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1
Sarkar, Mustafa. "The assessment of psychological resilience in sport performers." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/17616.
Повний текст джерелаАнотація:
Why is it that some athletes are able to withstand the pressures of competitive sport and attain peak performances, whereas others succumb to the demands and under-perform? It is the study of psychological resilience that aims to address this question. To significantly advance psychologists' knowledge and understanding of this area, there exists an urgent need to develop a sport-specific measure of resilience (Fletcher & Sarkar, 2012; Galli & Vealey, 2008; Gucciardi, Jackson, Coulter, & Mallett, 2011). The purpose of this thesis, therefore, is to investigate the assessment of psychological resilience in sport performers. To this end, the thesis is split into five chapters. Chapter one reviews and critiques the various definitions, concepts, and theories of resilience, and provides an overview of the research that has specifically examined psychological resilience in sport performers. Chapter two reviews psychometric issues in resilience research and its implications for sport psychology (part one), and discusses psychological resilience in sport performers via a review of the stressors athletes encounter and the protective factors that help them withstand these demands (part two). Drawing on these reviews of resilience in sport, Chapter three (studies one-three) describes the development and validation of the Sport Resilience Scale (SRS). More specifically, Study 1 explores the content validity of a pool of items designed to reflect psychological resilience in athletes, Study 2 examines the factorial structure of the SRS using exploratory factor analysis, and Study 3 tests the factorial structure of the SRS via confirmatory factor analysis, investigates whether the components of the measurement model are invariant across different groups, and examines the relationship between the SRS and other relevant concepts. Using the SRS, and based on Fletcher and Sarkar's (2012) grounded theory of psychological resilience, Chapter four (studies 4 and 5) investigates resilience in sport performers via an examination of moderation and mediation hypotheses. Specifically, Study 4 tests whether the association between the stressors athletes encounter and athletes' positive adaptation is moderated by the protective factors that athletes possess and Study 5 tests whether the association between the stressors athletes encounter and athletes' positive adaptation is mediated by their cognitive appraisal processes. Lastly, Chapter five offers a summary, discussion, and conclusion of the thesis. Overall, the research reported in this thesis has developed the first valid and reliable measure of psychological resilience in sport performers and has provided quantitative support for Fletcher and Sarkar's (2012) theoretical model of sport resilience by illustrating the moderating role of protective factors and the mediating role of cognitive appraisal.
2
Frňka, Tomáš. "Bezdotykové měření povrchových teplot ve strojírenství." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228826.
Повний текст джерелаАнотація:
The subject of this thesis is the incorporation of the contactless temperature measurement of surface temperatures among other methods of temperature measurement with the analysis of (individual) advantages and disadvantages. The study is focused on the measurement and finding alternative protective clingfilms for thermo camera “Flir SC2000” and possible ways of their usage.
3
Al-Busaidi, Adil S. "Toward a Model of Organizational Muted Dissent: Construct Definition, Dimensions, Measurement, and Validation." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1407242598.
Повний текст джерела
4
Merkle, Shannon L. M. "Exploring pain & movement relationships: is greater physical activity associated with reduced pain sensitivity & does endogenous muscle pain alter protective reflexes in the upper extremity?" Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2245.
Повний текст джерелаАнотація:
Pain and movement are intimately connected and nearly universal human experiences. However, our understanding of the extent, significance, and mechanisms of pain-movement relationships is limited. While pain is a normal, protective response to injury and potentially harmful stimuli, prolonged or dysfunctional neuromuscular adaptions in response to pain can contribute to a variety of pain conditions. Alternatively, movement (in the form of global physical activity, individual exercise programs, and/or specific motor learning/functional tasks) is often prescribed to help decrease pain and improve function. While attempts have been made to show an effect of movement on pain or to better understand altered movement strategies in response to pain, much of the research has been limited to animal models or to those with specific persistent or chronic pain conditions limiting generalizability and interpretability. Therefore, this research sought to advance current understanding of the relationships between physical activity and normal variability in centrally- and peripherally-mediated pain in healthy adults. Additionally, we sought to characterize changes in reflexive motor responses in the upper extremity to an endogenous, naturally-occurring, long-lasting acute muscle pain.
The results of these investigations indicate that greater, self-reported intense (i.e. vigorous) and leisure activity are more strongly associated with decreased pain sensitivity than is pain modulation or measured activity (via accelerometry). Future research is needed to determine directionality of these relationships. Further, reflexive motor responses to endogenous, acute muscle pain in the upper extremity were not significantly altered indicating that changes in pain-related, movement strategies may be more strongly influenced by supraspinal adaptations. These results may have value in improving understanding of pain-related, movement sequelae and directing future research in this area.
5
Bálint, Zoltán. "Průvlekový transformátor proudu 25 kV, 400/5/5 A." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217917.
Повний текст джерелаАнотація:
The aim of this master’s thesis is the design of a double-core bushing-type current transformer. This appliance is intended for measuring and protection of high-voltage distribution systems of the internal type for the highest system voltage of 25 kV. The master’s thesis is divided into four parts. The first part describes the function of the current transformer. The next part deals with the analysis of the phasor diagram and errors of the current transformer. The major part of the thesis deals with the design of the protective and measuring core. The last part describes the 3D model of the bushing-type current transformer.
6
Quint, Ryan David. "Practical Implementation of a Security-Dependability Adaptive Voting Scheme Using Decision Trees." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/35667.
Повний текст джерелаАнотація:
Todayâ s electric power system is operated under increasingly stressed conditions. As electrical demand increases, the existing grid is operated closer to its stable operating limits while maintaining high reliability of electric power delivery to its customers. Protective schemes are designed to account for pressures towards unstable operation, but there is always a tradeoff between security and dependability of this protection.
Adaptive relaying schemes that can change or modify their operation based on prevailing system conditions are an example of a protective scheme increasing reliability of the power system. The purpose of this thesis is to validate and analyze implementation of the Security-Dependability Adaptive Voting Scheme. It is demonstrated that this scheme can be implemented with a select few Phasor Measurement Units (PMUs) reporting positive sequence currents to a Phasor Data Concentrator (PDC). At the PDC, the state of the power system is defined as Stressed or Safe and a set of relays either vote or perform normal operation, respectively.
The Adaptive Voting Scheme was implemented using two configurations: hardware- and software-based PDC solutions. Each was shown to be functional, effective, and practical for implementation. Practicality was based on the latency of Wide Area Measurement (WAM) devices and the added latency of relay voting operation during Stressed conditions. Phasor Measurement Units (PMUs), Phasor Data Concentrators (PDCs), and relay operation delays were quantified to determine the benefits and limitations of WAMS protection and implementation of the voting scheme. It is proposed that the delays injected into the existing protection schemes would have minimal effect on the voting scheme but must be accounted for when implementing power system controls due to the real-time requirements of the data.Master of Science
7
Hoang, Van Hung. "Electrochemical Synthesis of Novel Polyaniline-Montmorillonite Nanocomposites and Corrosion Protection of Steel." Doctoral thesis, Universitätsbibliothek Chemnitz, 2007. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200700059.
Повний текст джерелаАнотація:
This dissertation describes a new electrochemical synthesis of novel composite materials based on montmorillonite (MMT) clay and intrinsically conducting polyaniline (PANI). PANI was successfully incorporated into MMT galleries to form PANI−MMT nanocomposites. Electropolymerization of anilinium ions which are intercalated inside the clay layers have been carried out at a constant applied potential. The synthetic conditions have been optimized taking into account the effect of concentration of aniline, magnetic stirring and potential cycling. The resulting organic-inorganic hybrid material, PANI-MMT has been characterized by various physicochemical techniques. Results of elemental analysis show that nanocomposite contains only 10 % of conducting PANI. Formation of PANI inside the clay tactoid has been confirmed by the expansion of inter layer distance of MMT as revealed by X-ray diffraction studies. Relatively lower interlayer expansion for PANI-MMT than that of anilinium-MMT indicates the higher stereoregularity in PANI-MMT which has strong influence on electrical properties of nanocomposites. Infrared spectroscopy studies reveal the presence of physicochemical interaction, probably hydrogen bonding, between clay and polyaniline. Cyclic voltammetry studies indicate that presence of electroinactive clay does not influence the electrochemical activity of PANI. Electrochromic behaviour of PANI-MMT nanocomposites have been studied using in situ UV-Vis spectroscopy which reveals that electrochromism of PANI in the composite material has been retained. One of the main technological applications of conducting polymers, particularly PANI, is in the area of corrosion protection of active metals. PANI-MMT nanocomposites synthesized using the present method and a chemically synthesized PANI which is soluble in organic solvents have been used to protect C45 steel surface against corrosion. Corrosion studies have been performed using electrochemical impedance measurements(EIM)and anodic polarization studies. Electrochemical impedance data has been analyzed using a suitable equivalent circuit. Corrosion protection of steel offered by both PANI-MMT and organically soluble PANI is evident form the increase in the value of charge transfer resistance of the coated steel surfaces. Time dependent EIM measurements reveal that charge transfer resistance gradually decreases with time, however, the values are much higher than that of uncoated surfaces. Two capacitive loops, one at higher and another at lower frequencies, observed in the Nyquist plots have been assigned to the electrical properties of coating material (in the present case, PANI-MMT or soluble PANI) and electrochemical process at the interface, respectively. An anodic shift in the corrosion potential, a decrease in the corrosion rate and a significant increase in the polarization resistance indicate a significant anti-corrosion performance of both PANI-MMT nanocomposite and organically soluble PANI deposited on the protected steel surfaceDiese Dissertation beschreibt eine neue elektrochemische Synthese neuartiger Compositmaterialien basierend auf dem Tonmineral Montmorillonite (MMT) und intrinsisch leitfähigem Polyanilin (PANI). Die Elektropolymerisation von Aniliniumionen, welche in die Tonmineralschichten eingebaut sind, wurde bei einem konstanten Potenzial durchgeführt. Das resultierende organisch-anorganische Hybridmaterial PANI-MMT wurde mit verschiedenen physikochemischen Methoden charakterisiert. Die Ergebnisse der Elementaranalyse zeigen, dass nur 10 % des Nanocompositmaterials aus leitfähigem PANI bestehen. Die Vergrößerung des Zwischenschichtabstandes von MMT, die bei Röntgendiffraktometrieuntersuchungen beobachtet wurde, lässt auf die Bildung von PANI innerhalb der Tonmineral-Taktoide schließen. IR-spektroskopische Untersuchungen deuten auf das Vorhandensein von Wechselwirkungen physikochemischer Art, wahrscheinlich Wasserstoffbindungen zwischen dem Tonmineral und Polyanilin, hin. Untersuchungen mit zyklischer Voltammetrie zeigten, dass die Anwesenheit von elektroinaktivem Tonmineral die elektrochemische Aktivität von PANI nicht beeinflusst. Das elektrochrome Verhalten von PANI-MMT Nanocompositen wurde mit UV-Vis-Spektroskopie untersucht, wobei sich herausstellte, dass das elektrochrome Verhalten vom PANI im Compositmaterial erhalten bleibt. Eines der technologischen Hauptanwendungsgebiete von leitfähigen Polymeren, insbesondere von PANI, ist der Korrosionsschutz von aktiven Metallen. PANI-MMT Nanocomposite die mit der angegebenen Methode (elektrochemisch) synthetisiert wurden und chemisch synthetisiertes in organischen Medien lösliches PANI wurden zum Korrosionsschutz von C45 Stahl eingesetzt. Die Korrosionsuntersuchungen wurden mit Hilfe von elektrochemischen Impedanzmessungen (EIM) und anodischen Polarisationsuntersuchungen durchgeführt. Der von PANI-MMT und von in organischen Medien löslichem PANI gebotene Korrosionsschutz ist wahrscheinlich auf die Zunahme des Ladungsdurchtritts widerstandes der beschichteten Stahloberfläche zurückzuführen. Die anodische Verschiebung des Korrosionspotenzials, eine Verringerung der Korrosions-geschwindigkeit und eine deutliche Zunahme des Polarisationswiderstandes sind eindeutige Hinweise für das Antikorrosionsvermögen von PANI-MMT und auch von in organischen Medien löslichem PANI, welche auf der zu schützenden Stahloberfläche abgeschieden wurden
8
Jalandoni, D. Jay Moreno. "In-phantom measurement of HE or neutron protection dosimetry." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/16777.
Повний текст джерела
9
Tania, Mutmainna. "Wide Area Measurement Applications for Improvement of Power System Protection." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/19241.
Повний текст джерелаАнотація:
The increasing demand for electricity over the last few decades has not been followed by adequate growth in electric infrastructure. As a result, the reliability and safety of the electric grids are facing tremendously growing pressure. Large blackouts in the recent past indicate that sustaining system reliability and integrity turns out to be more and more difficult due to reduced transmission capacity margins and increased stress on the system. Due to the heavy loading conditions that occur when the system is under stress, the protection systems are susceptible to mis-operation. It is under such severe situations that the network cannot afford to lose its critical elements like the main generation units and transmission corridors.In addition to the slow but steady variations in the network structure over a long term, the grid also experiences drastic changes during the occurrence of a disturbance. One of the main reasons why protection relays mis-operate is due to the inability of the relays to adjust to the evolving network scenario. Such failures greatly compound the severity of the disturbance, while diminishing network integrity leading to catastrophic system-wide outages. With the advancement of Wide Area Measurement Systems (WAMS), it is now possible to redesign network protection schemes to make them more adaptive and thus improve the security of the system.
Often flagged for exacerbating the events leading to a blackout, the back-up distance protection relay scheme for transmission line protection and the loss-of-field relay scheme for generator unit protection can be greatly improved from an adaptability-oriented redesign. Protection schemes in general would benefit from a power re-distribution technique that helps predict generator outputs immediately after the occurrence of a contingency.
Ph. D.
10
Cong, Yuhang. "Synchronized measurement technology supported operational tripping schemes." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/synchronized-measurement-technology-supported-operational-tripping-schemes(7d472659-d352-4291-96fc-fce7e6ce5fc8).html.
Повний текст джерелаАнотація:
The increasing volume of renewable and intermittent generation that is being connected to power systems means that system operators need more advanced dynamic control tools to manage the increase in congestion and the resulting pressure on system constraints. The introduction of synchronised measurement technology provides the wide area real-time measurements that are essential to develop and implement adaptive online solutions for current network issues. The objective of the research presented in this thesis is to design intelligent system integrity protection schemes (SIPS) that protect transmission lines and power transformers from thermal overloading. An intelligent protection scheme should be able to identify the fault severity, predict the post disturbance trend of system states, continue monitoring specific vulnerable system variables and propose an accurate solution that is tailored to the actual system conditions and the specific contingencies that have occurred. The intent of this research is to contribute to the development of adaptive protective schemes that are enabled by modern synchronized measurement technologies for future power systems. The research presented in this thesis focuses on the creation of novel Operational Tripping Schemes (OTSs) that explicitly satisfy both the functionality and economical requirements by integrating an improved assessment of thermal behaviour of the monitored assets. Novel OTSs are proposed for both transmission lines and transformers and they can be considered to be intelligent, adaptive and efficient SIPS for the thermal protection of system assets. A novel functional block is proposed that be included within the OTS and that uses optimization theory to determine the lowest cost solution to overheating in the time available. Furthermore, case studies have been conducted to verify the performance of each novel OTS using simulations of a full GB system model.
11
Huang, Chiung-Yi. "The application of phasor measurements for adaptive protection and control." Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/42131.
Повний текст джерелаАнотація:
This thesis describes an adaptive protection scheme that performs the collection of the voltage and
current phasors during post-fault period, tracking the power swing phenomena, identifying the onset
of instability, and then issuing a stabilizing command. In this work, the protection system is to
maintain the reliability! ensure the secure operation, and prevent total collapse of the power system.
The work is based upon methods of clustering for meter placement in a bulk power system, and
selecting the pilot points for installing the phasor measurement units (PMU) to measure the bus
voltage phasors and associated branch current phasors. According to the network law, fast calculation
of state estimation can be made from these measurements. Because the on-line assessment
of transient stability has to provide a quick and approximate result, the direct method which determines
stability without explicit integration techniques is applicable in this study.
The results of the system stability prediction in real-time by digital computer simulation under
stable and unstable operating conditions are presented.
Master of Science
12
Adewole, Adeyemi Charles. "Voltage stability assessment and wide area protection/control using synchrophasor measurements." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2380.
Повний текст джерелаАнотація:
Thesis (DTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016.Electric power systems are being operated closer to their designed stability limits due to the constraints caused by the continuous increase in system loading, and the lack of new power stations and transmission network infrastructure to support this increase in system loading. This coupled with the practice of long distance bulk power transmission and cascading contingencies, makes system instability and consequently blackouts inevitable. In such scenarios, system instabilities like voltage instability becomes a serious threat to the secure operation of the power system, and voltage collapse (system-wide blackouts) are prone to occur. This is often compounded by the unavailability of real-time system measurements for situational awareness from the existing Supervisory Control and Data Acquisition (SCADA)/Energy Management System (EMS) platforms which are usually based on unsynchronized SCADA measurements with a slow reporting rate of 1 measurement every 2-10 seconds. This Doctoral thesis proposes non-iterative algorithms and methods of solution based on the IEEE C37.118 synchrophasor measurements from Phasor Measurement Units (PMUs) with a high reporting rate of up to 200 measurements every second (200 fps) for voltage stability assessment and automated wide area Centralised Protection/Control (CPC) against catastrophic voltage instabilities/blackouts in power systems. Extended formulations are proposed for the Optimal Placement of PMUs (OPP) in power systems with respect to voltage stability assessment. The impact of zero injection buses, critical buses, and PMU redundancy is considered in the formulation of the OPP problem solution. The extended formulations made use of Binary Integer programming (BIP) and Modal Participation Factors (MPFs) derived from the eigenvalues of the power flow Jacobian.
13
Elayyan, H. S. B. "Protection of high voltage systems against surge voltages : New models and measurement techniques." Thesis, Cardiff University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378453.
Повний текст джерела
14
Pal, Anamitra. "PMU-Based Applications for Improved Monitoring and Protection of Power Systems." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/51093.
Повний текст джерелаАнотація:
Monitoring and protection of power systems is a task that has manifold objectives. Amongst others, it involves performing data mining, optimizing available resources, assessing system stresses, and doing data conditioning. The role of PMUs in fulfilling these four objectives forms the basis of this dissertation. Classification and regression tree (CART) built using phasor data has been extensively used in power systems. The splits in CART are based on a single attribute or a combination of variables chosen by CART itself rather than the user. But as PMU data consists of complex numbers, both the attributes, should be considered simultaneously for making critical decisions. An algorithm is proposed here that expresses high dimensional, multivariate data as a single attribute in order to successfully perform splits in CART.
In order to reap maximum benefits from placement of PMUs in the power grid, their locations must be selected judiciously. A gradual PMU placement scheme is developed here that ensures observability as well as protects critical parts of the system. In order to circumvent the computational burden of the optimization, this scheme is combined with a topology-based system partitioning technique to make it applicable to virtually any sized system.
A power system is a dynamic being, and its health needs to be monitored at all times. Two metrics are proposed here to monitor stress of a power system in real-time. Angle difference between buses located across the network and voltage sensitivity of buses lying in the middle are found to accurately reflect the static and dynamic stress of the system. The results indicate that by setting appropriate alerts/alarm limits based on these two metrics, a more secure power system operation can be realized.
A PMU-only linear state estimator is intrinsically superior to its predecessors with respect to performance and reliability. However, ensuring quality of the data stream that leaves this estimator is crucial. A methodology for performing synchrophasor data conditioning and validation that fits neatly into the existing linear state estimation formulation is developed here. The results indicate that the proposed methodology provides a computationally simple, elegant solution to the synchrophasor data quality problem.Ph. D.
15
Wrinch, Michael C. "Negative sequence impedance measurement for distributed generator islanding detection." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/3418.
Повний текст джерелаАнотація:
This thesis presents a method of detecting electrical islands in low voltage distributed generator networks by measuring negative sequence impedance differences between islanded and utility connections. Extensive testing was conducted on a commercial building and 25 kV distributed generator fed network by measuring naturally occurring and artificially injected negative sequence components. Similarly, this technique was tested using the IEEE 399-1990 bus test case using the EMTP software. The practical measurements have been matched to simulations where further system performance characteristics of detecting power system islands has been successfully demonstrated. Measured results indicate that unbalanced load conditions are naturally occurring and readily measurable while deliberately unbalanced loads can increase the accuracy of negative sequence impedance islanding detection. The typically low negative sequence impedance of induction motors was found to have only a small effect in low voltage busses, though large machines can effect the threshold settings. Careful placement of the island detector is required in these situations. The negative sequence impedance measurement method is an improvement on previous impedance measurement techniques for islanding detection due to its accuracy, and distinctly large threshold window which have challenged previous impedance based islanding detection techniques.
16
Mthunzi, Everett Mondliwethu. "Performance analysis of a protection scheme based on P-class synchrophasor measurements." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2378.
Повний текст джерелаАнотація:
Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016.Power grid and system protection advancement greatly depend on technological advances. Advent technologies like digital microprocessor type protective relays facilitate paradigm shifts, providing inimitable beneficial engineering adaptations. Phasor measuring technology provides one such technological advance. The onset and rapid development of the Phasor Measuring Unit (PMU) provides an excellent platform for phasor-based, power system engineering. Power transmission constitutes a critical section in the electric power system. The power system transmission lines are susceptible to faults which require instant isolation to establish and maintain consistent system stability. This research focuses on the study of transmission line protection based on P-Class synchrophasor measurements. The IEEE C37.238-2011 Precision Time Protocol (PTP) paradigm shift facilitates practical application of synchrophasors in protection schemes. Synchrophasor procession and accurate data alignment over wide areas support the hypothesis of a phasor-based transmission line differential protection. This research aims to directly implement P-Class synchrophasors in transmission line differential protection, employing synchrophasors to determine fault conditions and administer corresponding protective actions in wide area transmission lines. The research also aims to evaluate the operational characteristics of the synchrophasor-based transmission line differential protection scheme. The research deliverables include a laboratory scale Test-bench that implements the PMU-based transmission line differential protection scheme, and a differential protection utility software solution that follows guidelines specified by the C37.118-2011 standard for synchrophasors. The findings stand to evaluate performance of the PMU-based line differential protection scheme, verifying the protection model as an alternate, practical and feasible backup protection solution. The research deliverables include a synchrophasor-based current differential algorithm, software utility for implementing the PMU-based protection scheme and a Test-bench for concept and feasibility validation.
17
Mauney, Daniel W. "Investigation of physical and psychophysical methods for the attenuation measurement of circumaural hearing protectors with implication for field use." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/40073.
Повний текст джерелаАнотація:
A field-implementable measure is needed to estimate the attenuation workers are
achieving with their hearing protectors in the field. Alternative measures for assessing a
hearing protector's effectiveness were evaluated through comparison to the standardized
real-ear attenuation at threshold (REAT) method, termed 1I3-REAT, a psychophysical
procedure (ANSI S3.19-1984). One alternative deviated from the standardized procedure
primarily through utilizing a pure-tone audiometer coupled to an amplifier and loudspeaker
for the sound field presentation of pure tones (Pr -REAT). The other alternative. tenned
microphone in real-ear (MIRE), used miniature microphones in each concha and just
outside of each of the subject's two ears to physically measure the attenuation of the
protector using both insertion loss (lL-MIRE) and noise reduction (NR-MIRE) procedures.
Comparisons between the alternative measures were made across nine 113 octave bands
centered at 125, 250, 500, 1000, 2000, 3150,4000, 6300, and 8000 Hz. The experiment
also explored a means for predicting broadband attenuation from data of a single 113 octave
band through a regression analysis for both PT -REAT tests and NR-MIRE tests.
Results showed that when comparing the PT -REAT test and the standardized 1/3-
REA T method, the standardized method exhibited significantly greater attenuation at most
of the 1/3 octave bands tested. The difference, however, may be due to the higher ambient
noise levels present in the pure tone condition. The MIRE measures also showed some
significant differences with the standardized 1/3-REAT method for the values collapsed
across protectors, with the direction of the difference changing with test band. At 125 Hz,
the MIRE metrics yielded significantly lower attenuation, while from 500 to 6300 Hz, the
1/3-REAT method generally yielded significantly lower attenuation. These differences may
be due in part to the occlusion effect and the bone conduction of sound. In general,
however, the size and consistency of the differences across hearing protection devices
(HPDs) suggest that PT-REAT and MIRE measures hold promise for providing quick and
relatively accurate estimations of an HPD's attenuation in the field. Results of the
regression analyses indicated that single test band data obtained at 250 and 500 Hz, from
both PT-REAT and NR-MIRE metrics, provided the best predictions for the hearing
protectors tested in this study, based on their Pearson product-moment correlation
coefficients.Ph. D.
18
Roscoe, Andrew. "Measurement, control and protection of microgrids at low frame rates supporting security of supply." Thesis, University of Strathclyde, 2009. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=23787.
Повний текст джерелаАнотація:
Increasing penetrations of distributed generation at low power levels within electricity networks leads to the requirement for cheap, integrated, protection and control systems. To minimise unit cost, algorithms for the measurement of AC voltage and current waveforms should be implemented on a single microcontroller, which also carries out all other protection and control tasks, including communication and data logging. This limits the frame rate of the major algorithms, although ADCs can be over-sampled using peripheral control processors on suitable microcontrollers. Measurement algorithms also have to be tolerant of poor power quality which may arise, even transiently, within a microgrid, battlefield, or disaster-relief scenario. This thesis analyses the potential magnitude of these interfering signals, and presents suitably tolerant architectures and algorithms for measurements of AC waveforms (amplitude, phase and frequency). These algorithms are shown to be robust and accurate, with harmonic content up to the level of 53% THD, and with the major algorithms executing at only 500 samples per second. This is achieved by the careful optimisation and cascaded use of exact-time averaging techniques, which prove to be useful at all stages of the measurements: from DC bias removal to low-sample-rate Fourier analysis to sub-harmonic ripple removal. Algorithms for three-phase nodal power flow analysis are benchmarked on the Infineon TC1796 microcontroller and require less than 8% of the 2000ps frame time, leaving the remainder free for other algorithms.
19
Lu, Zhen. "Development of advanced power system protection and power quality measurement algorithms using mathematical morphology." Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433041.
Повний текст джерела
20
Fan, Dawei. "Synchronized Measurements And Applications During Power System Dynamics." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26115.
Повний текст джерелаАнотація:
Synchronized phasor measurements during dynamics tend to be affected by prevailing system frequency. Some major blackouts in power systems are indeed featured with very large frequency disturbance. Quantitative study done in this dissertation shows that small frequency disturbance may lead to measurement errors, and large frequency disturbance may lead to wrong measurements as well as catastrophic results if applied in system protection and control. The purpose of this dissertation is to bring up this issue, point to some possible solutions and application examples.
A synchronized frequency measurement method, which has better dynamic performance, is proposed in this dissertation. Based on this accurate synchronized frequency, a phasor compensation algorithm is proposed to correct the errors due to frequency disturbance in legacy PMUs or as alternative frequency tracking algorithm in new PMUs. Phasor positioning and unbalance issues are also investigated in this dissertation. With these improved synchronized measurements, wide area protection and control can be achieved with higher reliability. As an application example, traditional preset out-of-step protection could be replaced by the adaptive out-of-step protection using wide area measurements. Real-time swing curve and real-time EEAC based adaptive out-of-step protection schemes are developed respectively in this dissertation. Numerical Simulations are performed for validation of the proposed concepts.Ph. D.
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Ejenstam, Lina. "Hydrophobic and superhydrophobic coatings for corrosion protection of steel." Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175405.
Повний текст джерелаАнотація:
Since metals in general, and steels in particular, are vital construction materials in our modern society, the corrosion protection of said materials is of great importance, both to ensure safety and to reduce costs associated to corrosion. Previously, chromium (VI) and other harmful substances were effectively used to provide corrosion protection to steel, but since their use was heavily regulated around year 2000, no coating has yet been developed that, in a fully satisfactory manner, replaces their corrosion protective properties.In this thesis, the use of hydrophobic and superhydrophobic surface coatings as part of corrosion protective coating systems has been studied. Since the corrosion mechanism relies on the presence of water to take place, the use of a superhydrophobic coating to retard the penetration of water to an underlying metal surface is intuitive. The evaluation of corrosion protective properties of the hydrophobic and superhydrophobic surfaces was performed using mainly contact angle measurements and electrochemical measurements in severely corrosive 3 wt% NaCl water solution.First, the differences in corrosion protection achieved when employing different hydrophobic wetting states were investigated using a model alkyl ketene dimer wax system. It was found that superhydrophobicity in the Lotus state is superior to the other states, when considering fairly short immersion times of less than ten days. This is due to the continuous air film that can form between such a superhydrophobic surface and the electrolyte, which can retard the transport of electrolyte containing corrosive ions to the metal surface to the point where the electrical circuit is broken. Since corrosion cannot occur unless an electrical current is flowing, this is a very efficient way of suppressing corrosion.An air layer on an immersed superhydrophobic surface is, however, not stable over long time, and to investigate long-term corrosion protection using hydrophobic coatings a polydimethylsiloxane formulation containing hydrophobic silica nanoparticles was developed. This system showed enhancement in corrosion protective properties with increasing particles loads, up until the point where the particle load instead causes the coating to crack (at 40 wt%). The conclusion is that the hydrophobicity of the matrix and filler, in combination with the elongatedivdiffusion path supplied by the addition of particles, enhanced the corrosion protection of the underlying substrate.To further understand how hydrophobicity and particle addition affect the corrosion protective properties of a coating a three layer composite coating system was developed. Using this coating system, consisting of a polyester acrylate base coating, covered by TiO2 particles (with diameter < 100 nm) and finally coated with a thin hexamethyl disiloxane coating, it was found that both hydrophobicity and particles are needed to reach a great enhancement in corrosion protective properties also for this system.Eftersom metaller, och då särskilt stål, är viktigta konstruktionsmaterial i vårt moderna samhälle är korrosionsskydd av stor betydelse, både för att garantera säkerhet och för att minska kostnader som uppkommer i samband med korrosion. Tidigare har sexvärt krom och andra skadliga ämnen använts för att på ett effektivt sätt skydda stål från korrosion, men efter att deras användning kraftigt reglerades runt år 2000 har ännu ingen beläggning utvecklats som helt kan ersätta krombeläggningarna med avseende på funktion.I denna avhandling har hydrofoba och superhydrofoba ytbeläggningar och deras möjliga applikation som en del av ett korrosionsskyddande beläggningssystem studerats. Eftersom korrosionsmekanismen är beroende av närvaron av vatten, är användandet av en superhydrofob beläggning för att fördröja transporten av vatten till den underliggande metallytan intuitiv. De korrosionsskyddande egenskaperna hos superhydrofoba ytbeläggningar utvärderades här främst med hjälp av kontaktvinkelmätningar och elektrokemisk utvärdering i korrosiv lösning bestående av 3 vikts% NaCl i vatten.Först undersöktes skillnaden i korrosionsskydd som uppnås vid användandet av ytbeläggningar med olika hydrofoba vätningsregimer med hjälp av ett modellsystem bestående av ett alkylketendimer vax. Det konstaterades att superhydrofobicitet i Lotusregimen är överlägset bättre än de andra hydrofoba vätningsregimerna, i alla fall när man ser till relativt korta exponeringstider, typiskt mindre än tio dagar. Detta beror på att den kontinuerliga luftfilm som kan bildas på en sådan typ av superhydrofob yta kan minska transporten av elektrolyt (som innehåller korrosiva joner) till metallytan till den grad att den elektriska kretsen bryts. Eftersom korrosion inte kan ske utan en sluten elektrisk krets är detta ett mycket effektivt sätt att förhindra korrosion från att ske.Ett luftskikt på en superhydrofob yta nedsänkt i vatten är dock inte stabilt under lång tid. För att undersöka möjligheten till korrosionsskydd under längre tid med hjälp av hydrofoba beläggningar utvecklades en hydrofob ytbeläggning bestående av polydimetylsiloxan och hydrofoba nanopartiklar av kiseldioxid. Detta system visade en förbättring av korrosionsskyddet vid ökat partikelinnehåll upp till den koncentration (40 wt%) där i stället sprickbildning i ytbeläggningen observerades. Från detta system kunde slutsatsen dras att matrisens och partiklarnasvihydrofobicitet i kombination med den längre diffusionsvägen som partiklarna orsakade förbättrade korrosionsskyddet av den underliggande metallen.För att ytterligare förstå hur hydrofobicitet och partikeltillsatser påverkar en ytbeläggnings korrosionsskyddande egenskaper har dessutom ett treskikts kompositbeläggningssystem utvecklats. Genom att använda detta beläggningssystem, som består av en basbeläggning av polyesterakrylat, ett lager TiO2-partiklar (med en diameter på <100 nm) slutligen belagt med ett tunt ytskikt bestående av hexametyldisiloxan så kunde slutsatsen dras att både en hydrofob matris och partiklar behövs för att nå en markant förbättring av ytbeläggningens korrosionsskyddande egenskaper.
QC 20151015
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Palizban, Atefeh. "Wide-area monitoring and control utilizing PMU measurements for a system protection scheme." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52888.
Повний текст джерелаАнотація:
The ever increasing complexity of the electrical grid has made it difficult to predict and anticipate contingencies. This is mainly due to the advent of deregulated electricity markets, aging transmission infrastructure and the growing penetration of renewable resources. The wave of blackouts in recent years has made utilities much more aware of the need for power system wide monitoring and control. One of the fundamental requirements to achieve that goal is to have common measurement reference. A few technology enablers have emerged which have led to development of a new kind of measurement paradigm; Phasor Measurement Units, or PMUs.
PMUs bear high potential for wide-area system monitoring and control as well for conducting advanced engineering analysis. PMUs can provide time-synchronized high-resolution estimates of voltage and currents (both phase amplitude and angle) as well as frequency and rate of change of frequency. Such measurements, alternatively called synchrophasors, can provide visibility of a power system distributed over a wide geographical area and can be utilized in a multitude of applications including real-time monitoring, advanced power system protection, and advanced control schemes.
In this thesis, a new special protection scheme (SPS) is proposed based on synchronized measurements provided by PMUs. An existing remedial action scheme (RAS) protecting for contingencies impacting the tie-line interconnecting the Alcan system to B.C. Hydro, using conventional relays is studied, and a new scheme based on time-synchronized, and high-resolution voltage angle measurements from PMU’s in a Wide-are monitoring system (WAMs) is proposed . In this new scheme, the angles of the buses at large power plants in both systems are examined and used to calculate various criteria based on region center of angle and the kinetic energy function to implement RAS.
The results of a number of time domain simulations demonstrate that the proposed scheme can lead to faster operation of the SPS and decreased amount of generation and load shedding in the Alcan system. The achieved speed and efficiency of the proposed scheme in comparison to the existing installed scheme further highlight the opportunity in utilizing PMU measurements in online applications for power system protection and monitoring.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Janssen, Pierre. "Monitoring, protection and fault location in power distribution networks using system-wide measurements." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209366.
Повний текст джерелаАнотація:
This work takes place in the context of distribution grids with high level of distributed generation, for example in microgrids. With high level of distributed generation, it has been shown that selective, fast and sensitive network protection is expected to be more difficult. Furthermore, during system restoration, the accurate fault location could be more challenging to assess, thereby increasing the average outage duration.Thanks to cost reductions and improvement of information and communication technologies, future distribution networks will probably have advanced communication infrastructures and more measurement devices installed in order to manage the increasing complexity of those networks, which is primarily caused by the introduction of distributed generation at the distribution level.
Therefore this thesis investigates how the monitoring, protection and fault location functions can be improved by using system-wide measurements, i.e. real-time measurements such as synchronized voltage and current measurements recorded at different network locations. Distributed synchronized measurements bring new perspectives for these three functions: protection and fault location are usually performed with local measurements only and synchronized measurements are not common in monitoring applications. For instance, by measuring distributed generators infeed together with some feeder measurements, the protection is expected to be more sensitive and selective and the fault location to be more accurate.
The main contribution of this work is the use of state estimation, which is normally only used for network monitoring, for the protection and the fault location.
The distribution system state estimation is first developed using the classical transmission system approach. The impact of the placement of the measurement devices and of a relatively low measurement redundancy on the accuracy, on the bad data detection and on the topology error identification capabilities of the estimator are discussed and illustrated. This results in recommendations on the placement of the meters.
Then, a backup protection algorithm using system-wide measurements is presented. The coherence of the measurements and the healthy network model are checked thanks to a linear three-phase state estimation. If the model does not fit to the measurements and if the estimated load is too high or unbalanced, a fault is detected. The advantages of the method are that the voltage measurement redundancy is considered, improving the detection sensitivity, and that load models may be considered in the algorithm, avoiding the need to install measurement devices on every line of the network.
Finally, two new impedance-based fault location algorithms using distributed voltage and current recordings are proposed. By defining statistical errors on the measurements and the network parameters, a method to compute a confidence interval of the fault distance estimate is proposed. The fault location accuracy and its sensitivity to the fault conditions (e.g. fault resistance or fault type) and to the different sources of error are assessed on a simulated distribution system.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Daggupati, Naga Prasad. "Assessment of the varitarget nozzle for variable rate application of liquid crop protection products." Thesis, Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/414.
Повний текст джерела
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Ho, Wing-kwok, and 何永國. "Solar ultraviolet radiation: monitoring, dosimetry and protection." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31222675.
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Oliver, Hannah Elizabeth. "The impacts of optical radiation in the environment on skin : hazards, measurement, regulation and protection." Thesis, Brunel University, 2006. http://bura.brunel.ac.uk/handle/2438/5329.
Повний текст джерелаАнотація:
From 2001 to 2005, work was conducted at the Photobiology Unit at Ninewells Hospital in Dundee to examine the optical radiation environment and its implications for normal and diseased skin. Artificial sources of radiation were considered within the contexts of the hazards posed, measurement of the hazards, regulation concerning exposure and sources, and protection of abnormal skin from adversee ffects. The hazards posed by both ultraviolet (UV) and visible polychromatic sources were examined for normal and abnormal (chronic actinic dermatitis and solar urticaria) skin in an effort to predict the responses to such radiation. With current methodologiesi t was shown that responsesto polychromatic light cannot be forecast for normal and abnormal skin. Those hazards posed by light sources in the commercial sector are also considered. The sunbeds available in Perthshire and Dundee were evaluated spectroradiometrically and appropriate weighting functions applied. A case of adverse effects due to inappropriate use of an UV source is also presented and the implications are discussed. Two diode array spectroradiometers were evaluated for their potential as instruments to measure UV sources. It was shown that one instrument could be used to give measurementsw ith acceptablee rrors. However, later work with a different instrument of the same series showed that there are manufacturing issues to be resolved before these instruments are marketed for widespread use in dosimetry. Regulations governing exposure to and use of sources are considered where appropriate. Licensing of commercial sunbed parlours is suggested in order to enforce Health and Safety guidelines and the British Standard for such appliances, create a baseline for minimum standards of care within the commercial sector and safeguard public health. Lastly, it has been shown that skin sensitive to visible light can be protected with commercial makeup preparations.
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Tanny, Sean M. "Investigation of Radiation Protection Methodologies for Radiation Therapy Shielding Using Monte Carlo Simulation and Measurement." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1449853114.
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Franzen-Korzendorfer, Holly. "Effects of monochromatic infrared energy on transcutaneous oxygen measurements in diabetic subjects with a loss of protective sensation." Diss., NSUWorks, 2006. https://nsuworks.nova.edu/hpd_pt_stuetd/15.
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Bernabeu, Emanuel. "Methodology for a Security-Dependability Adaptive Protection Scheme based on Data Mining." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/30131.
Повний текст джерелаАнотація:
The power industry is currently in the process of re-inventing itself. The unbundling of the traditional monopolistic structure that gave birth to a deregulated electricity market, the mass tendency towards a greener use of energy, the new emphasis on distributed generation and alternative renewable resources, and new emerging technologies have revolutionized the century old industry.
Recent blackouts offer testimonies of the crucial role played by protection relays in a reliable power system. It is argued that embracing the paradigm shift of adaptive protection is a fundamental step towards a reliable power grid. The adaptive philosophy of protection systems acknowledges that relays may change their characteristics in order to tailor their operation to prevailing system conditions. The purpose of this dissertation is to present methodology to implement a security/dependability adaptive protection scheme. It is argued that the likelihood of hidden failures and potential cascading events can be significantly reduced by adjusting the security/dependability balance of protection systems to better suit prevailing system conditions.
The proposed methodology is based on Wide Area Measurements (WAMs) obtained with the aid of Phasor Measurement Units (PMUs). A Data Mining algorithm known as Decision Trees is used to classify the power system state and to predict the optimal security/dependability bias of a critical protection scheme.Ph. D.
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NGUYEN, Ngoc Trung. "Study and development of innovative measurement methods and systems for anti-islanding protection in smart grids." Doctoral thesis, Università degli Studi di Palermo, 2014. http://hdl.handle.net/10447/90786.
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Bell, Kenneth Frazer. "Measurement of the deposition of aerosol particles to skin, hair and clothing." Thesis, Imperial College London, 1999. http://hdl.handle.net/10044/1/8608.
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Bogue, Jonathan Nelson. "Evaluation of Patient-Scatter Factors for Radiation Therapy ShieldingUsing Physical Measurement in a "Good" Geometry." University of Toledo Health Science Campus / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=mco1525447575821026.
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BOCK, III EDWARD LAWRENCE. "PRACTICALITY OF USING AIR LEAD MEASUREMENTS BY PORTABLE X-RAY FLUOURESCENCE TO MANAGE WORKER PROTECTION PROGRAMS." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1022196683.
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Seydaliev, Marat Radikovich. "Development and Test of a GEM-Based TEPC for Neutron Protection Dosimetry." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14607.
Повний текст джерелаАнотація:
The effective dose equivalent, H (or the effective dose, E ) to an individual is the primary limiting quantity in radiation protection. However, techniques for measuring H for neutrons have not been fully developed. In this regard a new tissue equivalent proportional counter (TEPC) based on a gas electron multiplier (GEM) for measuring H*(10), which is a conservative estimate of H, for neutrons was designed and constructed.
The deposited energy distribution for two different neutron sources (a Cf-252 source and a AmBe source) was measured using the new TEPC. The measurements were performed using two different proportional gases: P-10 gas and a propane-based tissue equivalent gas at various pressures. A computer simulation of the new TEPC, based on the Monte Carlo method, was performed in order to obtain the pulse height distributions for the two neutron sources. The simulated results and the measured results were compared. Results show that the experimental results agree with the computational results within 20% of accuracy for both Cf-252 and AmBe neutron sources.
A new model GEM-based TEPC was developed for use in obtaining H*(10). The value of H*(10) for the Cf-252 source and for the AmBe source using experimental measurements was obtained. These results are presented in this study. The study shows that the GEM-based TEPC can successfully estimate H*(10). With these results and some refinements, this GEM-based TEPC can directly be used as a neutron rem meter.
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Besar, Idris Bin. "Studies of the hazards of actinide contamination to man and methods of body measurement." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323396.
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Azzopardi, Alexander. "Measurement of erosion and protecting exposed dentine with an adhesive resin coating : an in-vitro and in-situ evaluation." Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394247.
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Szwer, David James. "High fidelity readout and protection of a 43Ca+ trapped ion qubit." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515002.
Повний текст джерелаАнотація:
This thesis describes theoretical and experimental work whose main aim is the development of techniques for using trapped 43Ca⁺ ions for quantum information processing. I present a rate equations model of 43Ca⁺, and compare it with experimental data. The model is then used to investigate and optimise an electron-shelving readout method from a ground-level hyperfine qubit. The process is robust against common experimental imperfections. A shelving fidelity of up to 99.97% is theoretically possible, taking 100 μs. The laser pulse sequence can be greatly simplified for only a small reduction in the fidelity. The simplified method is tested experimentally with fidelities up to 99.8%. The shelving procedure could be applied to other commonly-used species of ion qubit. An entangling two-qubit quantum controlled-phase gate was attempted between a 40Ca⁺ and a 43Ca⁺ ion. The experiment did not succeed due to frequent decrystallisation of the ion pair, and strong motional decoherence. The source of the problems was never identified despite significant experimental effort, and the decision was made to suspend the experiments and continue them in an improved ion trap which is under construction. A sequence of pi-pulses, inspired by the Hahn spin-echo, was derived that is capable of greatly reducing dephasing of any qubit. If the qubit precession frequency varies with time as an nth-order polynomial, an (n+1) pulse sequence is theoretically capable of perfectly cancelling the resulting phase error. The sequence is used on a 43Ca+ magnetic-field-sensitive hyperfine qubit, with 20 pulses increasing the coherence time by a factor of 75 compared to an experiment without any spin-echo. In our ambient noise environment the well-known Carr-Purcell-Meiboom-Gill dynamic-decoupling method was found to be comparably effective.
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Stylemans, Eric. "Etude d'un système de contre-mesure électroacoustique anti sous-marin destiné à la protection des navires." Valenciennes, 1997. http://www.theses.fr/1997VALE0007.
Повний текст джерелаАнотація:
Pour perturber les traitements du sous-marin pendant la phase de filoguidage d'une torpille et permettre au bâtiment de surface la mise en place d'une tactique efficace de réaction, un nouveau type de contre-mesure dédiée au leurrage-brouillage spécifique des senseurs du lanceur, utilisée en complément des contre-mesures anti torpilles, est indispensable. La bande d'écoute des sous-marins et des bâtiments de surface étant en partie commune, la conception d'un leurre brouilleur dans cette bande pose un problème opérationnel car toute action visant le lanceur va également perturber le porteur dans sa détection de la menace torpille. Deux nouveaux concepts de contre-mesures ont été étudiés dans ce but: * utiliser un leurre-bouilleur omnidirectionnel déployé par une roquette depuis le bâtiment de surface dans la direction estimée d'approche de la torpille * utiliser une contre-mesure a rejection contrainte à la position du porteur larguée par-dessus bord ou détachée du porteur dans le cas où elle est remorquée.
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Alexandre, Armando Emanuel Mocho fernandes e. "Wave energy converter strings for electricity generation and coastal protection." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/wave-energy-converter-strings-for-electricity-generation-and-coastal-protection(c7d53691-22f6-4ea8-a7ec-c9850218a1d5).html.
Повний текст джерелаАнотація:
Generation of electricity from ocean waves has seen increasing research and commercial interest in recent years. The development of projects of several hundred megawatts rated capacity is now being considered. There is a clear need for improved understanding of the environmental impact of large-scale wave energy extraction, particularly in nearshore regions where sediment transport and cliff erosion may be affected. This thesis investigates the change in nearshore wave conditions and sediment transport due to energy extraction by long strings of wave energy devices. The influence of wave energy converter (WEC) arrays has been studied using transmission coefficients implemented within a spectral wave model. It is shown that the breaking wave height nearshore is larger (5%) if transmission is defined as frequency dependent. This is due to the energy dissipation processes associated with different wave frequencies. Linear wave theory is employed to determine frequency dependent transmission and reflection coefficients across a line of wave energy devices based onthe amplitude of scattered and radiated waves. This approach is compared with experimental measurements of the wave field in the vicinity of an array of five heaving floats. The transmitted wave amplitude is predicted with reasonable accuracy but additional numerical damping is required to predict the measured float response amplitude. This comparison indicates that linear analysis is an acceptable approach for predicting float response and wave field in the vicinity of the array for a certain range of conditions. Linear wave analysis is subsequently applied to investigate the variation of transmission coefficients with distance inshore of a long array of heaving WECs undergoing free response and with damping specified to optimise power extraction. A method is presented for identifying representative transmission and reflection coefficients such that change in wave energy is equal to energy extraction by the devices. These coefficients are employed to quantify the change in nearshore conditions due to deployment of a long line of wave devices at a site near the East Anglian coastline. Wave conditions are modelled at 12 points along the shoreline over a 140 year period and significant wave height reductions up to 30% were obtained. Importantly, changes in nearshorewave direction are also observed. Analysis using the sediment transport model SCAPE (Soft Cliff and Platform Erosion model) indicates that the introduction of the array reduces both the sediment transport rate and cliff recession rate by an average of 50%.
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Uddin, Salman. "A novel approach to detect CT saturation using standalone CT measurements." Thesis, KTH, Elkraftteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214076.
Повний текст джерелаАнотація:
The requirement for reliability and security in power system is increasing every passingday with the increase in complexity of the power system. To ensure highest level ofreliability, protection relays have to receive correct measurements. One of the most importantmeasurement that is needed by a relay as an input is current. However, currentmeasurements received from current transformer (CT) can become inaccurate due to aphenomenon called CT saturation. This Master's thesis objective is to build a novel algorithmfor the protection relays to detect CT saturation. The algorithm should be basedon a stand-alone method that is able to detect CT saturation within 1-2 ms for a samplingfrequency of 4 kHz.This project comprises a study of the background about CTs and CT saturation. Therelated work done to detect CT saturation is also studied. Later, major existing methodsused in the industry to deal with CT saturation are investigated in detail and modelledin Simulink. A novel method is proposed to exclusively detect CT saturation, keeping inmind the strict requirements, set in the beginning of the project. The proposed methodis implemented in Simulink and HiDraw(in-house software in ABB to create C code forprotection functions). Lastly, the proposed method and the existing methods are testedin Simulink for more than 1300 test cases based on dierent power system conditions,IEC-60255-187-1 and real current recordings from relays.The results of the tests showed that the proposed method successfully detect CT saturationand was better than the existing methods in terms of speed and accuracy. It was concludedthat the proposed method successfully detects CT saturation and hence, can be used withany protection function in a relay where there is a need to detect CT saturation.Kraven pa tillforlitlighet och sakerhet i kraftsystem okar varje dag i samband med allthogre komplexitet i kraftsystemet. For att uppna den hogsta nivan av tillforlitlighetbehover relaskydden ta emot korrekta matvarden fran kraftsystemet. Ett av de mest viktigamatvardena som behovs for ett relaskydd ar strom. Emellertid, kan matvarden franen stromtransformator bli felaktiga pagrund av ett fenomen som kallas stromtransformatormattning. Malet for detta examensarbete ar att skapa en ny algoritm for relaskydd somdetekterar stromtransformatormattning. Algoritmen ska baseras pa en fristaende metodsom klarar av att detektera stromtransformatormattning inom 1-2 ms for en samplingsfrekvenspa 4 kHz.Detta projekt omfattar, forutom en studie av hur stromtransformatormattning kan detekteras,aven en bakgrundsstudie om stromtransformatorer och stromtransformatormattning.Viktigare existerande metoder, som anvands i industrin for att detektera stromtransformatormattning, undersoks i detalj och modelleras i Simulink. En ny metod foreslas foratt exklusivt detektera stromtransformatormattning med hansyn till de strikta krav somfaststalldes i borjan av projektet. Den foreslagna metoden ar implementerad i Simulinkoch i HiDraw (en intern ABB mjukvara for att skapa C-kod for skyddsfunktioner). Slutligenar den nya foreslagna metoden och de existerande metoderna testade i Simulinkmed er an 1300 testfall baserade paolika forhallanden i kraftsystemet, IEC-60255-187-1standarden och med verkliga inspelningar av strom gjorda av relaskydd i drift.Resultatet av testerna visar att den nya foreslagna metoden framgangsrikt detekterarstromtransformatormattning och gor det battre an existerande metoder med avseende pasnabbhet och noggrannhet. Det konstaterades att den nya foreslagna metoden framgangsriktdetekterar stromtransformatormattning och darfor kan anvandas for vilken relaskyddsfunktionsom helst i ett relaskydd dar behovet av att detektera stromtransformatormattningnns.
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Tsutsumi, Takuya. "Field Measurement and Analysis of Next-Generation Optical Access Network with Optical Amplifiers." Kyoto University, 2018. http://hdl.handle.net/2433/232417.
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Thomas, Michael Kyle. "Implementation of the Security-Dependability Adaptive Voting Scheme." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/32542.
Повний текст джерелаАнотація:
As the world moves further into the 21st century, the electricity demand worldwide continues to rapidly grow. The power systems that supply this growing demand continue to be pushed closer to their limits. When those limits are exceeded, system blackouts occur that have massive societal and economical impact. Power system protection relays make up a piece of these limits and can be important factors in preventing or causing a system blackout. The purpose of this thesis is to present a working implementation of an adaptive protection scheme known as the adaptive voting scheme, used to alter the security/dependability balance of protection schemes. It is argued that as power system conditions change, the ability of protection relays to adjust the security/dependability balance based on those conditions can allow relays to play a part in preventing power system catastrophes.
It is shown that the adaptive voting scheme can be implemented on existing protection technology given Wide Area Measurements (WAMs) provided by Phasor Measurement Units (PMUs). The proposed implementation characteristics allow numerous existing protection practices to be used without changing the basic operation of the practices.Master of Science
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Papier, Mark Elliot. "Real-time measurement of on-road fine particulate matter in Atlanta." Thesis, Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22544.
Повний текст джерелаАнотація:
Particulate matter is increasingly linked to health effects not only for what was previously thought to be just a respiratory problem, but also for the cardiovascular system. Literature not only supports that high particulate matter over long periods of time is correlated to morbidity and mortality due to both cardiovascular and respiratory means, but that high levels of particulate matter, even in short bursts of high concentrations, may be the triggering mechanism for the onset of such problems. Due to automobiles being a prime source of particulate matter, roadway concentrations are often higher than those measured at off-road measurement sites run by various parts of the United States Government. Furthermore, the government run sites are averaged over timescales at a minimum of an hour and at a maximum of a running three-day twenty-four hour length. These are both so long that mesoscale information about the particulate matter, such as short duration high intensity bursts, would be completely removed from the dataset. This study utilizes a real-time portable instrumentation package, which can effectively measure particulate matter concentrations on the roadways of metro Atlanta. Measurements are taken both inside the cabin of a vehicle, which does have an in-cabin filtration system, and on a bicycle ridden along the streets without any form of filtration. These instruments, specifically calibrated handheld particle counters, did indeed find some spikes of particulates above the government s one-hour averages inside the cabin of a vehicle. Arguably more importantly, while riding a bicycle these handheld particle counters also found spikes of particulates approaching six times the amount monitored by the government sites, and several roadway averages that were higher than the off-road averages for the same time.
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Younis, Ahmed. "Protection of Aluminum Alloy (AA7075) from Corrosion by Sol-Gel Technique." Doctoral thesis, Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-83230.
Повний текст джерелаАнотація:
Die vorliegende Arbeit beschäftigt sich mit der Entwicklung von Sol-Gel-Beschichtungen durch Optimierung der Ausgangszusammensetzung und der Applikations-Parameter für den Korrosionsschutz der Aluminium-Legierung AA7075. Verschiedene Arten von Silanen, z. B. Tetraethoxysilan (TEOS), Phenyltriethoxysilan (PTES) und Phenyltrimethoxysilan (PTMS) sind verglichen worden: Der Sol-Gel-Film aus PTMS präpariert, weist dabei die höchste Hydrophobizität auf, was sich insbesondere in den Barriere-Eigenschaften dieser Verbindung zeigte. Die Wirkung von Essigsäure als Katalysator in Sol-Gel-Prozessen wurden untersucht, um die optimale Katalysatorkonzentration für den Korrosionsschutz der beschichteten Proben zu ermitteln. Die Korrosionsbeständigkeit der beschichteten Proben sinkt bei höheren Konzentrationen des sauren Katalysators durch die Auflösung des Aluminiumoxids an der Substratoberfläche. Allerdings führten zu niedrige Konzentrationen des Katalysators zur Verlangsamung der Hydrolysereaktionen der Silane und es bildete sich poröse Sol-Gel-Schichten. Die Wärmebehandlung der beschichteten Aluminium-Proben ist für die Vernetzung des Films erforderlich. Eine Wärmebehandlung bei 300 ˚C für 2,5 Stunden ergab dabei den besten Korrosionsschutz. Höhere Temperaturen führten zu einer Verschlechterung der Eigenschaften der Filme, was mit der Zerstörung des organischen Teil des Films erklärt werden kann. Darüber hinaus verursachen zu niedrige Temperaturen einen geringeren Korrosionsschutz der beschichteten Aluminium-Proben. Vermutlich ist die geringe Vernetzung des Sol-Gel-Films bei Temperaturen was für als 300 ˚C verantwortlich. Die beschichteten Aluminium-Proben wuden mittels Raster-Elektronenmikroskopie (SEM), Energiedispersive Röntgenspektroskopie (EDX), Röntgen-Photoelektronenspektroskopie (XPS) und elektrochemischen Techniken charakterisiertThe present work pertains to the development of sol-gel coatings by optimizing the composition and the application parameters for corrosion protection of aluminum alloy AA7075. Different kinds of silanes e.g. tetraethoxysilane (TEOS), phenyltriethoxysilane (PTES) and phenyltrimethoxysilane (PTMS) have been compared: the sol-gel film prepared from PTMS shows highest hydrophobicity manifested by the best barrier property of this compound. The effect of acetic acid as a catalyst on the chemistry of the sol is investigated in order to estimate the best catalyst concentration for better corrosion protection of the coated samples. The corrosion resistance of the coated samples is found to be decreasing at higher concentrations of the catalyst due to the dissolution of the aluminum oxide at the substrate surface in the acid sol. However, lower concentrations of the catalyst lead to low hydrolysis reactions of the silanes and non-dense sol-gel films have been formed. The heat treatment of the coated aluminum samples is required for cross-linking of the film. The heat treatment at 300 ˚C for 2.5 hours exhibits the best corrosion protection. Higher treatment-temperatures lead to degradation of the properties of the film which can be described in terms of destroying the organic part of the film. Moreover, low treatment-temperatures cause low corrosion protection of the coated aluminum samples which is presumably attributed to the low cross-linking of the sol-gel film at temperatures less than 300 ˚C. The coated aluminum samples are characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques
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Velez-Cedeno, Francisco Gerardo. "Multiple Swing Out-of-Step Relaying." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/40394.
Повний текст джерелаАнотація:
The reduced stability margin, at which power systems are being operated these days, has encouraged the power industry to come up with new ideas to guarantee a continuous and reliable operation of the bulk interconnected system. The development of the synchronized Phasor Measurement technology, and its deployment in several locations in the network, has introduced a promising means to protect power systems from undesired conditions.
This research effort describes a methodology to handle transient stability in power systems using Wide Area Measurements. A correct identification of transiently stable and unstable power oscillations can be achieved with the use of the Out-of-Step protection technique presented in this document. The development of this idea is explained through the analysis of small power system models, and tested in three different operating conditions of the state of California.
The main contribution of this research work, to the Out-of-Step relaying theory, is the identification of multiple unstable swings after a given disturbance. In other words, an Out-of-Step protection scheme that handles a network that behaves as a multi-machine system is presented.Ph. D.
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Wiid, P. Gideon. "Lightning protection and radio frequency interference mitigation for the Karoo Array Telescope." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4009.
Повний текст джерелаАнотація:
Thesis (PhD (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: South Africa and Australia are now the two remaining countries bidding for the Square Kilometre Array (SKA), the biggest and most sensitive project ever undertaken in radio astronomy. The South African SKA is demonstrating its technology capabilities through the Karoo Array Telescope (KAT or MeerKAT). The development of KAT is taking place in stages to optimise design and minimise risks at each stage. An array of seven 12 m antennas will be complete by the end of 2009, called KAT-7. The following phase will see the construction of MeerKAT, which will lead to eighty arrayed dishes. Lightning and RFI studies for KAT-7 are the focus of this dissertation. Due to the extent and complexity of the South African demonstrator project, these studies have largely been conducted on a single structure. Parameters for the dish antenna and pedestal design changed throughout their development. To be effective, the doctoral research had to track these changes appropriately. A Method of Moments frequency domain computational electromagnetic code, FEKO, is used throughout the study. The consequences of direct and indirect lightning strikes are examined for the KAT-7 structure. Important FEKO model verification is achieved through measurement of physical scale models in an anechoic chamber. The microwave simulation code, CST, gives direct comparison of FEKO results by using a finite volume time domain method of calculation. Using frequency domain analysis on these models, the lightning down conductor design over the dish antenna bearings is optimised with cost-effectiveness as one driving parameter. RFI coupling levels for different designs are compared to each other to identify areas requiring RFI mitigation. Analysis of resonances enables evaluation of the mitigation at frequencies sensitive to radio astronomy. A Sommerfeld integral ground plane is used together with the computational model to investigate the use of the concrete foundation steel reinforcing as part of the lightning earthing electrode system. Different interconnections of the steel reinforcing elements are critically evaluated. The KAT-7 design incorporated clear lightning protection and RFI mitigation policies derived from recommendations contained within this dissertation.
AFRIKAANSE OPSOMMING: Suid-Afrika en Australie is nou die oorblywende twee lande wat bie vir die Vierkante Kilometer Reeks (SKA), die grootste en mees sensitiewe projek nog ooit in radio astronomie onderneem. Die Suid Afrikaanse SKA demonstreer sy tegnologiese bekwaamheid met die Karoo Reeks Teleskoop (KAT of MeerKAT). Die ontwikkeling van KAT vind plaas in fases om die ontwerp te optimaliseer en risikos te minimaliseer met elke fase. ’n Reeks van sewe 12 m antennas, genaamd KAT-7, sal teen die einde van 2009 klaar wees. Die volgende fase behels die konstruksie van MeerKAT, wat sal lei tot ’n tagtig-skottel reeks. Die fokus van hierdie proefskrif hanteer weerlig en radiofrekwensie steurings (RFS) vir KAT-7. As gevolg van die omvang en kompleksiteit van die Suid-Afrikaanse demonstreerder projek, is die studies hoofsaaklik op een struktuur gedoen. Parameters vir die antenna-skottel en -voetstuk ontwerp het met hul ontwikkeling deurgaans verander. Om effektief te wees, moes die doktorale navorsing hierdie veranderinge toepaslik volg. ’n Metode-van-Momente frekwensiedomein rekenaar elektromagnetiese kode, FEKO, is deurgaans met die studie gebruik. Die gevolge van direkte en indirekte weerligslae vir die KAT-7 struktuur is ondersoek. Belangrike FEKO model bevestiging is bereik met metings van skaalmodelle in ’n anego¨ıse kamer. Die mikrogolf-simulasie kode, CST, gee ’n direkte vergelyking met die FEKO resultate deur ’n eindige-volume-tyd-domein metode van berekening te gebruik. Met behulp van frekwensiedomein analise van hierdie modelle, is die weerligafleierontwerp oor die antenna-skottel laers ge-optimaliseer, met koste-effektiwiteit as een van die drywingsparameters. RFS koppelingsvlakke vir onderskeie ontwerpe is teen mekaar opgeweeg om areas te identifiseer wat RFS tempering benodig. Analise van resonansies stel die evaluering van die tempering in staat teen frekwensies wat sensitief is vir radio astronomie. ’n Sommerfeld integrale grondvlak word saam met die rekenaarmodel gebruik om die insluiting van die beton se staalversterking as deel van die aardingselektrodestelsel te ondersoek. Verskillende bindmetodes van die onderlinge staalversterkingselemente word krities ge¨evalueer. Die KAT-7 ontwerp inkorporeer duidelike weerligbeveiligings- en RFS temperingstrategie ¨e, komende van aanbevelings in hierdie proefskrif omskryf
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McKillop, Jordan M. "Reducing the activation of the IRIS reactor building using the SCALE/MAVRIC methodology." Thesis, Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/37209.
Повний текст джерелаАнотація:
The main objective of this research is: (1) to develop a model and perform numerical simulations to evaluate the radiation field and the resulting dose to personnel and activation of materials and structures throughout the IRIS nuclear power plant, and (2) to confirm that the doses are below the regulatory limit, and assess the possibility to reduce the activation of the concrete walls around the reactor vessel to below the free release limit.
IRIS is a new integral pressurized water reactor (PWR) developed by an international team led by Westinghouse with an electrical generation capacity of 335 MWe and passive safety systems. Its design differs from larger loop PWRs in that a single building houses the containment as well as all the associated equipment including the control room that must be staffed continuously. The resulting small footprint has positive safety and economic implications, and the integral layout provides additional shielding and thus the opportunity to significantly reduce the activation, but it also leads to significantly more challenging simulations.
The difficulty in modeling the entire building is the fact that the source is attenuated over 10 orders of magnitude before ever reaching the accessible areas. For an analog Monte Carlo simulation with no acceleration (variance reduction), it would take many processor-years of computation to generate results that are statistically meaningful. Instead, to generate results for this thesis, the Standardized Computer Analyses for Licensing Evaluation (SCALE) with the package Monaco with Automated Variance Reduction using Importance Calculations (MAVRIC) will be used. This package is a hybrid methodology code where the forward and adjoint deterministic calculations provide variance reduction parameters for the Monte Carlo portion to significantly reduce the computational time.
Thus, the first task will be to develop an efficient SCALE/MAVRIC model of the IRIS building. The second task will be to evaluate the dose rate and activation of materials, specifically focusing on activation of concrete walls around the reactor vessel. Finally, results and recommendations will be presented.
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Henriquez, Gonzalez Magaly. "Etude d’un traitement multifonctionnel vert pour la protection contre la corrosion de l’acier au carbone API 5L-X65 en milieu CO2." Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0030/document.
Повний текст джерелаАнотація:
L’objectif de ce travail de thèse a été d’évaluer les propriétés inhibitrices de corrosion d’un traitement multifonctionnel utilisé dans l’industrie pétrolière. Dans la première partie de la thèse, l’influence des conditions hydrodynamiques, du temps d’immersion et de la température sur les processus de corrosion de l’acier API 5L-X65 en milieu CO2 en l’absence d’inhibiteur a été étudiée par des mesures électrochimiques (courbes de polarisation, courbes de Levich et spectroscopie d’impédance électrochimique) avec une électrode à disque tournant. A partir de ces essais, la vitesse de corrosion a été calculée pour les différentes conditions expérimentales. L’analyse couplée des résultats électrochimiques et des analyses de surface suggèrent la formation d’une couche de produits de corrosion, principalement de carbonate de fer qui recouvre la surface du métal et conduit à la diminution de la vitesse de corrosion quand le temps d’immersion, la vitesse de rotation et la température augmentent. La deuxième partie de la thèse a été consacrée à l’évaluation d’un traitement multifonctionnel contre la corrosion. Ce traitement est composé principalement de produits extraits de l’Aloe Vera (gel de l’Aloe Vera et « acibar »). Ces produits ont été choisis car ils empêchent la formation simultanée d’hydrates et de carbonate de calcium. Ces composés « verts », ainsi que la dodécylamine, qui est un inhibiteur de corrosion commercial, ont été testés à l’aide des mesures électrochimiques et par perte de masse afin de comparer leur efficacité et d’évaluer un possible effet de synergie lorsqu’ils sont utilisés en mélange. Les produits testés séparément ont un pouvoir protecteur comparable et il n’a pas été mis en évidence d’effet de synergie. En revanche, il a été montré que les composés sont compatibles entre eux. Ceci constitue un point très important pour l’utilisation de ces traitements qui permettent d’augmenter la fiabilité et la rentabilité pour la production du pétrole et du gazThe objective of this work was to evaluate the corrosion inhibitive properties of a multifunctional treatment used in the petroleum industry. In the first part of the thesis, the influence of hydrodynamic conditions, immersion time and temperature on the corrosion process of API 5L-X65 steel in CO2 medium in absence of inhibitor was studied by electrochemical measurements (polarization curves, Levich curves and electrochemical impedance spectroscopy) with a rotating disk electrode. From these tests, the corrosion rate was calculated for different experimental conditions. The analysis of the electrochemical results and surface analyses suggest the formation of a layer of corrosion products, mainly iron carbonate which covers the metal surface and leads to the decrease of the corrosion rate when the immersion time, the rotation speed and temperature increase. The second part of this work was devoted to the evaluation of a multifunctional treatment against corrosion. The treatment is mainly composed Aloe Vera extracts (Aloe Vera gel and "acibar”). These products were chosen because they prevent the simultaneous formation of hydrates and calcium carbonate. These "green" compounds and dodecylamine, which is a commercial corrosion inhibitor, were tested using electrochemical measurements and by mass loss in order to compare their efficiency and to evaluate a possible synergistic effect when they are used as a mixture. The products tested separately have a similar efficiency and did not reveal any synergistic effect. However, it was shown that the compounds are compatible. This is an important point for the use of these treatments which can increase the reliability and profitability for the production of oil and gas
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Menezes, Alex Vilarindo. "A proteção de retaguarda para linhas de transmissão aplicando medição fasorial sincronizada." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-11102012-155353/.
Повний текст джерелаАнотація:
O presente trabalho tem por objetivo o desenvolvimento de uma metodologia para a proteção de retaguarda de um Sistema Elétrico de Potência (SEP) de grande área, através de um Sistema de Medição Fasorial Sincronizado (SMFS). A metodologia é baseada no contínuo monitoramento e na proteção de um SEP de grande área voltada para linhas de transmissão. Pelo algoritmo de proteção de retaguarda implementado, fundamentado na filosofia de proteção diferencial que se baseia na detecção da inversão do fluxo de potência, detecta-se a linha de transmissão faltosa mediante os dados de tensão e corrente remotamente adquiridos pelo SMFS. As simulações sobre o SEP compreenderam todas as possibilidades de curtos-circuitos monofásicos, bifásicos e trifásicos, sem e com o envolvimento da terra, variando-se o ângulo de incidência e resistência da falta dentro de uma faixa de valores encontrada em situações reais. Os resultados encontrados na pesquisa mostram a eficiência da metodologia proposta, alcançando as prescrições primárias de um sistema de proteção (velocidade, confiabilidade, seletividade e sensibilidade). Neste contexto, concluiu-se que é factível a aplicação da metodologia proposta na proteção de retaguarda de um SEP caracterizado por uma grande área de cobertura, vindo a atender aos propósitos de um sistema de proteção digital, desde que esteja disponível uma confiável e veloz infraestrutura de comunicação para o tráfego dos dados necessários.The present work aims to develop a methodology for large area Electric Power System (EPS) backup protection, through a Synchronized Phasor Measurement System (SPMS). The methodology is based on continuous monitoring and on the large area EPS protection focused on transmission lines. Through backup protection algorithm implemented, grounded on the differential protection philosophy, which is based on power flow inversion detection, detects the faulty transmission line through the remotely acquired voltage and current data by SPMS. The simulations in SEP discussed all the possibilities of single phase, two phase and three phase short-circuits, with and without the involvement of the ground, varying the fault incidence angle and resistance within a range of values commonly presented in real situation. The results found in this research show the efficiency of the proposed methodology, achieving the protection system primary requirements (speed, reliability, selectivity and sensitivity). In this context, it is concluded that it is feasible the proposed methodology application on the EPS backup protection characterized by a large coverage area, fulfilling the purposes of a digital protection system, since be available a reliable and fast communication infrastructure for the needed data traffic.
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Oliveira, Aurélien. "Conception et développement de capteurs et vêtements intelligents pour le suivi et la protection des pompiers : mesures thermiques non-invasives ambulatoires." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00677778.
Повний текст джерелаАнотація:
Les secouristes, par la nature et le cadre de leurs missions, interviennent en environnement à risque et mettent parfois leur santé en danger. Afin de minimiser ce risque, de nouveaux Equipements de Protection Individuelle (veste, tee-shirt et bottes) ont été conçus par un consortium européen de 23 partenaires réunis autour du programme de recherche ProeTEX. Ces travaux de thèse s'inscrivent dans le cadre de ce projet et ont pour objectif de développer un système de monitoring ambulatoire des paramètres thermiques du pompier qui sera intégré aux vêtements intelligents destinés aux secouristes. L'intérêt de cette intégration est le prépositionnement des capteurs afin de réduire le temps de préparation du secouriste. La surveillance s'opère à deux niveaux : l'interface Homme-environnement et le corps. Afin d'évaluer le risque thermique encouru, les paramètres faisant l'objet d'un suivi sont : la température interne, mesurée depuis le tee-shirt, et la température externe et le flux thermique, mesurés dans la veste. Ces paramètres permettent d'apprécier la contrainte thermique imposée par l'environnement et l'état de santé du pompier. Deux méthodes de mesure des paramètres thermiques dans la veste ont été développées. Le projet a abouti au développement de prototypes fonctionnels dont les performances ont été attestées en centre de validation. Des tests ont été conduits en laboratoire et en conditions extrêmes sur le terrain à la Brigade de Sapeurs-Pompier de Paris et au " International Firefighting, Survival and Rescue at Sea Training Center " de Pavie, Italie, pour démontrer la fonctionnalité des EPI en conditions réelles.