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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Exploring the Association between Proximity to Industrial Wind Turbines and Self-Reported Health Outcomes in Ontario, Canada

Paller, Claire January 2014 (has links)
Background: Wind turbines are a form of renewable energy, which generate electricity from wind energy, a practice dating back over 100 years. More recently, large-scale wind energy developments have started to employ one or several industrial wind turbines, which produce the majority of wind energy in Ontario. The production of electricity from the movement of industrial wind turbine motor blades creates both mechanical and aerodynamic noise. This type of environmental noise is a growing public health concern, especially for residents living close to industrial wind turbines. A body of evidence now exists to suggest that industrial wind turbine noise can impair health and contribute to annoyance and sleep disturbance. However, in Ontario, little is known about how industrial wind turbines impact people living in their vicinity. Objectives: This investigation was a cross-sectional study involving eight Ontario communities that contain greater than ten industrial wind turbines. The objectives of this study were to explore the association between proximity to industrial wind turbines and self-reported health effects, specifically quality of life (both physical and mental health) and sleep disturbance, in residents living close to wind turbines. Dose-response relationships were also explored in an attempt to investigate acceptable exposure levels and appropriate setback distances for industrial wind turbines. Methods: Eight wind farms in Ontario were selected for analysis. For this cross-sectional study, the ???Quality of Life and Renewable Energy Technologies Study??? survey was used to measure the impact of industrial wind turbines on health. Using Canada Post???s Unaddressed Admail Service, surveys were sent to 4,876 residences near industrial wind turbines in these eight communities. Survey responses were sent back to the University of Waterloo and data from the surveys were used for analysis. Descriptive analyses were performed and multiple regression models were run to investigate the effect of the main independent variable of interest (distance to nearest industrial wind turbine) on the various outcome variables. Descriptive statistics, including means and standard deviations were performed on a number of dependent and independent variables including age, sex, time in home, number of industrial wind turbines within 2,000 meters and sleep and health outcomes. Results: In total, 412 surveys were returned (8.45% response rate); 16 of these survey respondents did not provide their home address. Therefore, 396 surveys were included in the analysis. The mean self-reported distances of survey respondents to wind farms was 2,782 meters +-3,950 meters (range: 0.40-55,000 meters). The mean calculated distance from residence to the closest industrial wind turbine was 4,523 meters +-4,420 meters (range: 316-22,661 meters). The difference between the calculated and perceived distance measurements was statistically significant (P<0.001) with survey respondents reporting that they live, on average, 1,741 meters closer to wind farms than they actually do. The relationship between Pittsburgh Sleep Quality Index and ln(distance) was found to be statistically significant (P=0.01) when controlling for age, gender and county, meaning that as distance increased (move further away from an industrial wind turbine), Pittsburgh Sleep Quality Index decreased (i.e. sleep improved) in a logarithmic relationship. Among the eight Wind Turbine Syndrome index variables, the relationship between vertigo and ln(distance) was statistically significant (P<0.001) when controlling for age, gender, and county. Additionally, the relationship between tinnitus and ln(distance) approached statistical significance (P=0.08) when controlling for age, gender and county. Both vertigo and tinnitus were worse among participants living closer to industrial wind turbines. Conclusion: Study findings suggest that industrial wind turbines could have an impact on health. Using a sample of rural Ontario residents (although not necessarily representative of the target population), this study explored the quality of life (both physical and mental health) and sleep disturbance of residents living in the vicinity of industrial wind turbines. However, because of study limitations, there are many questions still to be answered before firm conclusions can be drawn. Based on the findings of this study it is recommended that further studies be carried out to examine the effects of low-level stressors, such as industrial wind turbine noise, on health. Specifically, study findings suggest that future research should focus on the effects of industrial wind turbine noise on sleep disturbance and symptoms of inner ear problems. Although the study findings could suggest that there is a possible association between various health outcomes and how far someone lives from an industrial wind turbine, it is important to remember that there are limitations to these conclusions.
192

Design of a robust speed and position sensorless decoupled P-Q controlled doubly-fed induction generator for variable-speed wind energy applications

Gogas, Kyriakos. January 2007 (has links)
Wind energy is a relatively young but rapidly expanding industry. In order for wind generation to be cost effective, it must produce energy at a minimum cost per dollar of investment. Performance characteristics such as power output versus wind speed must be optimized in order to compete with other energy sources. Also, if the utility uses wind power for a part of its generation, the output power of these turbines must have the same high quality and reliability when it enters the utility grid. The ability to vary operating speed is important in wind generation because it allows for an optimization of the transfer of power from the wind to the turbine shaft. Doubly-fed induction generators (DFIG) are an interesting solution for variable-speed systems with limited variable speed range, and are typically used in wind energy conversion systems. / The objectives of this thesis are to implement a decoupled P-Q control of a DFIG that does not rely on mechanical sensors and to design a speed and position sensorless algorithm that is robust to variations of the values of the machine parameters. The sensorless DFIG control algorithm presented in this thesis is based on a modified phasedlock loop with an improved positioning algorithm. With the measured stator voltages, stator and rotor currents, the speed and position of the DFIG are estimated. The speed is estimated independent of machine parameters, which results in a significant improvement in speed control robustness to parameter variations. In addition, the algorithm avoids using differentiation, which significantly improves its immunity to noise and does not require the measurement of the rotor voltages. Also, it is shown that the positioning algorithm has an improved operation in generator mode. Although the accuracy of the positioning algorithm is depended on machine parameters; it is shown with the designed controller that the P-Q decoupled control is robust to changes of machine parameters. Theoretical and simulation results are validated on an experimental setup.
193

Association Between Industrial Wind Turbine Noise and Sleep Quality in a Comparison Sample of Rural Ontarians

Lane, James January 2013 (has links)
Background: Wind turbines (WTs) are an emerging source of renewable energy in Ontario. One concern is that aerodynamic and mechanical noise produced by the WTs results in sleep disturbance in residents living near such facilities. However, evidence to date is primarily self-reported, with no objective measures of the impact on sleep quality currently in the literature. Objective: The objective of this study was to determine if the presence of a grid connected WT is a risk factor for poor sleep quality and if wind turbine noise is associated with sleep parameters. The hypothesis was that individuals residing within fifteen hundred meters of a WT experience poorer sleep, compared to those who do not reside near a WT. Methods: A daily sleep diary and actigraphy-derived measures of sleep quality were obtained from twelve participants from a WT community in rural Ontario and ten participants from a comparison community with no wind power installations. Sound level meters were used to assess the equivalent (LAeq) and maximum (LAmax) sound pressure levels within the bedroom. A variety of statistical analysis were performed to determine co-variation between variables, noise thresholds for sleep disturbance, and risk for poor sleep quality. Results: A total of 110 person-nights and 12,971 sleep epochs were observed. Participants in the exposed group lived at a mean distance of 795 m from the closest WT (range 474 m–1085 m). Although numerous actigraphy-derived sleep parameters were poorer in the exposed group, including lower average sleep efficiency (89% vs. 92%), longer sleep onset latency (6 min vs. 4 min), and longer wake after sleep onset (42 min vs. 29 min), the differences were not statistically significant. When the data was dichotomized by quality of sleep, the prevalence of poor sleep in the exposed group was greater than in the unexposed group (22 vs. 11 per 100 person-nights), although the results of logistic regression modeling indicated that the differences were not statistically significant (after adjustment for age and sex). Findings from the analysis of sleep epochs showed an association between awakenings and LAmax (during the sleep epoch) only for noise events above 55 dBA. No significant differences in sleep parameters derived from the sleep diaries were found between the groups. Conclusion: Both actigraphy and sleep diaries can provide valuable information to understand the impact of industrial WTs on the quality of sleep for residents living in the vicinity. This pilot study had a small sample size which reduced the likelihood of identifying differences in sleep quality between the exposed and unexposed groups. Additionally, measurements were obtained during periods of relatively low wind speeds (nightly power outputs ranged from 1 to 34 MW or 0.5 to 17% capacity) thus, limiting the generalizability of the findings. Findings of poorer mean values of numerous sleep parameters in the exposed group support the need for more extensive research in the area. Low response to noise events up to 45 dBA was an interesting finding that also merits further investigation. Assessment of WT noise is complex and noise exposure measurement requires unique methods than those used for other sources of community noise.
194

Multibody Dynamics Using Conservation of Momentum with Application to Compliant Offshore Floating Wind Turbines

Wang, Lei 2012 August 1900 (has links)
Environmental, aesthetic and political pressures continue to push for siting off-shore wind turbines beyond sight of land, where waters tend to be deeper, and use of floating structures is likely to be considered. Savings could potentially be realized by reducing hull size, which would allow more compliance with the wind thrust force in the pitch direction. On the other hand, these structures with large-amplitude motions will make dynamic analysis both more challenging and more critical. Prior to the present work, there were no existing dynamic simulation tools specifically intended for compliant wind turbine design. Development and application of a new computational method underlying a new time-domain simulation tool is presented in this dissertation. The compliant floating wind turbine system is considered as a multibody system including tower, nacelle, rotor and other moving parts. Euler's equations of motion are first applied to the compliant design to investigate the large-amplitude motions. Then, a new formulation of multibody dynamics is developed through application of the conservation of both linear momentum and angular momentum to the entire system directly. A base body is prescribed within the compliant wind turbine system, and the equations of motion (EOMs) of the system are projected into the coordinate system associated with this body. Only six basic EOMs of the system are required to capture 6 unknown degrees of freedom (DOFs) of the base body when mechanical DOFs between contiguous bodies are prescribed. The 6 x 6 mass matrix is actually composed of two decoupled 3 x 3 mass matrices for translation and rotation, respectively. Each element within the matrix includes the inertial effects of all bodies. This condensation decreases the coupling between elements in the mass matrix, and so minimizes the computational demand. The simulation results are verified by critical comparison with those of the popular wind turbine dynamics software FAST. The new formulation is generalized to form the momentum cloud method (M- CM), which is particularly well suited to the serial mechanical N-body systems connected by revolute joints with prescribed relative rotation. The MCM is then expanded to multibody systems with more complicated joints and connection types.
195

Noise from wind turbines /

Fégeant, Olivier, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Tekn. högsk., 2001. / Härtill 7 uppsatser.
196

'Part of the solution' : developing sustainable energy through co-operatives and learning /

Duguid, Fiona C. B., January 2007 (has links)
Thesis (Ph. D.)--University of Toronto, 2007. / Source: Dissertation Abstracts International, Volume: 68-06, Section: A, page: 2278. Includes bibliographical references (leaves 173-185).
197

Smart Composites evaluation of embedded sensors in composite materials /

Palmer, Nathan Reed. January 2009 (has links) (PDF)
Thesis (MS)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: Douglas S. Cairns. Includes bibliographical references (leaves 138-143).
198

Frequency and voltage control of a high-penetration, no-storage wind-diesel system /

Tomilson, Andrew G., January 1998 (has links)
Thesis (M. Eng.), Memorial University of Newfoundland, 1998. / Bibliography: leaves 169-176.
199

Έλεγχος στροφών επαγωγικής μηχανής δακτυλιοφόρου δρομέα διπλής τροφοδοσίας : μια εναλλακτική προσέγγιση

Βαγγέλης, Φώτιος 05 March 2012 (has links)
Στην παρούσα διπλωματική εργασία παρουσιάζεται μια νέα προσέγγιση της επαγωγικής μηχανής δακτυλιοφόρου δρομέα που χρησιμοποιείται σε συστήματα ανεμογεννητριών. Αρχικά γίνεται μια σύντομη παρουσίαση των ανανεώσιμων πηγών ενέργειας και ειδικότερα της αιολικής ενέργειας. Παρουσιάζονται τα είδη των ανεμογεννητριών και τα συστήματα κινητήρων που χρησιμοποιούνται σε αυτές και ακολουθεί η ταξινόμηση, η ανάλυση και ο διανυσματικός έλεγχος του μετατροπέα προς την πλευρά του δικτύου και προς την πλευρά του δρομέα της επαγωγικής γεννήτριας διπλής τροφοδοσίας (DFIG). Τέλος μελετάται μια εναλλακτική προσέγγιση της επαγωγικής μηχανής ελεγχόμενου δρομέα και στάτη από τριφασικό μετατροπέα και ακολουθεί η προσομοίωση των εξισώσεων του συστήματος με τη βοήθεια του Matlab. / This thesis presents a new approach of the wound rotor induction machine used in wind turbine systems. First we make a brief presentation of renewable energies and especially of the wind energy. We present the kinds of wind turbines and engine systems used in them, followed by classification, analysis and vector control of the inverter on the side of the grid and to the side of the rotor of double fed induction generator (DFIG). Finally, we study an alternative approach of the induction machine controlled by rotor and stator of a three-phase converter, followed by the simulation of the equations of the system with the help of Matlab.
200

Ανάλυση και έλεγχος αιολικού συστήματος παραγωγής ηλεκτρικής ενέργειας με ασύγχρονη μηχανή

Μπουγά, Βασιλική 14 February 2012 (has links)
Η παρούσα διπλωματική εργασία πραγματεύεται τη μελέτη μιας διάταξης ανεμογεννήτριας με επαγωγική μηχανή βραχυκυκλωμένου κλωβού η οποία συνδέεται μέσω dc διασύνδεσης με το δίκτυο. Τη dc διασύνδεση τη δημιουργεί ένας dc πυκνωτής και από την πλευρά της μηχανής υπάρχει ένας ac/dc πλήρως ελεγχόμενος ανορθωτής ισχύος ενώ από την πλευρά του δικτύου βρίσκεται ένας dc/ac πλήρως ελεγχόμενος αντιστροφέας ισχύος. Σκοπός της εργασίας είναι αρχικά να μελετήσουμε θεωρητικά το συνολικό σύστημα της ανεμογεννήτριας χρησιμοποιώντας το μετασχηματισμό Park για τη μοντελοποίηση του στο d-q πλαίσιο αναφοράς. Στη συνέχεια προχωρούμε στον υπολογισμό των εξισώσεων στο χώρο κατάστασης και τέλικά προτείνουμε ένα σύστημα ελέγχου το οποίο βασίζεται στους PI ελεγκτές. Τέλος, προσομοιώνουμε το παραπάνω σύστημα με τη βοήθεια της εφαρμογής Simulink του λογισμικού Matlab και μελετώντας τα αποτελέσματα, εξάγουμε τα ανάλογα συμπεράσματα. / The present thesis deals with the study of provision of wind generator with inductive machine of which is connected via dc interconnection with the network. A dc capacitor creates the dc interconnection with the network.The aim of this work is initially to study theoretically the total system of wind generator using the transformation Park for its modelling in the d-q frame of report. Afterwards we advance in the calculation of equations in the space of situation and finally we propose a system of control which is based on PI controllers. Finally, we simulate the system with the help of the Simulink application of Matlab and studying the results, we export the proportional conclusions.

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