriques per al càlcul de l'effecte corona. A continuació, s'introdueix una descripció macroscòpica del corona a través de la descripció matemàtica del procés de ionització, tant des del cas estacionari com el transitori. Seguit de la descripció microscòpica a través de funcions de distribució estadístiques utilitzdes per descriure i calcular els paràmetres d'ionització del corona en l'aire . Finalment, es troba el capítol de tancament amb les principals aportacions de la investigació realitzada.

  • Tren motriz de alto rendimiento para el vehiculo electrico basado en las últimas tecnologías de motores sincronos y convertidores de potencia de carburo de silicio

     Garcia Espinosa, Antonio; Riba Ruiz, Jordi Roger; Ortega Redondo, Juan Antonio; Moreno Eguilaz, Juan Manuel; Delgado Prieto, Miguel; Romeral Martinez, Jose Luis
    Competitive project

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  • Redesign process of a 765 kV AC substation connector by means of 3D-FEM simulations

     Hernandez Guiteras, Joan; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    Simulation modelling practice and theory
    Vol. 42, p. 1-11
    DOI: 10.1016/j.simpat.2013.12.001
    Date of publication: 2014-03-03
    Journal article

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    This paper shows the capabilities of applying the three-dimensional finite element method (3D-FEM) for designing complex-shaped substation connectors to operate at 765 kVRMS AC. To check this methodology, it was analyzed the feasibility of upgrading a 400 kVRMS substation connector to operate at 765 kVRMS. However, both experimental and simulation results conducted according to the ANSI/NEMA CC 1-2009 standard concluded that although it passed the visual corona test, to ensure a wide safety margin it was desirable an improvement of the electrical behavior of such connector. It was shown that FEM results allowed detecting the peak stress points of the connector regarding the electrical stress thus allowing applying a corrective action. Then, two possible solutions were analyzed, i.e. the use of corona shields and the redesign of the connector assisted by 3D-FEM simulations. Results presented in this work show that both approaches have an excellent behavior in reducing the electric field strength on the connector surface. However, to make the final decision, the production cost of both alternatives was analyzed, thus favoring the redesign option. Next, the redesigned version of the substation connector was manufactured and tested. Experimental results conducted in a high voltage laboratory verified the effectiveness of the methodology and the potential of the proposed system to act as an advanced design tool for optimizing the behavior of complex-shaped substation connectors. Thus, this system allows assisting efficiently the design process while permitting constraining the economic costs

  • Environmental assessment of small-scale production of wood chips as a fuel for residential heating boilers

     Esteban Dalmau, Bernat; Riba Ruiz, Jordi Roger; Baquero Armans, Grau; Puig Vidal, Rita; Rius Carrasco, Antoni
    Renewable energy
    Vol. 62, p. 106-115
    DOI: 10.1016/j.renene.2013.06.041
    Date of publication: 2014-02
    Journal article

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    This work performs a comparative life cycle assessment (LCA) of two fuels for heating boilers, namely wood chips and oil. The LCA methodology allows comparing the environmental impacts of the two analyzed fuels, thus assessing which is environmentally more advantageous. The study is focused on Mediterranean forests located in the Argençola region (Catalonia, northeastern Spain) by applying forest management practices focused to ensure a sustainable exploitation. The direct use of wood chips as a fuel for boilers simplifies notably the number of processes involved in producing such a fuel. The results presented clearly show the environmental benefits of using small-scale produced wood chips instead of fossil oil by analyzing representative impact categories defined by the CML and EDIP methods, even when considering the changes in the carbon stock in the forests under analysis due to the management approach adopted. A sensitivity analysis has also been conducted to assess the impact of the data with higher uncertainty on the final LCA results.

  • Runout tracking in electric motors using self-mixing interferometry

     Atashkhooei, Reza; Urresty Betancourt, Julio; Royo Royo, Santiago; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    IEEE-ASME transactions on mechatronics
    Vol. 19, num. 1, p. 184-190
    DOI: 10.1109/TMECH.2012.2226739
    Date of publication: 2014-01-17
    Journal article

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  • Improved design of an extra-high-voltage expansion substation connector through magnetic field analysis

     Hernandez Guiteras, Joan; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    Simulation modelling practice and theory
    Vol. 43, p. 96-105
    DOI: 10.1016/j.simpat.2014.02.001
    Date of publication: 2014-04
    Journal article

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    In many countries worldwide, the energy demand is growing faster than the transmission capacity. However, due to environmental constrains, social concerns and financial costs, the construction of new power transmission lines is an arduous task. In addition, power transmission systems are often loaded close to their nominal values. Therefore, improving power transmission system efficiency and reliability is a matter of concern. This work deals with a 400 kV, 3000 A, 50 Hz extra-high-voltage expansion substation connector used to connect two substation bus bars of 150 mm diameter each. This substation connector has four aluminum wires which provide the conductive path between both bus bars. Preliminary tests showed an unequal current distribution through the wires which was mainly attributed to the proximity effect. A three-dimensional finite elements method approach was applied to improve the design and evaluate the electromagnetic and thermal behavior of both the original and improved versions of the connector. Experimental tests made under laboratory conditions have validated the accuracy of the simulation method presented in this paper, which may be a valuable tool to assist the design process of substation connectors, therefore allowing improving both the thermal performance and reliability of the redesigned connectors.

  • A simple laboratory experiment to measure the surface tension of a liquid in contact with air

     Riba Ruiz, Jordi Roger; Esteban Dalmau, Bernat
    European journal of physics
    Vol. 35, num. 5
    DOI: 10.1088/0143-0807/35/5/055003
    Date of publication: 2014-06-25
    Journal article

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  • Detection of interturn faults in PMSMs with different winding configuration

     Saavedra Ordoñez, Harold; Urresty Betancourt, Julio; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    Energy conversion and management
    Vol. 79C, p. 534-542
    DOI: 10.1016/j.enconman.2013.12.059
    Date of publication: 2014-03-03
    Journal article

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    Interturn faults in permanent magnet synchronous motors (PMSMs) may develop fast into more severe faults such as coil-to-coil, phase-to-phase and phase-to-ground short circuits. These faults are very destructive and may irreversibly damage the PMSM. Therefore, it is highly desirable to develop suitable methods for the early detection of such faults. The effects of interturn faults are visible in both the stator currents and the zero-sequence voltage component (ZSVC) spectra. By designing appropriate fault diagnosis schemes based on the analysis of the harmonic content of such electric variables it is possible to detect short circuit faults in its early stage. However, the stator winding configuration of the PMSM deeply impacts the harmonic content of both spectra. This paper studies the effects of different stator winding configurations in both the stator currents and the ZSVC spectra of healthy and faulty machines. Results presented may help to develop fault diagnosis schemes based on the acquisition and further analysis of the stator currents and/or the ZSVC harmonic components.

  • Shaft Trajectory Analysis in a Partially Demagnetized Permanent-Magnet Synchronous Motor

     Urresty Betancourt, Julio César; Atashkhooei, Reza; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis; Royo Royo, Santiago
    IEEE transactions on industrial electronics
    Vol. 60, num. 8, p. 3454-3461
    DOI: 10.1109/TIE.2012.2213565
    Date of publication: 2013-08-01
    Journal article

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    Demagnetization faults have a negative impact on the behavior of permanent-magnet synchronous machines, thus reducing their efficiency, generating torque ripple, mechanical vibrations, and acoustic noise, among others. In this paper, the displacement of the shaft trajectory induced by demagnetization faults is studied. It is proved that such faults may increase considerably the amplitude of the rotor displacement. The direct measure of the shaft trajectory is performed by means of a noncontact self-mixing interferometric sensor. In addition, the new harmonics in the back electromotive force (EMF) and the stator current spectrum arising from the shaft displacement are analyzed by means of finite-element method (FEM) simulations and experimental tests. Since conventional finite-element electromagnetic models are unable to predict the harmonics arising from the shaft trajectory displacement, an improved finite-element model which takes into account the measured trajectory has been developed...

    Abstract—Demagnetization faults have a negative impact on the behavior of permanent-magnet synchronous machines, thus reducing their efficiency, generating torque ripple, mechanical vibrations, and acoustic noise, among others. In this paper, the displacement of the shaft trajectory induced by demagnetization faults is studied. It is proved that such faults may increase considerably the amplitude of the rotor displacement. The direct measure of the shaft trajectory is performed by means of a noncontact self-mixing interferometric sensor. In addition, the new harmonics in the back electromotive force (EMF) and the stator current spectrum arising from the shaft displacement are analyzed by means of finite-element method (FEM) simulations and experimental tests. Since conventional finite-element electromagnetic models are unable to predict the harmonics arising from the shaft trajectory displacement, an improved finite-element model which takes into account the measured trajectory has been developed. It is shown that this improved model allows obtaining more accurate back EMF and stator current spectra than those obtained by means of conventional models. This work presents a comprehensive analysis of the effects generated by demagnetization faults, which may be useful to develop improved fault diagnosis schemes

  • A Cumulative Energy Demand indicator (CED), life cycle based, for industrial waste management decision making

     Puig Vidal, Rita; Fullana Palmer, Pere; Baquero Armans, Grau; Riba Ruiz, Jordi Roger; Bala Gala, Alba
    Waste management
    Vol. 33, num. 12, p. 2789-2797
    DOI: 10.1016/j.wasman.2013.08.004
    Date of publication: 2013-12
    Journal article

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    Life cycle thinking is a good approach to be used for environmental decision-support, although the complexity of the Life Cycle Assessment (LCA) studies sometimes prevents their wide use. The purpose of this paper is to show how LCA methodology can be simplified to be more useful for certain applications. In order to improve waste management in Catalonia (Spain), a Cumulative Energy Demand indicator (LCA-based) has been used to obtain four mathematical models to help the government in the decision of preventing or allowing a specific waste from going out of the borders. The conceptual equations and all the subsequent developments and assumptions made to obtain the simplified models are presented. One of the four models is discussed in detail, presenting the final simplified equation to be subsequently used by the government in decision making. The resulting model has been found to be scientifically robust, simple to implement and, above all, fulfilling its purpose: the limitation of waste transport out of Catalonia unless the waste recovery operations are significantly better and justify this transport.

  • Influence of the stator windings configuration in the currents and zero-sequence voltage harmonics in permanent magnet synchronous motors with demagnetization faults

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    IEEE transactions on magnetics
    Vol. 49, num. 8, p. 4885-4893
    DOI: 10.1109/TMAG.2013.2247046
    Date of publication: 2013-08
    Journal article

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    Demagnetization faults in permanent magnet synchronous motors may generate specific fault harmonic frequencies in the stator currents and the zero-sequence voltage component (ZSVC) spectra. Hence, by analyzing the stator currents or/and the ZSVC spectra it is possible to develop fault diagnosis schemes to detect such faults. In order to have a broad view of such effects, a representative set of stator windings configurations must be considered. By analyzing different stator windings configurations this paper shows that the amplitude of the harmonic frequencies of both the stator currents and the ZSVC spectrato be analyzed are significantly influenced by the stator windings configuration. It is also proved that depending on the winding configuration, new harmonic components may emerge in both spectra. The results presented in this paper may help to develop fault diagnosis schemes based on the acquisition and further analysis of the stator currents and the ZSVC harmonic components.

  • Diagnosis of interturn faults in pmsms operating under nonstationary conditions by applying order tracking filtering

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    IEEE transactions on power electronics
    Vol. 28, num. 1, p. 507-515
    DOI: 10.1109/TPEL.2012.2198077
    Date of publication: 2013
    Journal article

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    Interturn faults in permanent magnet synchronous machines may have very harmful effects if not early identified. This study deals with the detection of such faults when the machine operates under varying speed conditions. The performance of two methods is analyzed and compared, i.e., the analysis of the third harmonic of the stator currents and the first one of the zero- sequence voltage components. The Vold¿Kalman filtering order tracking algorithm is introduced and applied to track the harmonics of interest when the machine operates under a wide speed range and different load levels. This study also presents two reliable fault indicators especially focused to detect stator winding interturn faults under nonstationary speed conditions. Experimental results endorse the methodology proposed, showing its potential to carry out a reliable fault diagnosis scheme

  • Determination of the corona inception voltage in an extra high voltage substation connector

     Hernandez Guiteras, Joan; Riba Ruiz, Jordi Roger; Casals Torrens, Pau
    IEEE Transactions on dielectrics and electrical insulation
    Vol. 20, num. 1, p. 82-88
    DOI: 10.1109/TDEI.2013.6451344
    Date of publication: 2013-02
    Journal article

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    Environmental life cycle assessment of rapeseed straight vegetable oil as self-supply agricultural biofuel  Open access

     Baquero Armans, Grau; Esteban Dalmau, Bernat; Puig Vidal, Rita; Riba Ruiz, Jordi Roger; Rius Carrasco, Antoni
    Renewable energy
    Vol. 50, p. 142-149
    DOI: 10.1016/j.renene.2012.06.0
    Date of publication: 2013-02-01
    Journal article

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    Biofuels are nowadays considered a questionable environmental alternative to fossil fuels. In that context, this work analyses the environmental impacts when introducing rapeseed on the traditional and current wheat and barley agricultural rotation by means of a comparative life cycle assessment (LCA). The introduction of rapeseed, the correctness of its conversion to obtain straight vegetable oil and its use as self-consumption biofuel in tractors are evaluated. Life cycle assessment is used in this work to evaluate the impacts of different considered scenarios. A sensitivity analysis has also been conducted. The results presented show a modest environmental improvement (diminishment of 6 out of the 10 analyzed environmental impacts) when introducing rapeseed to local crop rotations and its partial conversion to oil to be used as fuel in existing diesel engines. Additionally, the ratio between the energy obtained and the total energy input shows moderate positive results when comparing the latter case with the current one. Results from this study can be used to support research and decision making to assess the convenience of introducing alternative fuels in agricultural exploitations

  • A back-emf based method to detect magnet failures in PMSMs

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    IEEE transactions on magnetics
    Vol. 49, num. 1, p. 591-598
    DOI: 10.1109/TMAG.2012.2207731
    Date of publication: 2013
    Journal article

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    Demagnetization faults are troublesome because they have a profound impact on the overall performance of permanent magnet synchronous motors (PMSMs). This work presents and veri¿es experimentally a system to detect such faults which is based on the measure of the zero sequence voltage component (ZSVC). The proposed method is also appropriate for inverter fed machines and is particularly useful when dealing with fault tolerant systems. A fault severity index which allows quantifying the harshness of such faults is also proposed and its behavior is analyzed from experimental data. Features of the proposed method include low computational burden, simplicity and high sensitivity. Experimental results conducted at different speed and load conditions show the potential of the proposed fault severity index for online diagnosis of demagnetization failures

  • Feasibility analysis of reduced-scale air breakdown tests in high voltage laboratories combined with the use of scaled test cages

     Hernandez Guiteras, Joan; Riba Ruiz, Jordi Roger; Casals Torrens, Pau; Bosch Tous, Ricardo
    IEEE Transactions on dielectrics and electrical insulation
    Vol. 20, num. 5, p. 1590-1597
    DOI: 10.1109/TDEI.2013.6633688
    Date of publication: 2013-10
    Journal article

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    Breakdown and corona extra-and ultra-high voltage tests are expensive, timeconsuming and require large and extremely costly high-voltage halls, of which there are very few worldwide. Some of these limiting requirements may be minimized by using test cages and by applying reduced-scale tests. In this work the feasibility of performing breakdown reduced-scale tests combined with the use of test cages is analyzed. For this purpose a three-dimensional finite elements based methodology is introduced to determine the geometric dimensions of the test cage in order to adjust the test voltage according to the allowable output voltage of a conventional high-voltage laboratory. To validate the findings of this work, breakdown tests of a full-scale 500 kVRMS substation connector and a 1:3 reduced-scale model using test cages are conducted in a highvoltage laboratory, which maximum allowable output voltage is of 125 kVRMS. Results from this work show that by using appropriately designed test cages and scaled versions of the test samples the results may be scaled with high accuracy.

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    Magnet shape influence on the performance of AFPMM with demagnetization  Open access

     Saavedra Ordoñez, Harold; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    Annual Conference of the IEEE Industrial Electronics Society
    Presentation's date: 2013-11-13
    Presentation of work at congresses

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    In this paper the effect of the magnets shape on the AFPMM performance under a demagnetization fault has been analyzed by means of 3D-FEM simulations. Demagnetization faults in permanent magnet synchronous motors (PMSMs) may generate specific fault harmonic frequencies in the stator currents, output torque and the zero-sequence voltage component (ZSVC) spectra the ones can affect motor behavior, and so these parameters have been studied and compared, for each magnet configuration in each condition. These analyses are carried out to find out the more suitable geometry for an operation under healthy and faulty condition.

  • Redesign of a spherical corona shield for UHV substation connectors

     Hernandez Guiteras, Joan; Riba Ruiz, Jordi Roger; Saavedra Ordoñez, Harold
    International Conference on Power Engineering, Energy and Electrical Drives
    Presentation's date: 2013-05-15
    Presentation of work at congresses

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  • Inter-turn fault detection in five-phase PMSMs. Effects of the fault severity

     Saavedra Ordoñez, Harold; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives
    Presentation's date: 2013-08-30
    Presentation of work at congresses

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    This paper deals with the effects of inter-turn short circuit faults in five-phase permanent magnet synchronous motors (PMSMs). For this purpose a finiteelements model (FEM) of a faulty machine with 1, 2 and 4 inter-turns in short circuit is analyzed. From the results of this model the effects of these fault severities in the stator currents and zero-sequence voltage components (ZSVC) harmonics is analyzed and the possibility of developing a fault diagnosis scheme based on the changes in their spectral content is exposed. Moreover, the effect of the fault severity on the total power losses in the machine is presented. Inter-turn faults generate large circulating currents which may lead to catastrophic failures. Therefore it is very important to know the increase in power losses in the machine due to the occurrence of such faults for applying corrective actions at the precise time once the fault has been diagnosed.

  • Magnet shape influence on the performance of AFPMM in a torus configuration

     Saavedra Ordoñez, Harold; Riba Ruiz, Jordi Roger; Hernandez Guiteras, Joan; Romeral Martinez, Jose Luis
    International Conference on Power Engineering, Energy and Electrical Drives
    Presentation's date: 2013-05-16
    Presentation of work at congresses

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    The axial flux permanent magnet machine (AFPMM)is being increasingly demanded for special applications, particularly for transportation systems and concretely for inwheel applications. In this paper the effect of the magnets shape on the AFPMM performance has been analyzed by means of 3DFEM simulations. To this end the air-gap magnetic flux density, the back electromotive force (back-EMF), the cogging torque and the total torque waveforms of the analyzed AFPMMs with different magnets geometries have been studied and compared. The harmonic content of all these variables has been also analyzed. These analyses are carried out to find out the more suitable geometry for in-wheel applications and particularly to minimize the torque ripple of the AFPMM.

  • IEEE transactions on industrial electronics (1963)

     Riba Ruiz, Jordi Roger
    Vol. 61, num. 4
    Collaboration in journals

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  • IEEE transactions on industrial electronics

     Riba Ruiz, Jordi Roger
    Vol. 60, num. 9
    Collaboration in journals

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  • IEEE transactions on industrial electronics

     Riba Ruiz, Jordi Roger
    Vol. 60, num. 9
    Collaboration in journals

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  • Characterization of the surface tension of vegetable oils to be used as fuel in diesel engines

     Esteban Dalmau, Bernat; Riba Ruiz, Jordi Roger; Baquero Armans, Grau; Puig Vidal, Rita; Rius, Antonio
    Fuel (Guildford)
    Vol. 102, p. 231-238
    DOI: 10.1016/j.fuel.2012.07.042
    Date of publication: 2012-12
    Journal article

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    Straight vegetable oils may be used as fuel in existing diesel engines. However, some precautions should be taken into account because some of their physicochemical properties must be adjusted through tem- perature control to ensure enhanced combustion, thus avoiding premature aging of the engine. Although it is well known that surface tension plays a prevalent role in the fuel atomization process which affects the combustion quality, there is lack of published information about its variation with temperature when dealing with straight vegetable oils to be used as fuel in unmodified diesel engines. In this work, the surface tension of several vegetable oils is studied in a wide temperature interval. The optimal range of temperatures at which each vegetable oil should operate to adjust its properties to those of automotive diesel and biodiesel is found. Moreover, an empirical relationship between the dependence between surface tension and density is presented

  • Application of the zero-sequence voltage component to detect stator winding inter-turn faults in PMSMs

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    Electric power systems research
    Vol. 89, p. 38-44
    DOI: 10.1016/j.epsr.2012.02.012
    Date of publication: 2012-08
    Journal article

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    This paper develops and analyzes a methodology for detecting stator winding inter-turn faults in surface-mounted permanent magnet synchronous motors. The proposed methodology is based on monitoring the zero-sequence voltage component having into account the effects of the inverter that usually feeds the machine. The theoretical basis of such a method is established from the parametric model of the machine. Attributes of the method presented here include simplicity, high accuracy, low computational burden and high sensibility. Additionally, it is especially useful when dealing with fault tolerant systems. From this model the expression of the zero sequence voltage component is deduced, which is used to detect stator winding inter-turn faults. Both simulation and experimental results presented in this work show the potential of the proposed method to provide helpful and reliable data to carry out an online diagnosis of such faults.

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    Identificación de muestras de papel mediante espectrometria IR y métodos multivariables  Open access

     Riba Ruiz, Jordi Roger
    Afinidad: revista de química teórica y aplicada
    Vol. LXIX, num. 558, p. 87-94
    Date of publication: 2012-04-01
    Journal article

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    Actualmente en todo el mundo se consume una gran cantidad de papel reciclado. Ello ha provocado la fabricación de papel que contiene muchos tipos de impurezas, por lo que las empresas papeleras se están viendo con la necesidad de desarrollar métodos para controlar la calidad del papel entrante para así garantizar su calidad. Para ello en este trabajo se investiga un método muy rápido y no destructivo para identificar diferentes tipos de papel que permita desechar el papel entrante que no cumpla con unos requisitos mínimos de calidad. De este modo se puede mejorar el comportamiento de la máquina de papel y al mismo tiempo asegurar la calidad del producto final. Ello se hace en base al estudio de los espectros FTIR (espectroscopia del infrarrojo medio por transformada de Fourier) y NIR (espectroscopia del infrarrojo cercano) tratados mediante ICA (análisis de componentes independientes) como técnica multivariable de extracción de características para reducir la cantidad de variables utilizadas y k-NN (k vecinos más cercanos) como técnica de clasificación. Los resultados experimentales muestran que es posible identificar con éxito más de un 90% de las muestras estudiadas, de una forma rápida, muy automatizada y de forma no destructiva.

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    Temperature dependence of density and viscosity of vegetable oils  Open access

     Esteban Dalmau, Bernat; Riba Ruiz, Jordi Roger; Baquero Armans, Grau; Rius Carrasco, Antoni; Puig Vidal, Rita
    Biomass and bioenergy
    Vol. 42, p. 164-171
    DOI: 10.1016/j.biombioe.2012.03.007
    Date of publication: 2012-07
    Journal article

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    The straight use of vegetable oils as fuel in diesel engines entails adjusting several physical properties such as density and viscosity. By adequately heating the vegetable oil before entering the injection system, its physical parameters can reach values very close to that of diesel fuel. Consequently, by properly adjusting the temperature of vegetable oils used as fuel, it is possible to improve their combustion performance, thus avoiding premature engine aging due to incomplete burning. In this study the density and viscosity of several vegetable oils are studied within a wide variety of temperatures. The optimal range of temperatures at which each vegetable oil should operate in order to adjust its properties to those of automotive diesel and biodiesel is then found. Additionally an empirical relationship between the dependence of viscosity with density is presented. Thus, by means of the above-described relationship, through measuring the density of a given oil, its viscosity can be directly deduced

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    Comparative Study of Multivariate Methods to Identify Paper Finishes Using Infrared Spectroscopy  Open access

     Riba Ruiz, Jordi Roger; Canals Parelló, Trini; Cantero Gómez, Maria Rosa
    IEEE transactions on instrumentation and measurement
    Vol. 61, num. 4, p. 1029-1036
    DOI: 10.1109/TIM.2011.2173048
    Date of publication: 2012-03-09
    Journal article

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    Recycled paper is extensively used worldwide. In the last decades its market has expanded considerably. The increasing use of recycled paper in papermaking has led to the production of paper containing several types of impurities. Consequently, wastepaper mills are forced to implement quality control schemes for evaluating the incoming wastepaper stock, thus guarantying the specifications of the final product. The main objective of this work is to present a fast and reliable system for identifying different paper types. Therefore, undesirable paper types can be refused, improving the performance of the paper machine and the final quality of the paper manufactured. For this purpose two fast techniques, i.e., Fourier transform mid-infrared (FTIR) and reflectance near-infrared (*IR) were applied to acquire the infrared spectra of the paper samples. *ext, four processing multivariate methods, i.e., principal component analysis (PCA), canonical variate analysis (CVA), extended canonical variate analysis (ECVA) and support vector machines (SVM) were employed in the feature extraction –or dimension reduction– stage. Afterwards, the k nearest neighbors algorithm (k**) was used in the classification phase. Experimental results show the usefulness of the proposed methodology and the potential of both FTIR and *IR spectroscopic methods. Using the FTIR spectrum in association with SVM and k** the system achieved maximum classification accuracy of 100%, whereas using the *IR spectrum in association with ECVA or SVM and k** the system achieved maximum classification accuracy of 96.4%

  • Detection of demagnetization faults in surface-mounted permanent magnet synchronous motors by means of the zero-sequence voltage component

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Delgado Prieto, Miquel; Romeral Martinez, Jose Luis
    IEEE transactions on energy conversion
    Vol. 27, num. 1, p. 42-51
    DOI: 10.1109/TEC.2011.2176127
    Date of publication: 2012-03-01
    Journal article

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    This paper develops and analyzes an online methodology to detect demagnetization faults in surface-mounted permanent magnet synchronous motors. The proposed methodology, which takes into account the effect of the inverter that feeds the machine, is based on monitoring the zero-sequence voltage component of the stator phase voltages. The theoretical basis of the proposed method has been established. Attributes of the method presented here include simplicity, very low computational burden, and high sensibility. Since the proposed method requires access to the neutral point of the stator windings, it is especially useful when dealing with fault tolerant systems. A simple expression of the zero-sequence voltage component is deduced, which is proposed as a fault indicator parameter. Both simulation and experimental results presented in this paper show the potential of the proposed method to provide helpful and reliable data to carry out an online diagnosis of demagnetization failures in the rotor permanent magnets.

  • Electrical and Magnetic Faults Diagnosis in Permanent Magnet Synchronous Motors  Open access  awarded activity

     Urresty Betancourt, Julio César
    Department of Electronic Engineering, Universitat Politècnica de Catalunya
    Theses

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    Permanent magnet synchronous motors (PMSMs) are an alternative in critical applications where high-speed operation, compactness and high efficiency are required. In these applications it is highly desired to dispose of an on-line, reliable and cost-effective fault diagnosis method. Fault prediction and diagnosis allows increasing electric machines performance and raising their lifespan, thus reducing maintenance costs, while ensuring optimum reliability, safe operation and timely maintenance. Consequently this thesis is dedicated to the diagnosis of magnetic and electrical faults in PMSMs. As a first step, the behavior of a healthy machine is studied, and with this aim a new 2D finite element method (FEM) modelbased system for analyzing surface-mounted PSMSs with skewed rotor magnets is proposed. It is based on generating a geometric equivalent non-skewed permanent magnet distribution which accounts for the skewed distribution of the practical rotor, thus avoiding 3D geometries and greatly reducing the computational burden of the problem. To diagnose demagnetization faults, this thesis proposes an on-line methodology based on monitoring the zero-sequence voltage component (ZSVC). Attributes of the proposed method include simplicity, very low computational burden and high sensibility when compared with the well known stator currents analysis method. A simple expression of the ZSVC is deduced, which can be used as a fault indicator parameter. Furthermore, mechanical effects arising from demagnetization faults are studied. These effects are analyzed by means of FEM simulations and experimental tests based on direct measurements of the shaft trajectory through self-mixing interferometry. For that purpose two perpendicular laser diodes are used to measure displacements in both X and Y axes. Laser measurements proved that demagnetization faults may induce a quantifiable deviation of the rotor trajectory. In the case of electrical faults, this thesis studies the effects of resistive unbalance and stator winding inter-turn short-circuits in PMSMs and compares two methods for detecting and discriminating both faults. These methods are based on monitoring and analyzing the third harmonic component of the stator currents and the first harmonic of the ZSVC. Finally, the Vold-Kalman filtering order tracking algorithm is introduced and applied to extract selected harmonics related to magnetic and electrical faults when the machine operates under variable speed and different load levels. Furthermore, different fault indicators are proposed and their behavior is validated by means of experimental data. Both simulation and experimental results show the potential of the proposed methods to provide helpful and reliable data to carry out a simultaneous diagnosis of resistive unbalance and stator winding inter-turn faults.

  • Analysis of demagnetization faults in surface-mounted permanent magnet synchronous with inter-turns and phase-to-ground short-circuits

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis; Saavedra Ordoñez, Harold
    International Conference on Electrical Machines
    p. 2384-2389
    DOI: 10.1109/ICElMach.2012.6350217
    Presentation's date: 2012-09-03
    Presentation of work at congresses

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    Demagnetization faults are troublesome in permanent magnet synchronous motors since they may greatly reduce their performance and efficiency. Additionally, the temperature of the magnets deeply influences the remanent flux density. Hence, the temperature may have a demagnetization effect on the magnets. This work studies the behavior of a surface-mounted permanent magnet synchronous motor running under inter-turn and phase-to-ground short-circuits faults. Concretely, the temperature increase of such faults and a potential reversible or irreversible demagnetization of the rotor magnets are analyzed. The analysis is based on 2D FEM simulations which includes rotor magnet skew. The simulations conducted in this work clearly show that inter-turn faults do not lead to irreversible demagnetization. However, in case of a phase-to-ground short-circuit an irreversible demagnetization may take place instantaneously

  • Comparative life cycle analysis between traditional and organic farming local rotations to produce straight vegetable oil used as self-supply biofuel in agriculture

     Baquero Armans, Grau; Esteban Dalmau, Bernat; Rius Carrasco, Antoni; Puig Vidal, Rita; Riba Ruiz, Jordi Roger
    European Biomass Conference and Exhibition
    p. 2226-2228
    DOI: 10.5071/20thEUBCE2012-5AV.1.19
    Presentation's date: 2012-06-18
    Presentation of work at congresses

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  • Salinity effect on the corona onset for a 765 kV AC substation connector

     Hernandez Guiteras, Joan; Riba Ruiz, Jordi Roger; Sanllehi, Josep; Bosch Tous, Ricardo
    International Council on Large Electric Systems
    Presentation's date: 2012-08-29
    Presentation of work at congresses

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    Outdoor substations placed in coastal areas are affected by saline environments. In the technical literature it is found extensive information regarding insulations problems in presence of saline environments [1]. The accumulation of salts and other contaminants promotes the onset of partial discharges on the devices subjected to very high voltages. Insulators are also affected by this phenomenon. While rainfall has a cleaning effect on the insulator surface, humidity enhances the corrosion effect and degrades the performance of insulation [2], favouring onset conditions for partial discharge. Corrosion due to saline environments or dirt increases the roughness of the insulator surface, thus facilitating the appearance of partial discharges [3]. It is well known that the air pollution has a great impact on metals corrosion. Chloride ions are common in coastal environments, because seawater acts as a source of air mineralization. Deposition of chloride ions on metal surfaces intensifies metallic corrosion, thus degrading the conductor surface [4]. In this work the behaviour of a 765 kVRMS AC (line-to-line voltage) outdoor substation connector is analyzed when operating under both dry conditions and under wet saline environments by means of three-dimensional finite elements simulations (3D-FEM). FEM simulations show that the electric field strength in the connector surroundings does not exceed the electric breakdown strength for air under clean and dry atmospheric conditions when energized at its rated voltage, 765 kVRMS AC (line-to-line). These results are corroborated by means of experimental measurements carried out in a high-voltage laboratory. Both, the laboratory tests and the 3D-FEM simulations performed in this study concluded that the corona onset voltage is approximately 980 kVRMS AC (line-to-line voltage). Additionally, 3D-FEM simulations allow detecting the connector weakest points regarding to electrical stress. Hence, this software allows redesigning the connector geometry to optimize its performance, thus minimizing the corona occurrence risk and their associated unwanted effects. Additionally, FEM simulations performed under a saline atmosphere were carried out by including a thin conductive saline moisture layer acting as a wetting film on the connector surface. Results revealed that saline environments worsen the connector behaviour, thus favouring corona onset conditions and their related effects.Outdoor substations placed in coastal areas are affected by saline environments. In the technical literature it is found extensive information regarding insulations problems in presence of saline environments [1]. The accumulation of salts and other contaminants promotes the onset of partial discharges on the devices subjected to very high voltages. Insulators are also affected by this phenomenon. While rainfall has a cleaning effect on the insulator surface, humidity enhances the corrosion effect and degrades the performance of insulation [2], favouring onset conditions for partial discharge. Corrosion due to saline environments or dirt increases the roughness of the insulator surface, thus facilitating the appearance of partial discharges [3]. It is well known that the air pollution has a great impact on metals corrosion. Chloride ions are common in coastal environments, because seawater acts as a source of air mineralization. Deposition of chloride ions on metal surfaces intensifies metallic corrosion, thus degrading the conductor surface [4]. In this work the behaviour of a 765 kVRMS AC (line-to-line voltage) outdoor substation connector is analyzed when operating under both dry conditions and under wet saline environments by means of three-dimensional finite elements simulations (3D-FEM). FEM simulations show that the electric field strength in the connector surroundings does not exceed the electric breakdown strength for air under clean and dry atmospheric conditions when energized at its rated voltage, 765 kVRMS AC (line-to-line). These results are corroborated by means of experimental measurements carried out in a high-voltage laboratory. Both, the laboratory tests and the 3D-FEM simulations performed in this study concluded that the corona onset voltage is approximately 980 kVRMS AC (line-to-line voltage). Additionally, 3D-FEM simulations allow detecting the connector weakest points regarding to electrical stress. Hence, this software allows redesigning the connector geometry to optimize its performance, thus minimizing the corona occurrence risk and their associated unwanted effects. Additionally, FEM simulations performed under a saline atmosphere were carried out by including a thin conductive saline moisture layer acting as a wetting film on the connector surface. Results revealed that saline environments worsen the connector behaviour, thus favouring corona onset conditions and their related effects.

  • Economic assessment of forest chips versus heating oil in domestic boilers in the mediterranean region

     Esteban Dalmau, Bernat; Baquero Armans, Grau; Riba Ruiz, Jordi Roger; Puig Vidal, Rita; Rius Carrasco, Antoni
    European Biomass Conference and Exhibition
    p. 2344-2346
    DOI: 10.5071/20thEUBCE2012-5AV.2.17
    Presentation's date: 2012-06-18
    Presentation of work at congresses

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  • Study of rapeseed oil degradation in different storage conditions

     Esteban Dalmau, Bernat; Baquero Armans, Grau; Rius Carrasco, Antoni; Puig Vidal, Rita; Riba Ruiz, Jordi Roger
    European Biomass Conference and Exhibition
    p. 1792-1794
    DOI: DOI: 10.5071/20thEUBCE2012-3DV.4.43
    Presentation's date: 2012-06-21
    Presentation of work at congresses

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  • Access to the full text
    Use of Rapeseed Straight Vegetable Oil as Fuel Produced in Small-Scale Exploitations  Open access

     Baquero Armans, Grau; Esteban Dalmau, Bernat; Riba Ruiz, Jordi Roger; Puig Vidal, Rita; Rius Carrasco, Antoni
    Date of publication: 2011-08-01
    Book chapter

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    This chapter presents a method to produce rapeseed and process it to obtain rapeseed oil and rapeseed cake meal from a small-scale point of view. It also shows how rapeseed oil can be used as fuel in diesel engines for agriculture self-consumption. A production, processing and use-as-fuel model for rapeseed oil is also presented, analysing environmentally and economically the use of rapeseed oil as fuel compared to other agricultural production alternatives. The results are evaluated for dry Mediterranean area conditions

  • INTELLIGENT MONITORING SYSTEM BASED ON ACCOUSTIC EMISSIONS SENSING FOR PLANT CONDITION MONITORING AND PREVENTATIVE MAINTENANCE

     Ortega Redondo, Juan Antonio; Moreno Eguilaz, Juan Manuel; Garcia Espinosa, Antonio; Cusido Roura, Jordi; Riba Ruiz, Jordi Roger; Sala Caselles, Vicente Miguel; Delgado Prieto, Miguel; Romeral Martinez, Jose Luis
    Competitive project

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  • UHV connectors: optimization

     Hernandez Guiteras, Joan; Riba Ruiz, Jordi Roger
    Date: 2011-05-31
    Report

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    This document includes the optimization of substation connector geometries and protections for ± 800 kV DC and 1200 kV AC transmission systems. Connectors were obtained from SBI Connectors catalog using current geometries and materials. Parametric simulations have been carried out to determine the electric field on connectors surface as an indicator for corona performance. The document aims to provide the designer information about the relationship between design aspects and the corona effect.

  • Diseño térmico de un motor SRM de 30 kw.

     Riba Ruiz, Jordi Roger
    Date: 2011-02-25
    Report

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  • UHV connectors: state of the art

     Hernandez Guiteras, Joan; Riba Ruiz, Jordi Roger
    Date: 2011-11-09
    Report

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  • Investigación sobre accionamientos con máquinas de flujo axial de imanes permanentes para instalación en rueda de vehículos eléctricos

     Riba Ruiz, Jordi Roger; Delgado Prieto, Miguel; Urresty Betancourt, Julio; Sala Caselles, Vicente Miguel; Ortega Redondo, Juan Antonio; Garcia Espinosa, Antonio; Moreno Eguilaz, Juan Manuel; Cusido Roura, Jordi; Romeral Martinez, Jose Luis
    Competitive project

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  • Diseño electromagnético de un motor SRM de 30 kw

     Riba Ruiz, Jordi Roger
    Date: 2011-01-13
    Report

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  • Dynamic model for AC and DC contactors ¿ Simulation and experimental validation

     Riba Ruiz, Jordi Roger; Garcia Espinosa, Antonio; Cusido Roura, Jordi; Delgado Prieto, Miquel
    Simulation modelling practice and theory
    Vol. 19, num. 9, p. 1918-1932
    DOI: 10.1016/j.simpat.2011.05.005
    Date of publication: 2011-10-01
    Journal article

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  • Is it environmentally advantageous to use vegetable oil directly as biofuel instead of converting it to biodiesel?

     Esteban Dalmau, Bernat; Baquero Armans, Grau; Puig Vidal, Rita; Riba Ruiz, Jordi Roger; Rius Carrasco, Antoni
    Biomass and bioenergy
    Vol. 35, num. 3, p. 1317-1328
    DOI: 10.1016/j.biombioe.2010.12.025
    Date of publication: 2011-03
    Journal article

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    The oil price instability and the measures taken to reduce the increase in greenhouse gas emissions are the main factors promoting the development and use of environmentally friendly energies. From an energy efficiency point of view, biofuels constitute a renewable energy source and its use helps to reduce energy dependency on fossil fuels. The most used biofuels for transport worldwide are biodiesel (BD) and bioethanol. However, there are other options such as straight vegetable oil (SVO). SVO can be small-scale produced in local cooperatives through pressing, filtering and conditioning processes which are much simpler than the ones required for BD production. In this study a comparative life cycle assessment (LCA) of two biofuels obtained from Spanish rapeseed, namely small-scale SVO and large-scale BD, is performed. The LCA methodology allows the two biofuels¿ production and their rate of consumption in a vehicle (a truck) to be compared. In this manner, it is possible to assess which is environmentally advantageous: to use SVO directly as biofuel or to convert it to BD. Moreover, LCA is used in the study to calculate the energy return on investment index (EROI) and an energy conversion ratio to evaluate which biofuel is more energy efficient. The obtained results show the environmental benefits of using SVO instead of BD by analyzing representative impact categories defined by the CML and EDIP methods. A sensitivity analysis has also been conducted. EROI indexes for SVO and BD production show a clear preference for SVO as compared to BD.