http://hdl.handle.net/2117/3540 Fri, 24 May 2013 21:54:30 GMT 2013-05-24T21:54:30Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/19372 Title: Implementation of the Direct Torque Control (DTC) in current model, with current starting limiter Authors: Mino Aguilar, Gerardo; Muñoz Hernández, German Ardul; Romeral Martínez, José Luis; Cortez, Liliana; Saynes Torres, J. Abstract: This paper presents the scheme of Direct Torque Control (DTC) for induction motor drives, where flux and torque of the motor are estimated by the IM current model. Its scheme requires the knowledge of speed, rotor time constant and inductive parameters of the motor. The results prove the excellent characteristics for torque response and efficiency, which confirm the validity of this control scheme. Due to the rapid response offered by the DTC, this causes a high star current inversor protections activating. To resolve this, is presents the implementation of a closed loop of current vector the optimum switching table that limits the current and put into operation to the DTC. Experimental tests demonstrate effectiveness. Wed, 22 May 2013 11:30:26 GMT http://hdl.handle.net/2117/19372 2013-05-22T11:30:26Z Mino Aguilar, Gerardo; Muñoz Hernández, German Ardul; Romeral Martínez, José Luis; Cortez, Liliana; Saynes Torres, J. no current limiter, current model, DTC This paper presents the scheme of Direct Torque Control (DTC) for induction motor drives, where flux and torque of the motor are estimated by the IM current model. Its scheme requires the knowledge of speed, rotor time constant and inductive parameters of the motor. The results prove the excellent characteristics for torque response and efficiency, which confirm the validity of this control scheme. Due to the rapid response offered by the DTC, this causes a high star current inversor protections activating. To resolve this, is presents the implementation of a closed loop of current vector the optimum switching table that limits the current and put into operation to the DTC. Experimental tests demonstrate effectiveness. http://hdl.handle.net/2117/19288 Title: Accurate Bearing Faults Classification based on Statistical-Time Features, Curvilinear Component Analysis and Neural Networks Authors: Delgado Prieto, Miquel; Cirrincione,, Giansalvo; García Espinosa, Antonio; Ortega Redondo, Juan Antonio; Henao, Humberto Abstract: Bearing faults are the commonest form of malfunction associated with electrical machines. So far, the research has been carried out mainly in the detection of localized faults, but the diagnosis of distributed faults is still under development. In this context, this work presents a new scheme for detecting and classifying both kinds of faults. This work deals with a new diagnosis monitoring scheme, which is based on statistical-time features calculated from vibration signal, curvilinear component analysis for compression and visualization of the features behavior and a hierarchical neural network structure for classification. The obtained results from different operation conditions validate the effectiveness and feasibility of the proposed methodology. Thu, 16 May 2013 11:46:14 GMT http://hdl.handle.net/2117/19288 2013-05-16T11:46:14Z Delgado Prieto, Miquel; Cirrincione,, Giansalvo; García Espinosa, Antonio; Ortega Redondo, Juan Antonio; Henao, Humberto no Bearing faults are the commonest form of malfunction associated with electrical machines. So far, the research has been carried out mainly in the detection of localized faults, but the diagnosis of distributed faults is still under development. In this context, this work presents a new scheme for detecting and classifying both kinds of faults. This work deals with a new diagnosis monitoring scheme, which is based on statistical-time features calculated from vibration signal, curvilinear component analysis for compression and visualization of the features behavior and a hierarchical neural network structure for classification. The obtained results from different operation conditions validate the effectiveness and feasibility of the proposed methodology. http://hdl.handle.net/2117/19280 Title: A novel condition monitoring scheme for bearing faults based on Curvilinear Component Analysis and hierarchical neural networks Authors: Delgado Prieto, Miquel; Cirrincione,, Giansalvo; García Espinosa, Antonio; Ortega Redondo, Juan Antonio; Henao, Humberto Abstract: Mostly the faults in electrical machines are related with the bearings. Thus, a reliable bearing condition monitoring scheme able to detect either local or distributed defects are mandatory to avoid a breakdown in the machine. So far, the research has been carried out mainly in the detection of local faults, such as balls and raceways faults, but surface roughness is not so reported. This paper deals with a novel and reliable scheme capable to detect any fault that may occur in a bearing, based on EXIN Curvilinear Component Analysis, CCA, and Neural Network. The EXIN CCA, which is an improvement of the Curvilinear Component Analysis, has been conceived for data visualization, interpretation and classification for real time industrial applications. The effectiveness of this condition monitoring scheme has been verified by experimental results obtained from different operation conditions. Thu, 16 May 2013 09:59:44 GMT http://hdl.handle.net/2117/19280 2013-05-16T09:59:44Z Delgado Prieto, Miquel; Cirrincione,, Giansalvo; García Espinosa, Antonio; Ortega Redondo, Juan Antonio; Henao, Humberto no Mostly the faults in electrical machines are related with the bearings. Thus, a reliable bearing condition monitoring scheme able to detect either local or distributed defects are mandatory to avoid a breakdown in the machine. So far, the research has been carried out mainly in the detection of local faults, such as balls and raceways faults, but surface roughness is not so reported. This paper deals with a novel and reliable scheme capable to detect any fault that may occur in a bearing, based on EXIN Curvilinear Component Analysis, CCA, and Neural Network. The EXIN CCA, which is an improvement of the Curvilinear Component Analysis, has been conceived for data visualization, interpretation and classification for real time industrial applications. The effectiveness of this condition monitoring scheme has been verified by experimental results obtained from different operation conditions. http://hdl.handle.net/2117/19262 Title: STLF in the user-side for an iEMS based on evolutionary training of adaptive networks Authors: Cárdenas Araújo, Juan José; Giacometto Torres, Francisco; García Espinosa, Antonio; Romeral Martínez, José Luis Abstract: It is a fact that the short-term load forecasting (STLF)in the user side is growing interest. Consequently, intelligent energy management systems (iEMSs) are including this capability in order to take autonomous decisions. In this context, this paper presents a new STLF scheme based on Adaptative Networks Fuzzy Inference Systems (ANFIS). This ANFIS has an exponential output membership functions (e-ANFIS) and has been trained by means of a novel evolutionary training algorithm (ETA). Due to the computational burden required by ETA, parallel computing was used to eliminate this problem especially for embedded applications. This new scheme has been tested with real data from an automotive factory and it shows better results in comparison with typical adaptative network structures (neural network and ANFIS). Wed, 15 May 2013 15:19:10 GMT http://hdl.handle.net/2117/19262 2013-05-15T15:19:10Z Cárdenas Araújo, Juan José; Giacometto Torres, Francisco; García Espinosa, Antonio; Romeral Martínez, José Luis no It is a fact that the short-term load forecasting (STLF)in the user side is growing interest. Consequently, intelligent energy management systems (iEMSs) are including this capability in order to take autonomous decisions. In this context, this paper presents a new STLF scheme based on Adaptative Networks Fuzzy Inference Systems (ANFIS). This ANFIS has an exponential output membership functions (e-ANFIS) and has been trained by means of a novel evolutionary training algorithm (ETA). Due to the computational burden required by ETA, parallel computing was used to eliminate this problem especially for embedded applications. This new scheme has been tested with real data from an automotive factory and it shows better results in comparison with typical adaptative network structures (neural network and ANFIS). http://hdl.handle.net/2117/19172 Title: New strategy to minimize dead-time distortion in DCI-NPC power amplifiers using COE-error injection Authors: Resano, Tomas; Sala Caselles, Vicenç; Romeral Martínez, José Luis; Moreno Eguilaz, Juan Manuel Abstract: The DCI-NPC topology has become one of the best options to optimize energy efficiency in the world of high power and high quality amplifiers. This can use an analog PWM modulator that is sensitive to generate distortion or error, mainly for two reasons: Carriers Amplitude Error (CAE) and Carriers Offset Error (COE). Other main error and distortion sources in the system is the Dead-Time (td). This is necessary to guarantee the proper operation of the power amplifier stage so that errors and distortions originated by it are unavoidable. This work proposes a negative COE generation to minimize the distortion effects of td. Simulation and experimental results validates this strategy. Mon, 13 May 2013 08:48:31 GMT http://hdl.handle.net/2117/19172 2013-05-13T08:48:31Z Resano, Tomas; Sala Caselles, Vicenç; Romeral Martínez, José Luis; Moreno Eguilaz, Juan Manuel no Amplifiers, Transducers, Equipment The DCI-NPC topology has become one of the best options to optimize energy efficiency in the world of high power and high quality amplifiers. This can use an analog PWM modulator that is sensitive to generate distortion or error, mainly for two reasons: Carriers Amplitude Error (CAE) and Carriers Offset Error (COE). Other main error and distortion sources in the system is the Dead-Time (td). This is necessary to guarantee the proper operation of the power amplifier stage so that errors and distortions originated by it are unavoidable. This work proposes a negative COE generation to minimize the distortion effects of td. Simulation and experimental results validates this strategy. http://hdl.handle.net/2117/19170 Title: Evaluation of trr distorting effects reduction in DCI-NPC multilevel power amplifiers by using SiC diodes and MOSFET technologies Authors: Sala Caselles, Vicenç; Resano, Tomas; Romeral Martínez, José Luis; Moreno Eguilaz, Juan Manuel Abstract: In the last decade, the Power Amplifier applications have used multilevel diode-clamped-inverter or neutral-point-clamped (DCI-NPC) topologies to present very low distortion at high power. In these applications a lot of research has been done in order to reduce the sources of distortion in the DCI-NPC topologies. One of the most important sources of distortion, and less studied, is the reverse recovery time (trr) of the clamp diodes and MOSFET parasitic diodes. Today, with the emergence of Silicon Carbide (SiC) technologies, these sources of distortion are minimized. This paper presents a comparative study and evaluation of the distortion generated by different combinations of diodes and MOSFETs with Si and SiC technologies in a DCI-NPC multilevel Power Amplifier in order to reduce the distortions generated by the non-idealities of the semiconductor devices. Mon, 13 May 2013 08:41:23 GMT http://hdl.handle.net/2117/19170 2013-05-13T08:41:23Z Sala Caselles, Vicenç; Resano, Tomas; Romeral Martínez, José Luis; Moreno Eguilaz, Juan Manuel no Amplifiers, Transducers, Equipment In the last decade, the Power Amplifier applications have used multilevel diode-clamped-inverter or neutral-point-clamped (DCI-NPC) topologies to present very low distortion at high power. In these applications a lot of research has been done in order to reduce the sources of distortion in the DCI-NPC topologies. One of the most important sources of distortion, and less studied, is the reverse recovery time (trr) of the clamp diodes and MOSFET parasitic diodes. Today, with the emergence of Silicon Carbide (SiC) technologies, these sources of distortion are minimized. This paper presents a comparative study and evaluation of the distortion generated by different combinations of diodes and MOSFETs with Si and SiC technologies in a DCI-NPC multilevel Power Amplifier in order to reduce the distortions generated by the non-idealities of the semiconductor devices. http://hdl.handle.net/2117/19144 Title: Clamping diode caused distortion in multilevel NPC Full-Bridge audio power amplifiers Authors: Sala Caselles, Vicenç; Salehi Arashloo Arashloo, Ramin; Moreno Eguilaz, Juan Manuel; Salehifar, Mehdi; Romeral Martínez, José Luis Abstract: This paper presents a study and analysis of the distorting effects of clamped diodes in multilevel DCI-NPC topology applied to high power and high quality audio-amplifier. The main distorting sources of error are characterized, which are due to the clamped-diodes non-idealities; and they are evaluated for typical commercial diodes values and working conditions. Through this study the distorting contribution of each non-ideality can be quantified, and the influence of the system operating parameters, such as reactive current angle and modulation index, are highlighted. Finally, it is presented the table of optimal parameters that a commercial diode should have to ensure proper operation of the amplifier under rated power and quality specification. Thu, 09 May 2013 10:36:55 GMT http://hdl.handle.net/2117/19144 2013-05-09T10:36:55Z Sala Caselles, Vicenç; Salehi Arashloo Arashloo, Ramin; Moreno Eguilaz, Juan Manuel; Salehifar, Mehdi; Romeral Martínez, José Luis no Audio-frequency amplifiers; Diodes; Distortion; Modulation; Power amplifiers This paper presents a study and analysis of the distorting effects of clamped diodes in multilevel DCI-NPC topology applied to high power and high quality audio-amplifier. The main distorting sources of error are characterized, which are due to the clamped-diodes non-idealities; and they are evaluated for typical commercial diodes values and working conditions. Through this study the distorting contribution of each non-ideality can be quantified, and the influence of the system operating parameters, such as reactive current angle and modulation index, are highlighted. Finally, it is presented the table of optimal parameters that a commercial diode should have to ensure proper operation of the amplifier under rated power and quality specification. http://hdl.handle.net/2117/19039 Title: A novel AC-AC converter based SiC for domestic induction cooking applications Authors: Salehifar, Mehdi; Moreno Eguilaz, Juan Manuel; Sala Caselles, Vicenç; Romeral Martínez, José Luis Abstract: This paper presents the analysis and design of a new high frequency ac-ac converter applied to domestic induction heating. The proposed topology uses only four switches to control power. Converter operation is same as a conventional class D inverter. Working above the resonant frequency, a sinusoidal input current and a unit power factor are obtained. To bring higher efficiency and power density, application of emerging SiC technology in proposed converter has been evaluated. The analytical and simulation results have been verified by means of a 380-W induction heating prototype. Mon, 29 Apr 2013 13:47:29 GMT http://hdl.handle.net/2117/19039 2013-04-29T13:47:29Z Salehifar, Mehdi; Moreno Eguilaz, Juan Manuel; Sala Caselles, Vicenç; Romeral Martínez, José Luis no This paper presents the analysis and design of a new high frequency ac-ac converter applied to domestic induction heating. The proposed topology uses only four switches to control power. Converter operation is same as a conventional class D inverter. Working above the resonant frequency, a sinusoidal input current and a unit power factor are obtained. To bring higher efficiency and power density, application of emerging SiC technology in proposed converter has been evaluated. The analytical and simulation results have been verified by means of a 380-W induction heating prototype. http://hdl.handle.net/2117/19037 Title: Fault tolerant operation of a five phase converter for PMSM drives Authors: Salehifar, Mehdi; Salehi Arashloo Arashloo, Ramin; Moreno Eguilaz, Juan Manuel; Sala Caselles, Vicenç; Romeral Martínez, José Luis Abstract: In this paper a five phase fault tolerant converter is proposed for permanent magnet (PM) drives. The proposed configuration is an extension of conventional three phase double switch redundant topologies. In contrast to three phase systems,the proposed configuration has more flexibility and reliability regarding simultaneous faults in more than one phase. Different faulty cases are explained. Optimal reconfiguration strategies are derived under several faulty conditions. Design criteria are defined and a comparative loss analysis is conducted on converter behavior under various conditions. Simulation results are included to validate the theory. Mon, 29 Apr 2013 13:26:32 GMT http://hdl.handle.net/2117/19037 2013-04-29T13:26:32Z Salehifar, Mehdi; Salehi Arashloo Arashloo, Ramin; Moreno Eguilaz, Juan Manuel; Sala Caselles, Vicenç; Romeral Martínez, José Luis no In this paper a five phase fault tolerant converter is proposed for permanent magnet (PM) drives. The proposed configuration is an extension of conventional three phase double switch redundant topologies. In contrast to three phase systems,the proposed configuration has more flexibility and reliability regarding simultaneous faults in more than one phase. Different faulty cases are explained. Optimal reconfiguration strategies are derived under several faulty conditions. Design criteria are defined and a comparative loss analysis is conducted on converter behavior under various conditions. Simulation results are included to validate the theory. http://hdl.handle.net/2117/18736 Title: Simulación del proceso de emisión acústica. Generación de ondas elásticas transitorias en un engranaje bajo tensión Authors: Cobo Molina, Raúl; Rezano Inza, Tomás; Riera Colom, María Dolores; Romeral Martínez, José Luis Abstract: Con el objetivo de que el funcionamiento de una máquina sea el correcto es imperativo asegurar que existe un buen mantenimiento predictivo. Es conveniente tener un sistema inteligente y dispositivos capaces de detectar fallos en fases tempranas. Los fallos más comunes en máquinas industriales son todos aquellos relacionados con los sistemas de transmisión de potencia. La técnica de emisión acústica (EA) es el último enfoque para detectar e identificar defectos en rodamientos, cajas de cambio y uniones mecánicas. La emisión acústica (EA) es el fenómeno de generación de ondas elásticas transitorias en materiales bajo tensión. Cuando el material está sometido a un cierto nivel de tensión, una liberación rápida de energía de deformación tiene lugar en forma de ondas elásticas, las cuales pueden ser detectadas mediante transductores colocados en la pieza en cuestión. El objetivo de este trabajo es proporcionar una caracterización de las ondas elásticas que emanan de grietas localizadas entre el flanco y el valle de un engranaje. Las señales han sido registradas usando transductores colocados en la superficie del engranaje (a media distancia entre el eje y los dientes). El método de los elementos finitos ha sido utilizado para simular las ondas elásticas emitidas durante el crecimiento de las grietas. El modelo de simulación está basado en suposiciones elásticas y se ha llevado a cabo mediante Abaqus. Estos resultados han sido comparados con los resultados experimentales.; In order to have a machine that functions well it is imperative to ensure that there is a good predictive maintenance. An intelligent system and devices able to detect the fault in its early stage is then convenient. The most common failures in industrial machines are those related to the power transmission systems. Acoustic Emission (AE) is the latest approach in detecting and identifying faults in bearings, gearboxes and mechanical couplings. Acoustic Emission (AE) is the phenomenon of transient elastic wave generation in materials under stress. When the material is subjected to stress at a certain level, a rapid release of strain energy takes place in the form of an elastic wave which can be detected by transducers placed on it. The objective of this work is to provide a characterization of elastic waves emanating from cracks located between the flank and the valley of a gear. The signals have been recorded using transducers attached to the surface of the gear (midway between the shaft and the teeth). FE modeling has been used to simulate the elastic waves emitted from fatigue crack growth. The model is based on linear elasticity assumptions and undertaken using Abaqus. These results have been compared with the experimental ones. Tue, 09 Apr 2013 13:56:38 GMT http://hdl.handle.net/2117/18736 2013-04-09T13:56:38Z Cobo Molina, Raúl; Rezano Inza, Tomás; Riera Colom, María Dolores; Romeral Martínez, José Luis no Con el objetivo de que el funcionamiento de una máquina sea el correcto es imperativo asegurar que existe un buen mantenimiento predictivo. Es conveniente tener un sistema inteligente y dispositivos capaces de detectar fallos en fases tempranas. Los fallos más comunes en máquinas industriales son todos aquellos relacionados con los sistemas de transmisión de potencia. La técnica de emisión acústica (EA) es el último enfoque para detectar e identificar defectos en rodamientos, cajas de cambio y uniones mecánicas. La emisión acústica (EA) es el fenómeno de generación de ondas elásticas transitorias en materiales bajo tensión. Cuando el material está sometido a un cierto nivel de tensión, una liberación rápida de energía de deformación tiene lugar en forma de ondas elásticas, las cuales pueden ser detectadas mediante transductores colocados en la pieza en cuestión. El objetivo de este trabajo es proporcionar una caracterización de las ondas elásticas que emanan de grietas localizadas entre el flanco y el valle de un engranaje. Las señales han sido registradas usando transductores colocados en la superficie del engranaje (a media distancia entre el eje y los dientes). El método de los elementos finitos ha sido utilizado para simular las ondas elásticas emitidas durante el crecimiento de las grietas. El modelo de simulación está basado en suposiciones elásticas y se ha llevado a cabo mediante Abaqus. Estos resultados han sido comparados con los resultados experimentales. http://hdl.handle.net/2117/18609 Title: Load forecasting in the user side using wavelet-ANFIS Authors: Giacometto Torres, Francisco; Cárdenas Araújo, Juan José; Kampouropoulos, Konstantinos; Romeral Martínez, José Luis Abstract: At present, the intelligent energy management systems (IEMS) are used to maximiz the relation between productivity and cost using a variety of energy sources. Tn this work, we present a method of short-time load forecasting, using the ANFTS model and a component of preprocessing based in the discrete wavelet transform; the models was implemented in the user-side, analyzing real data of a factory in order to test the proposed algorithm Thu, 04 Apr 2013 11:34:29 GMT http://hdl.handle.net/2117/18609 2013-04-04T11:34:29Z Giacometto Torres, Francisco; Cárdenas Araújo, Juan José; Kampouropoulos, Konstantinos; Romeral Martínez, José Luis no discrete wavelet transforms, energy management systems, energy resources, fuzzy neural nets, inference mechanisms, load forecasting, power engineering computing, power system economics, power system simulation At present, the intelligent energy management systems (IEMS) are used to maximiz the relation between productivity and cost using a variety of energy sources. Tn this work, we present a method of short-time load forecasting, using the ANFTS model and a component of preprocessing based in the discrete wavelet transform; the models was implemented in the user-side, analyzing real data of a factory in order to test the proposed algorithm http://hdl.handle.net/2117/18569 Title: On the effect of accessible neutral point in fault tolerant five phase PMSM drives Authors: Salehi Arashloo Arashloo, Ramin; Salehifar, Mehdi; Romeral Martínez, José Luis Abstract: This study deals with the fault tolerant vector control strategies of a five-phase permanent-magnet (PM) machine. The analysis is focused on the effect of accessible neutral point under faulty conditions. Open circuit fault of one and two phases are considered, and proper control strategies are proposed to reduce the amplitude of currents in the remaining healthy phases. Simulations under both healthy and faulty conditions have been undertaken, and the effect of accessible neutral point on current amplitudes and torque ripple is evaluated. Wed, 03 Apr 2013 11:15:17 GMT http://hdl.handle.net/2117/18569 2013-04-03T11:15:17Z Salehi Arashloo Arashloo, Ramin; Salehifar, Mehdi; Romeral Martínez, José Luis no Control strategies, Fault tolerant control, Fault-tolerant, Faulty condition, Five phase, Multiphase machines, Neutral points, On currents, Open circuit faults, Permanent magnet motor, Permanent-magnet machine, PMSM drives, Torque ripples, Vector control strategies This study deals with the fault tolerant vector control strategies of a five-phase permanent-magnet (PM) machine. The analysis is focused on the effect of accessible neutral point under faulty conditions. Open circuit fault of one and two phases are considered, and proper control strategies are proposed to reduce the amplitude of currents in the remaining healthy phases. Simulations under both healthy and faulty conditions have been undertaken, and the effect of accessible neutral point on current amplitudes and torque ripple is evaluated. http://hdl.handle.net/2117/17228 Title: Environmental life cycle assessment of rapeseed straight vegetable oil as self-supply agricultural biofuel Authors: Baquero Armans, Grau; Esteban Dalmau, Bernat; Puig Vidal, Rita; Riba Ruiz, Jordi-Roger; Rius Carrasco, Antoni Abstract: 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 Wed, 09 Jan 2013 11:13:35 GMT http://hdl.handle.net/2117/17228 2013-01-09T11:13:35Z Baquero Armans, Grau; Esteban Dalmau, Bernat; Puig Vidal, Rita; Riba Ruiz, Jordi-Roger; Rius Carrasco, Antoni no 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 http://hdl.handle.net/2117/17216 Title: Identificación de muestras de papel mediante espectrometria IR y métodos multivariables Authors: Riba Ruiz, Jordi-Roger Abstract: 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. Tue, 08 Jan 2013 17:03:47 GMT http://hdl.handle.net/2117/17216 2013-01-08T17:03:47Z Riba Ruiz, Jordi-Roger no 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. http://hdl.handle.net/2117/17127 Title: Salinity effect on the corona onset for a 765 kV AC substation connector Authors: Hernández Guiteras, Joan; Riba Ruiz, Jordi-Roger; Sanllehi, Josep; Bosch Tous, Ricardo Abstract: 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. Thu, 13 Dec 2012 10:52:45 GMT http://hdl.handle.net/2117/17127 2012-12-13T10:52:45Z Hernández Guiteras, Joan; Riba Ruiz, Jordi-Roger; Sanllehi, Josep; Bosch Tous, Ricardo no 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.