Дисертації з теми "Electric monitoring"
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1
Hendricks, Carl F. B. "Performance monitoring of electric mining shovels." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74276.
Повний текст джерелаАнотація:
A P&H 2800XP electric mining shovel working in a Western Canadian surface coal mine was instrumented with microprocessor-based monitoring equipment, and its performance monitored as it excavated a series of test blasts. Hoist and crowd motor armature voltages and currents, dipper trajectories, cycle times and load weights were recorded. A diggability index has been established based on the responses of the hoist motor. Values of the diggability index correlated well with digging conditions as observed during monitoring and with muckpile fragmentation size distributions as determined by a photographic survey. This correlation establishes the ability of an instrumented shovel to diagnose the efficiency of ground preparation practices (blasting) by identifying variations in muckpile diggability. The data on dipper trajectory has demonstrated that variations in digging practices do exist amongst an experienced group of shovel operators, and that variation in trajectory significantly influences values of the recorded motor performance parameters. An approach is described to account for variations in digging practice on assessments of diggability. An allied investigation into the ability of time studies to define diggability, revealed dig cycle times to be operator dependant, and unrelated to levels of digging effort.
2
Ramsey, Jack S. "Shipboard applications of non-intrusive load monitoring." Thesis, Monterey, California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1475.
Повний текст джерела
3
Zumr, Zdenek. "Last Mile Asset Monitoring: Low Cost Rapid Deployment Asset Monitoring." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1967.
Повний текст джерелаАнотація:
Installation and utilization of residential distribution transformers has not changed substantially over a long period of time. Utilities typically size their transformers based on a formula that takes into account broadly what types and how many dwellings will be connected.
Most new residential dwellings feature 200 Amp service per household with an anticipated energy demand of under 20,000 kWh per year. Average electrical energy consumption varies from state to state but averages to 11,280 kWh per year. Energy demand is expected to fall into a typical residential load curve that shows increased demand early in the morning, then decreasing during the day and another peak early to late evening. Distribution transformers are sized at the limit of the combined evening peak with the assumption that the transformer has enough thermal mass to absorb short overloads that may occur when concurrent loading situations among multiple dwellings arise. The assumption that concurrent loading is of short duration and the transformer can cool off during the night time has been validated over the years and has become standard practice. This has worked well when dwelling loads follow an averaging scheme and low level of coincidence.
With the arrival of electric vehicles (EV's) this assumption has to be reevaluated. The acquisition of an electric vehicle in a household can drive up energy demand by over 4000 kWh per year. Potentially problematic is the increased capacity of battery packs and the resulting proliferation of Level 2 chargers. The additional load of a single Level 2 charger concurring with the combined evening peak load will push even conservatively sized distribution transformers over their nameplate rating for a substantial amount of time. Additionally, unlike common household appliances of similar power requirements such as ovens or water heaters, a Level 2 battery charger will run at peak power consumption for several hours, and the current drawn by the EVs has very high levels of harmonic distortion. The excessive loading and harmonic profile can potentially result in damaging heat build-up resulting in asset degradation.
In this thesis I present a device and method that monitors pole mounted distribution transformers for overheating, collect and wirelessly upload data and initiate commands to chargers to change output levels from Level 2 to Level 1 or shut down EV charging altogether until the transformer returns into safe operational range.
4
Gomes, César Emanuel Brandão. "Fine grained monitoring of electric energy consumption." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/10937.
Повний текст джерелаАнотація:
Mestrado em Engenharia Electrónica e TelecomunicaçõesHoje em dia assistimos a uma grande pressão e esforço no sentido de estimular a conservação de energia, seja devido a limitações económicas, preocupações ambientais, ou normas regulatórias. No topo do consumo de energia está a energia sob a forma de electricidade Para se conseguir incentivar a utilização eficiente da energia é necessário fornecer consciencialização energética. Se os consumidores de elecricidade tiverem acesso a informação detalhada sobre como, quando e que aparelhos estão a consumir energia, estes poderão tomar boas e bem suportadas decisões e anuir mudar os seus hábitos de modo a reduzir o consumo de energia, e por fim, gastar menos dinheiro. O projecto aqui apresentado desenvolve as bases para um aparelho que fornece informação detalhada sobre o consumo de energia eléctrica para uma casa. A informação a ser fornecida deverá ser separada individualmente para virtualmente cada aparelho singular presente. A técnica escolhida para desenvolver o aparelho foi Monitorização Não Intrusiva de Cargas de Aparelhos. A partir de um único ponto de medida o sistema deverá identificar as cargas individuais na casa, o que faz com que o hardware tenda a ser simples e minimal, recaindo a complexidade para o software. O sistema desenvolvido deverá ser de baixo custo e de fácil instalação. O sistema que foi desenvolvido foi capaz de identificar individualmente e com grande sucesso os aparelhos presentes num ambiente controlado. Ao contrário de outros sistemas deste tipo, o sistema apresentado nesta dissertação é capaz de distinguir cargas eletricamente idênticas, através do uso da técnica de Medição Indirecta de Potência implementada através de uma Rede de Sensores Sem Fios.
Nowadays we witness a great pressure and effort in order to stimulate energy conservation, either due to economic constraints, environmental concerns, or regulatory pressures. At the top of the energy consumption is the consumption of energy in the form of electricity. The first step to improve energy utilization efficiency is energy awareness. So if there is some manner to provide the average person information about how he is consuming electricity, he may take it by its own interest, and In fact, if electricity consumers have access to detailed information about how, when and by which devices energy is consumed, they can make good and well supported decisions on how they can change their habits to spend less energy and ultimately spend less money. The project hereby presented, develops the basis for a device that provides detailed information on electrical energy expenditure for a home. The information to be provided aims to be disambiguated for virtually every individual appliance present. The chosen technique to develop such a device was Non-Intrusive Appliance Load Monitoring. The system identifies individual loads from a single measurement point. That makes that the hardware tends to be simple and minimal, passing the complexity to the software. The system aims to be very low cost and easy to deploy. The system developed was able to identify with great success individual appliances in the total load on a controlled environment. Unlike other systems of this type, the system presented in this dissertation has the ability of disambiguating electrically identical loads, by the use of the technique of Indirect Power Sensing deployed with a Wireless Sensor Network
5
Kryukova, N. V., Evgen Viktorovych Goncharov, and I. V. Polyakov. "Modern monitoring systems of electric power lines." Thesis, NTU "KhPI", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/38909.
Повний текст джерела
6
Jessett, Andrew. "Tools for performance monitoring of electric rope shovels /." [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16946.pdf.
Повний текст джерела
7
Sinclair, Paul Grant. "An adaptive battery monitoring system for an electric vehicle." Thesis, University of Canterbury. Department of Electrical Engineering, 1998. http://hdl.handle.net/10092/2353.
Повний текст джерелаАнотація:
In electric vehicles it is important to know the state of charge of the batteries in order to
prevent vehicle strandings and to ensure that the full range of the vehicle is exploited. It
is also useful to know state of health information about the batteries in the battery bank,
This information can be used to predict when the batteries need replacing and can also
identify batteries that are not performing optimally within the battery bank.
This thesis describes a battery monitoring system that is able to calculate the state of
charge and state of health of niultiple batteries in a battery bank, It has been designed
specifically to monitor lead-acid batteries in an electric car environment using
noninvasive measurement techniques. The monitor incorporates an adaptive monitoring
method, which is based on coulometric measurements when the batteries are under load
and predicted open circuit voltage measurements under no-load conditions.
The battery monitor is micro controller based and uses remote battery monitoring modules
to make the necessary battery measurements. Information is presented to the user of the
car in the form of a state of charge meter on the instrument panel, similar to a fuel gauge
in a conventionally power vehicle, and an alphanumeric LCn panel on the car's
dashboard. . Aspects of both the monitor hardware and software are considered in this
thesis.
Results obtained from bench tests of the monitor are presented which are followed by an
evaluation of the monitor's performance. Consideration is also given to possible future
improvements to the monitoring system.
8
Andersson, Jonas. "Ensure the electric power system's durability through battery monitoring." Thesis, Uppsala universitet, Elektricitetslära, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-244318.
Повний текст джерелаАнотація:
Battery monitoring is used to acquire information about battery conditions. It’s a regular technology that most of us uses on daily bases. The charge gauge in a cellphone, consisting of bars which indicate the degree of charge left in the battery is an example. Battery monitoring gives the cellphone user information about the battery. The background to the thesis work is that this technology is requested for vehicles because empty or broken batteries are one of the most common causes for involuntary stops. One way to monitor battery conditions is with a battery sensor, which is a mechanical device that measures and calculates battery conditions. This thesis’ purpose is to develop evaluation criteria and evaluation methods to assess the possibility for battery sensors to deliver competent information in order to ensure functionality of electric systems. To enable generalized evaluations of battery sensors, their delivered information are delimited to three different and defined battery conditions which are State-Of-Charge (SOC), State-Of-Function (SOF) and State-Of-Health (SOH). To be able to compare battery sensor calculations and actual battery conditions, a method to obtain the battery conditions was needed. To determine this method a literature review was performed and because of an accurate and continuous method was needed, Coulomb counting was selected. Coulomb counting is a book-keeping method which calculates the SOC accurate based on current integration. To develop criteria that evaluate battery sensors possibilities to deliver competent information, tests about how vehicles starting affect batteries as well as tests about battery sensors performance in different scenarios have been investigated. The thesis work shows that the SOC has to be limited based on the degree of charge left in a battery, SOF has to be limited to batteries potential to deliver a certain voltage for a specific constant current and for SOH it is most important to maintain a continuous countdown. The evaluation methods to evaluate battery sensors according to the criteria have been developed to test and ensure the battery sensors performance based on several test-cycles. The evaluation methods with certain conditions and test-cycles should be comparable to actual conditions for battery sensors installed on vehicles to ensure a continuous delivering of competent information. To summary the thesis work has developed and partly verified evaluation criteria and evaluation methods to evaluate battery sensors possibility to deliver competent information about the battery conditions SOC, SOF and SOH. These criteria and methods make it possible to evaluate if a battery sensor, any battery sensor calculating these battery conditions based on similar parameters, could deliver enough competent information in order to ensure functionality of electric systems.
9
Wafula, Alfred Brian. "Dynamic Monitoring of Cytotoxicity Using Electric Cell Substrate Impendence Sensing." Scholar Commons, 2006. http://scholarcommons.usf.edu/etd/3800.
Повний текст джерелаАнотація:
Electric cell-substrate impedance sensing (ECIS) pioneered by Giaever and Keese is suitable for continuous, automatic and real-time cell attachment analysis. ECIS is a novel electrical method to study, in real time, many of the activities of animal cells when grown in tissue culture. These include morphological changes, cell locomotion, and other behaviors directed by the cell's cytoskeleton. One of the most direct ECIS measurements is that of the attachment and spreading behaviors of cells. These measurements allow one to study and quantify the interaction of cultured cells with extracellular matrix (ECM) proteins and other macromolecules continuously and in real time. Traditionally, cell attachment and spreading measurements are labor intensive, requiring many manipulations of the cultures for microscopic evaluation of cell behavior. With ECIS, these same measurements can be made in an automated approach without opening the door of the incubator. The ECIS core technology is based on a technique of measuring the change in impedance of a small electrode to AC current flow. The heart of the measurement is a specialized slide that has 8 individual wells for cell culturing. The base of the device has an array of gold film electrodes that connect to the ECIS electronics to each of the 8 wells.
In our work we used ECIS to study the attachment and spread of HUVEC and 3T3 cells. The curve of HUVEC showed higher resistances than that of 3T3 cells. This was due to the fact we used gelatin to aid in attachment of HUVECs which accounted for the high resistances. 3T3 cells attached easily without help of gelatin. We also studied the cytotoxicity of HUVEC and 3T3 cells. The drugs that we used were CB, H7 and CdCl2. We found that the best drug was CB since it affected the cells even at low concentrations. H7 effects were mild while CdCl2 only worked at high concentrations. HUVEC cells make loose contact on electrodes and are easily detached by drugs. 3T3 makes firm at tachment to the electrodes and are not easily detached from the electrodes.
Electrical impedance measurements on multiple electrodes are highly attractive in this application because of the potential for direct computer control.
10
Lee, Kwangduk Douglas 1970. "Electric load information system based on non-intrusive power monitoring." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29633.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2003.Includes bibliographical references (leaves 192-200).
Obtaining high quality information economically and reliably is always a difficult objective to achieve. The electric power industry and consumers recently face many challenges, such as deregulation, autonomous power systems and power quality. The knowledge of the nature and state of the power systems will undoubtedly be the key in meeting these challenges. The Non-Intrusive Power Monitor is a novel attempt to collect such information with a minimal physical installation. Raw voltage and current are measured at a single location to yield harmonic power signals. They typically carry the fingerprints of the electric loads present in a system, and their analysis can produce such information as the operational and diagnostic status of the loads. The power signals can also be used for the system identification, parameter estimation and energy consumption optimization study. In this research, the power signals are mostly modeled as stochastic processes and various detection, estimation and pattern recognition algorithms are developed to extract desired information. A constant load status identifier is developed in this thesis which can identify the ON and OFF status of electric loads, both from their steady-state power consumptions and transient patterns. The identifier can also classify multiple load events occurring at a same time and estimate states without load events. The power consumed by a variable speed drive is also estimated using the correlations between the fundamental powers and higher harmonic powers. The harmonic signal generated by the imbalance of a rotating machine is estimated to monitor the drive, i.e. its speed and magnitude of the imbalance. The algorithms are thoroughly tested using the data collected at real buildings, and some of them are implemented on-line.
(cont.) This thesis focuses on developing mathematical models and signal processing algorithms for the customers at the end of the AC distribution system. Its results will directly benefit the developments of a ubiquitous electric meter in a deregulated market, a diagnostic or prognostic tool for mission-critical systems and an intelligent power quality monitor.
by Kwangduk Douglas Lee.
Ph.D.
11
Chan, Yau Chung John. "A novel electric power quality monitoring system for transient analysis." Thesis, City University London, 2014. http://openaccess.city.ac.uk/5911/.
Повний текст джерелаАнотація:
Electricity is vital for our daily life in modern cites. In order to ensure its reliability and supply, an electric power monitoring system is indispensable in an electric power system. Currently, most electric power monitoring systems are designed for steady-state monitoring only. They may not be able to monitor instantaneous power disturbances, such as voltage surge, happened in electric power systems. In fact, instantaneous power disturbances are frequently found in electric power systems, which result in equipment failures and cause financial losses. Therefore, a novel electric power monitoring system is proposed in this thesis. Besides traditional functions, the proposed system is capable of monitoring and analyzing instantaneous power disturbances in electric power systems. Novelties of the proposed monitoring system are in the following three major aspects. Firstly, the proposed system is capable of monitoring instantaneous power disturbances. Unlike traditional monitoring systems, the proposed system captures not only statistical power quantities (e.g. kW, kWh), but also voltage and current waveforms. Since a considerable communication network bandwidth is required to transmit electric waveforms in a remote monitoring system, a novel waveform compression algorithm is proposed to realize real-time electric power waveform monitoring on low-speed communication networks (e.g. Zigbee). Secondly, the proposed system is capable of identifying various kinds of power disturbances automatically. It relieves electrical engineers from manned disturbance identification on preserved waveforms. Unlike traditional disturbance identification algorithms, the proposed system can identify not only voltage disturbances, but also current disturbances. Hence, it can provide a better chance in identifying more problems and disturbances in electric power systems. Thirdly, a novel time-frequency analysis method is proposed to analyze preserved waveforms. The proposed method is an improvement to the well-known Discrete Wavelet Packet Transform (DWPT). DWPT has been used by researchers and engineers to analyze disturbances and harmonics in electric power systems. However, DWPT is subjected to a non-uniform leakage problem, which has been discussed intensively in many studies. In order to tackle this issue, a frequency shifting scheme is introduced in the proposed method. A prototype has been implemented to demonstrate the feasibility of the proposed electric power monitoring system. There are two major components – a prototype meter and a central monitoring system. The performance of the prototype has been evaluated by conducting experiments and field tests. The capability of the proposed system for realtime remote monitoring has been verified on Zigbee network, which is a low-power, low speed wireless communication network.
12
Zandberg, Hermanus Andries Jakobus. "Wireless transformer condition monitoring system." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/1186.
Повний текст джерелаАнотація:
The Department of Electrical Engineering in fulfilment of the
requirements for the Magister Technologiae in Electrical
Engineering at the
Cape Peninsula University of Technology
November 2013Pole mounted transformers (PMT) in rural areas present an opportunity for local utilities to do current monitoring on these systems. These transformers are exposed to abnormal amounts of stress due to the vast power demand in these areas. The aim of this study is to develop a more cost-effective condition monitoring system. Transformer current monitoring can be a dangerous practice if not done by suitably trained utility electricians. Hence this study is partly aimed at the elimination of hazardous working environments associated with manual electrical measurements. An investigation to determine a safe and cost-effective way to obtain the electrical measurements required from PMTs is undertaken. Although current measurements can be done with a current clamp-on meter, these measurements still take place at the phases of the transformer and are unsafe. The possibility of implementing wireless data gathering on current clamp-on meters is therefore investigated. This is made possible by a wireless sensor node (WSN) which gathers information and transmits it wirelessly to a WSN base station. This wireless solution is battery powered, necessitating battery replacements, therefore leading to the investigation of magnetic fields, magnetic materials and magnetic induction. A current clamp able to generate a high voltage (HV) output with minimal magnetic field strength is developed. The magnetic fields produced by the transformer’s phase cables are used to generate an alternating voltage. With the help of a microcontroller and an energy harvesting circuit, this voltage is converted and used to charge supercapacitors. The magnetic fields are also used to determine the current flow in the transformer phase cables when the device is not in energy harvesting mode. The device will then undergo comprehensive laboratory testing to determine its accuracy and durability, and is then used to do ‘real life’ current measurements, the results of which are compared against an off-the-shelf current monitoring device.
13
Schwardt, Wilhelm Heinrich. "Insulator pollution monitoring device : development, calibration and field evaluation." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50372.
Повний текст джерелаАнотація:
Thesis (MScEng)--University of Stellenbosch, 2005.ENGLISH ABSTRACT: The calibration and field evaluation of an Insulator Pollution Monitoring Relay (IPMR) were the main aims of this research programme. A repeatable artificial wetting test method was developed after several modifications were made to the steam system, test chamber and the test routine. The IPMR was successfully calibrated with insulators that were artificially polluted according to the solid layer method. Linear and polynomial relationships were determined after curve-fitting techniques were performed on the results. The calibration showed that the IPMR is capable as a device relating the maximum conductivity during artificial wetting to the ESDD, a severity classification parameter. The IPMR was successfully used in a salt fog chamber to determine if the device is capable to evaluate the severity of an instantaneous pollution event. The IPMR was successfully installed at a natural pollution test site along the Cape west coast. The conductivity measurements with natural wetting showed good correlation to flashovers experienced. A rule of thumb, developed to indicate a possible risk of flashover, was based on observations made on the relationship between humidity and surface conductivity. The measured IPMR data was successfully applied to quantify the site severity according to the conductivity measurement with natural wetting. This calculated severity value could be used in the assessment of flashover probability of high voltage insulators.
AFRIKAANSE OPSOMMING: Die hoofdoel van die tesis was die kalibrasie en veldtoetse van 'n isolatorbesoedelingsmonitor (IPMR). 'n Herhaalbare nagebootste benatting-toetsmetode is ontwikkel na veranderings aan die stoomstelsel, toetsruimte en die toetsproses. Die IPMR is suksesvol gekalibreer met isolators wat besoedel was met 'n nagebootste besoedeling volgens die "solid layer method". Liniêre sowel as kwadratiese verwantskappe is ontwikkel na krommepassings op die resultate uitgevoer was. Die kalibrasie het gewys dat die IPMR in staat is om die maksimum geleidingsvermoë wat d.m.v. nagebootste benatting verkry is, met die ESDD, 'n besoedelingsklassifikasie, kan vergelyk. Die apparaat is ook suksesvol gebruik tydens soutmistoetse om te bepaal of dit in staat is om 'n skielike besoedelingsgebeurtenis te kan meet. Na die afhandeling van laboratorium werk is die apparaat by 'n natuurlike isolator besoedeling-toetsstasie langs die Kaapse weskus geïnstalleer. Die geleidingsvermoë metings met natuurlike benatting het goeie korrelasie getoon met isolator oorvonkings. 'n Skattingsmetode wat ontwikkel is om moontlike oorvonkings te voorspel, is gebaseer op waarnemings wat gemaak is van die humiditeit sowel as die oppervlakte geleidingsvermoë. Die IPMR se geleidingsvermoë metings met natuurlike benatting is aangewend om die besoedelingsgraad van die gebied te bepaal. Die bepaalde besoedelingsgraad kan verder gebruik word om die waarskynlikheid van die oorvonking van isolators vas te stel.
14
Gomez, Poo David Fernando. "Electric Fence to PC Wireless Radio Frequency Communications Interface." The University of Waikato, 2006. http://hdl.handle.net/10289/2440.
Повний текст джерелаАнотація:
Electric fencing is commonly used on New Zealand's farms. Modern technology is used in farm management systems to solve old farming problems in a more efficient and simple way. Engineers have researched the use of the electric fence as a communication medium and new technologies based on transmission line theory are used at present to monitor and troubleshoot problems occurring in electric fences. The next stage of the development is to use wireless devices to accomplish those same tasks from remote locations. This project aims to develop a prototype that provides a wireless link between an electric fence and a personal computer in a remote location. This prototype is expected to prove concepts that lead to the future design of useful, marketable products. The project was supported by Gallagher Electronics and is implemented using their existing products where possible.
15
Liu, Guoping. "Oscillation monitoring system based on wide area phasor measurements in power systems." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Dissertations/Summer2010/g_liu_060110.pdf.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Washington State University, August 2010.Title from PDF title page (viewed on July 23, 2010). "School of Electrical Engineering and Computer Science." Includes bibliographical references (p. 76-81).
16
Nduku, Nyaniso Prudent. "Development of methods for distribution network power quality variation monitoring." Thesis, Cape Peninsula University of Technology, 2009. http://hdl.handle.net/20.500.11838/1144.
Повний текст джерелаАнотація:
Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2009The purpose of this project is to develop methods for distribution network power quality' variations monitoring. Power quality (PO) has become a significant issue for both power suppliers and customers. There have been important changes in power system regarding to power quality requirements. "Power quality" is the combination at voltage quality and current quality. The main research problem of the project is to investigate the power quality of a distribution network by selection of proper measurement, applying and developing the existing classic and modern signal conditioning methods for power disturbance's parameters extracting and monitoring. The research objectives are: To study the standard lEC 61000-4-30 requirements. to investigate the common couplings in the distribution network. To identity the points for measurement, to develop MySQL database for the data from the measurement and to develop MATLAB software tor simulation of the network To develop methods based on Fourier transforms for estimation of the parameters of the disturbances. To develop software for the methods implementation, The influence of different loads on power quality disturbances are considered in the distribution network. Points on the network and meters according to the lEC power quality standards are investigated and applied for the CPUT Bellville campus distribution network. The implementation of the power quality monitoring for the CPUT Bellville campus helps the quality of power supply to be improved and the used power to be reduced. MATLAB programs to communicate with the database and calculate the disturbances and power quality parameters are developed.
17
Chan, Ting. "Analytical methods for power monitoring and control in an underwater observatory /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/6053.
Повний текст джерела
18
Tan, Pee-Chin 1975. "A VSI-based power quality conditioner for 25kV electrified railway systems." Monash University, Dept. of Electrical and Computer Systems Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/5537.
Повний текст джерела
19
Abrahams, Leon Gary. "Computerised speed monitoring system for nylon spinning." Thesis, Peninsula Technikon, 1996. http://hdl.handle.net/20.500.11838/1123.
Повний текст джерелаАнотація:
Thesis (MTech (Electrical Engineering))--Peninsula Technikon, Cape Town,1996The Southern Nylon Spinning plant, at South African Nylon Spinners in Bellville - Cape Town - South Africa, is one of the oldest on the site and a need arose to upgrade the existing method used in speed monitoring in this particular plant. This system was unable to produce alarms on speed limits being exceeded (i.e. on under-speed or over-speed). There was no alarm logging or historical trending. Manual records on speed were either incomplete or non-existent. Thus the purpose of this study was to investigate the existing speed monitoring system and implement a suitable computerised method of speed monitoring.
20
Wafula, Alfred Brian. "Dynamic monitoring of cytotoxicity by using electric cell substrate impedance sensing." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001562.
Повний текст джерела
21
Atkins, David Wayne. "Placing monitoring devices in electric power networks modeled by block graphs." [Johnson City, Tenn. : East Tennessee State University], 2003. http://etd-submit.etsu.edu/etd/theses/available/etd-0713103-210119/unrestricted/AtkinsD080503f.pdf.
Повний текст джерелаАнотація:
Thesis (M.S.)--East Tennessee State University, 2003.Title from electronic submission form. ETSU ETD database URN: etd-0713103-210119. Includes bibliographical references. Also available via Internet at the UMI web site.
22
Begovic, Miroslav M. "Analysis, monitoring and control of voltage stability in electric power systems." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54490.
Повний текст джерелаАнотація:
The work presented in this text concentrates on three aspects of voltage stability studies: analysis and determination of suitable proximity indicators, design of an effective real-time monitoring system, and determination of appropriate emergency control techniques. A simulation model of voltage collapse was built as analytical tool on 39-bus, 10-generator power system model. Voltage collapse was modeled as a saddle-node bifurcation of the system dynamic model reached by increasing the system loading. Suitable indicators for real-time monitoring were found to be the minimum singular value of power flow Jacobian matrix and generated reactive powers. A study of possibilities for reducing the number of measurements of voltage phasors needed for voltage stability monitoring was also made. The idea of load bus coherency with respect to voltage dynamics was introduced. An algorithm was presented which determines the coherent clusters of load buses in a power system based on an arbitrary criterion function, and the analysis completed with two proposed coherency criteria. Very good agreement was obtained by simulation between the results based on accurate and approximate measurements of the state vector. An algorithm was presented for identification of critical sets of loads in a voltage unstable power system, defined as a subset of loads whose changes have the most pronounced effect on the changes of minimum singular value of load flow Jacobian or generated reactive powers. Effects of load shedding of critical loads were investigated by simulation and favorable results obtained. An investigation was also done by sensitivity analysis of proximity indicators of the effects that locations and amounts of static var compensation have on the stability margin of the system. Static compensation was found to be of limited help when voltage instabilities due to heavy system loading occur in power systems. The feasibility of implementation of the analyses and algorithms presented in this text relies on development of a feasible integrated monitoring and control hardware. The phasor measurement system which was designed at Virginia Polytechnic institute and State University represents an excellent candidate for implementation of real-time monitoring and control procedures.Ph. D.
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Oubrahim, Zakarya. "On electric grid power quality monitoring using parametric signal processing techniques." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0102/document.
Повний текст джерелаАнотація:
Cette thèse porte sur la surveillance des perturbations de la qualité de l’énergie d’un réseau électrique via des techniques paramétriques de traitement du signal. Pour élaborer nos algorithmes de traitement du signal, nous avons traité les problèmes d’estimation des différentes grandeurs du réseau électrique triphasé et de classification des perturbations de la qualité d'énergie. Pour ce qui est du problème d’estimation, nous avons développé une technique statistique basée sur le maximum de vraisemblance. La technique proposée exploite la nature multidimensionnelle des signaux électriques. Elle utilise un algorithme d’optimisation pour minimiser la fonction de vraisemblance. L’algorithme utilisé permet d’améliorer les performances d’estimation tout en étant d’une faible complexité calculatoire en comparaison aux algorithmes classiques. Une analyse plus poussée de l’estimateur proposé a été effectuée. Plus précisément, ses performances sont évaluées sous un environnement incluant entre autres la pollution harmonique et interharmonique et le bruit. Les performances sont également comparées aux exigences de la norme IEEE C37.118.2011. La problématique de classification dans les réseaux électriques triphasés a plus particulièrement concerné les perturbations que sont les creux de tension et les surtensions. La technique de classification proposée consiste globalement en deux étapes : 1) une pré-classification du signal dans l’une des 4 préclasses établis et en 2) une classification du type de perturbation à l’aide de l’estimation des composants symétriques.Les performances du classificateur proposé ont été évaluées, entre autres, pour différentes nombre de cycles, de SNR et de THD. L’estimateur et le classificateur proposés ont été validés en simulation et en utilisant les données d’un réseau électrique réel du DOE/EPRI National Database of Power System Events. Les résultats obtenus illustrent clairement l’efficacité des algorithmes proposés quand à leur utilisation comme outil de surveillance de la qualité d’énergieThis thesis deals with electric grid monitoring of power quality (PQ) disturbances using parametric signal processing techniques. The first contribution is devoted to the parametric spectral estimation approach for signal parameter extraction. The proposed approach exploits the multidimensional nature of the electrical signals.For spectral estimation, it uses an optimization algorithm to minimize the likelihood function. In particular, this algorithm allows to improve the estimation accuracy and has lower computational complexity than classical algorithms. An in-depth analysis of the proposed estimator has been performed. Specifically, the estimator performances are evaluated under noisy, harmonic, interharmonic, and off-nominal frequency environment. These performances are also compared with the requirements of the IEEE Standard C37.118.2011. The achieved results have shown that the proposed approach is an attractive choice for PQ measurement devices such as phasor measurement units (PMUs). The second contribution deals with the classification of power quality disturbances in three-phase power systems. Specifically, this approach focuses on voltage sag and swell signatures. The proposed classification approach is based on two main steps: 1) the signal pre-classification into one of 4 pre-classes and 2) the signature type classification using the estimate of the symmetrical components. The classifier performances have been evaluated for different data length, signal to noise ratio, interharmonic, and total harmonic distortion. The proposed estimator and classifier are validated using real power system data obtained from the DOE/EPRI National Database of Power System Events. The achieved simulations and experimental results clearly illustrate the effectiveness of the proposed techniques for PQ monitoring purpose
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Kunchum, Sandeep. "A network infrastructure for real-time monitoring of campus energy consumption." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/Kunchum_09007dcc80490489.pdf.
Повний текст джерелаАнотація:
Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed March 26, 2008) Includes bibliographical references (p. 83-84).
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Cash, M. Alex. "Detection of turn faults arising from insulation failure in the stator windings of AC machines." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/15460.
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Hurst, Kevin D. "Transducerless control and monitoring of induction machines by detection of magnetic saliency harmonics." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/15713.
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Kokko, V. (Voitto). "Condition monitoring of squirrel-cage motors by axial magnetic flux measurements." Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514269381.
Повний текст джерелаАнотація:
Abstract
The aim of this research work is to develop a tool for condition monitoring of squirrel-cage motors using axial magnetic flux measurements, and to design a diagnostics system for electrical motors. The basic theory of the measurements and systems was found through literature reviews and was further developed from the experimental results of this research work.
Fluxgate magnetometers and Hall effect sensors are not reliable enough for condition monitoring purposes, but measurements by flux coil sensors can reach adequate reliability. The useful frequency area of the flux coil sensor is from about 0.2 Hz to 15 kHz, an area is well applicable for condition monitoring of squirrel-cage motors. Output voltage is frequency dependent, increasing towards higher frequencies. Sufficient sensitivity is usually reached by a flux coil sensor having a diameter of about 30 cm and the number of turns of about 200. Sensitivity can be improved by increasing the diameter or number of turns of the coil. The sensor should be placed axially centred on the end of the motor, and measurements should be made with the loaded motor in steady operation. Output voltage is typically from the microvolt to millivolt level, however, installation inside the motor can increase it from tens of millivolts to some volts. The dynamic resolution requirement of measurement is about 70 dB and the highest line resolution needed for the spectrum analysis is about 3200 lines.
Time base signal can be used to study rapid disturbances of flux caused by mechanical loading or switching of the frequency converter. Various motor failures cause specific variation to the frequency distribution of flux, so spectrum analysis is well applicable for condition monitoring. Reference measurement of each motor is required because stator winding factors, installation tolerances, operating conditions and mechanical load affect leakage flux. A broken rotor bar failure can be detected from the amplitude difference between the supply frequency and its rotor bar induced sideband. A broken rotor end ring failure can be detected by the amplitude difference between the slip frequency and the supply frequency. However, it was found that the stator current spectrum is a more reliable method of detecting both these rotor failures. The supply voltage asymmetry can also be evaluated by specific sidebands of axial flux. Turn to turn failure of the stator winding was most reliably detected by sidebands around the rotor slot pass frequencies. Equations for frequency converter supplied motors are the bases for similar equations, but the supply frequency is replaced by the output current frequency of the converter.
The developed diagnostics system design for condition monitoring of ac motors includes stator current, flux coil, temperature, vibration, partial discharge, bearing current and voltage measurements. At the system diagnosis stage these measurable signals are divided to time base and frequency base signals and for each of them a fault indicator is determined. For flux coil measurements four fault indicators were found: rotor bar failure ratio, rotor end ring failure ratio, stator winding turn to turn ratio and supply voltage asymmetry operation ratio. With these failure indicators we determine failure location, state and cause. From this information a lifetime prediction of the motor is made.
The results of this work are used to analyse flux coil measurements of squirrel-cage motors. In addition the research has led to a special application to monitor electric motors using an on-line condition monitoring system for paper machines and power plants.
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Siyambalapitiya, Don Joseph Tilak. "Investigation of cage rotor variables including on-line monitoring." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237745.
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陳偉樂 and Wai-lok Chan. "Multi-function monitoring system for harmonic and transient study of power networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B31210727.
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Chan, Wai-lok. "Multi-function monitoring system for harmonic and transient study of power networks /." [Hong Kong : University of Hong Kong], 1992. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13418051.
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Lee, Seungkoo. "An architecture for a diagnostic/prognostic system with rough set feature selection and diagnostic decision fusion capabilities." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/14715.
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Schoen, Randy R. "On-line current-based condition monitoring of three-phase induction machines." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/12952.
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Jiang, Bing. "Ubiquitous monitoring of distributed infrastructures /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/6118.
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Milošević, Borka. "On voltage stability monitoring and control using multiagent systems." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/16355.
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Baldwin, Thomas L. "Real-time phasor measurements for improved monitoring and control of power system stability." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-170758/.
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Lu, Bin. "Energy Usage Evaluation and Condition Monitoring for Electric Machines using Wireless Sensor Networks." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14152.
Повний текст джерелаАнотація:
Energy usage evaluation and condition monitoring for electric machines are important in industry for overall energy savings. Traditionally these functions are realized only for large motors in wired systems formed by communication cables and various types of sensors. The unique characteristics of the wireless sensor networks (WSN) make them the ideal wireless structure for low-cost energy management in industrial plants.
This work focuses on developing nonintrusive motor-efficiency-estimation methods, which are essential in the wireless motor-energy-management systems in a WSN architecture that is capable of improving overall energy savings in U.S. industry.
This work starts with an investigation of existing motor-efficiency-evaluation methods. Based on the findings, a general approach of developing nonintrusive efficiency-estimation methods is proposed, incorporating sensorless rotor-speed detection, stator-resistance estimation, and loss estimation techniques. Following this approach, two new methods are proposed for estimating the efficiencies of in-service induction motors, using air-gap torque estimation and a modified induction motor equivalent circuit, respectively. The experimental results show that both methods achieve accurate efficiency estimates within ¡À2-3% errors under normal load conditions, using only a few cycles of input voltages and currents. The analytical results obtained from error analysis agree well with the experimental results.
Using the proposed efficiency-estimation methods, a closed-loop motor-energy-management scheme for industrial plants with a WSN architecture is proposed. Besides the energy-usage-evaluation algorithms, this scheme also incorporates various sensorless current-based motor-condition-monitoring algorithms. A uniform data interface is defined to seamlessly integrate these energy-evaluation and condition-monitoring algorithms. Prototype wireless sensor devices are designed and implemented to satisfy the specific needs of motor energy management. A WSN test bed is implemented. The applicability of the proposed scheme is validated from the experimental results using multiple motors with different physical configurations under various load conditions. To demonstrate the validity of the measured and estimated motor efficiencies in the experiments presented in this work, an in-depth error analysis on motor efficiency measurement and estimation is conducted, using maximum error estimation, worst-case error estimation, and realistic error estimation techniques. The conclusions, contributions, and recommendations are summarized at the end.
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Waag, Wladislaw [Verfasser]. "Adaptive algorithms for monitoring of lithium-ion batteries in electric vehicles / Wladislaw Waag." Aachen : Shaker, 2014. http://d-nb.info/1060622254/34.
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Sun, Xu, and 孫旭. "Development of power system monitoring by magnetic field sensing with spintronic sensors." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196015.
Повний текст джерелаАнотація:
This dissertation presents novel application of spintronic sensors in power system monitoring. Spintronic sensors including giant magnetoresistance (GMR) sensors and tunnel magnetoresistance (TMR) sensors are advanced in magnetic field sensing. In power industry, power-frequency magnetic fields are produced by electric power sources, equipment and power lines. Thus it is impossible for monitoring the power system by sensing the emanated magnetic field. In Chapter 2, a novel concept based on magnetoresistive (MR) sensors is proposed for transmission line monitoring. A proof-of-concept laboratory setup was constructed and a series of experiments were carried out for demonstration. The result shows the feasibility of using this power system monitoring method in reality.
In order to handle complicated transmission line configuration with the proposed method, an improved current monitoring technology is proposed in Chapter 3. It is realized by developing a current source reconstruction method based on stochastic optimization strategy. This concept of current monitoring by magnetic field sensing and current source reconstruction was experimentally implemented and verified in our laboratory setup. A typical model of 500 kV three-phase transmission lines was simulated to further corroborate this technology. The reconstruction results for the 500 kV transmission lines verify the feasibility and practicality of this novel current monitoring technology based on magnetic field sensing at the top of a transmission tower for monitoring overhead transmission lines.
Chapter 4 offers further improvement of the transmission-line monitoring technology. Improved technology can measure simultaneously both electrical and spatial parameters of multiple lines in real-time in a non-contact way. Two typical models of high-voltage three-phase transmission lines were simulated and the resulting magnetic fields were calculated. A source reconstruction method was developed to reconstruct the spatial and electrical parameters from the magnetic field emanated by the overhead transmission lines. The reconstruction results for the 500 kV and 220 kV transmission lines verify the feasibility and practicality of this non-contact transmission-line monitoring technology based on magnetic field sensing.
As well as the high-voltage transmission-line, the technology is applied in underground power cable operation-state monitoring and energization-status identification in Chapter 5. The magnetic field distribution of the cable was studied by using finite element method (FEM) for the power cable operating in different states, i.e. current-energized state (the cable is energized and carries load current) and voltage-energized state (the cable is energized but carries no load current). Application of this method was demonstrated on an 11 kV cable with metallic outer sheath. The results highly matched with the actual source parameters of the cable. An experimental setup was constructed and the test results were used for demonstration this method.
In order to enhance the applicability of the proposed power system monitoring technology in practice, magnetic flux concentrators (MFC) and magnetic shielding are studied and designed for MR sensors in Chapter 6.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
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Wood, Colin Hugh. "An appraisal of artifical neural networks for condition monitoring of product quality." Thesis, Glasgow Caledonian University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270521.
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Prinsloo, Nick. "Design and development of a battery cell voltage monitoring system." Thesis, Cape Peninsula University of Technology, 2011. http://hdl.handle.net/20.500.11838/1109.
Повний текст джерелаАнотація:
Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2011The purpose of this thesis was to design and develop a measurement system that would allow accurate measurement of individual cell voltages in a series cell stack. The system was initially proposed to be used in conjunction with an active cell balancer. This would allow for the efficient equalising of cells as well as provide detailed information on the cell stack and how the stack operates over time. Having a system that measures voltages accurately, with which the active cell balancer can be controlled would allow for peak cell lifetime and performance. Current battery management systems are large, complex and inefficient and a new way of battery management had to be investigated. To accurately measure individual cells in a series stack, the high common mode voltage must be negated. Different techniques that are currently used to create galvanic isolation were reviewed; circuits were designed and were simulated to find the most suitable design. The traditional methods used to create galvanic isolation did not provide adequate results. The methods were too inefficient and not accurate enough to be used. The methods that had the required accuracy were too complicated to connect in a useable system. This led to the investigation of integrated circuits created to measure voltages in large cell stacks. An integrated circuit from Linear Technology was chosen and a system was built. A system was thus designed that fulfilled the most desirable design specifications while delivering excellent results. The system allowed accurate, individual voltages to be measured in the presence of high common mode voltages. Accuracies and measurement time were well below the required system specification. Power consumption was high, but different component choice will lower power consumption to within specification. Excellent results were obtained overall with most, although not all results well below the design specifications. By including current measurements, as well as other technologies such as wireless communication, USB connectivity and a better data processor, this system will be at the forefront of current battery management technology.
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Mitchell, Gregory R. "Shipboard fluid system diagnostics using non-intrusive load monitoring." Thesis, Monterey, California. Naval Postgraduate School, 2007. http://hdl.handle.net/10945/2997.
Повний текст джерелаАнотація:
CIVINSSystems on modern naval vessels are becoming exclusively dependent on electrical power. One example of this is the replacement of distilling and evaporator plants with reverse osmosis units. As the system is in continuous operation, it is critical to have remote real-time monitoring and diagnostic capabilities. The pressure to reduce shipboard manning only adds to the difficulties associated with monitoring such systems. One diagnostic platform that is particularly well suited for use in such an environment is the non-intrusive load monitor (NILM). The primary benefit of the NILM is that it can assess the operational status of multiple electrical loads from a single set of measurements collected at a central point in a ship's power-distribution network. This reduction in sensor count makes the NILM a low cost and highly reliable system. System modeling, laboratory experiments, and field studies have all shown that the NILM can effectively detect and diagnose several critical faults in shipboard fluid systems. For instance, data collected from the reverse osmosis units for two U.S. Coast Guard Medium Endurance Cutters indicate that the NILM can detect micron filter clogging, membrane failures, and several motor-related problems. Field-tested diagnostic indicators have been developed using a combination of physical modeling and laboratory experiments.
CIVINS
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Da, Silva domingues Elizabeth. "Improved condition monitoring of composite insulators." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/improved-condition-monitoring-of-composite-insulators(d42e15fb-d9c2-4e45-94b9-3321e9d9b9f0).html.
Повний текст джерелаАнотація:
Although the cost of investment in power lines insulators is 3-5% of the total cost of the installation, the impact of their performance on reliability, failure costs, maintenance routines, etc in power systems is tens of times higher. Composite insulators were introduced 50 years ago and have been used around the world with consistently good experience. Low weight, easy handling, good performance under high pollution, low maintenance costs, and resistance to vandalism are some of their advantages. Nevertheless, acid rain, salty dust deposition, corona discharges, ozone, UV radiation, and humidity among other factors, deteriorate the quality of the polymeric housing reducing their hydrophobicity. The synergistic action of ageing factors is extremely complex and the whole degradation process may change when any one variable is slightly modified. Many studies have been carried out to increase understanding of the physicochemical processes which control the electrical and mechanical stability of polymers during in-service ageing with the objective of predicting remaining life-times. Vital areas of knowledge about polymer insulators are still incomplete and lacking; three of them are: (1) early stages of degradation in service under different environmental conditions, (2) monitoring and diagnosis techniques suitable for distribution installations and (3) steps to establish an insulators management plan based on condition and risk of failure. In this research these three topics are covered. A full review of literature about management of electrical distribution assets is included, followed by a specific plan developed for monitoring, diagnosis and ranking of insulators mainly supported by visual inspections. Diagnosis of medium voltages EPDM insulators recovered from service aged under different conditions is done using both traditional techniques and, uniquely, dielectric impedance. The relationship between surface roughness and static contact angle is also used to characterize insulators' surfaces. Early stages of degradation are studied focusing the experimental work to evaluate the electrohydrodynamic processes which occur on new samples under different conditions, giving special attention to leakage current pulse analysis, electric field enhancement, and resistance/capacitive behaviour including phase of leakage current. Results from each specific topic offer additional understanding of polymer insulators degradation providing insight to monitoring, diagnosis and management. Additionally, results open new topics in which new investigations are proposed.
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Elsmore, Chris. "Neighbourhood Watch : social resource monitoring." Thesis, Swansea University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678659.
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44
Lee, Sang-Bin. "Sensorless stator winding temperature estimation for induction machines." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/14719.
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45
Aleksandrova, Alina. "Magnetic Field Monitoring in the SNS Neutron EDM Experiment." UKnowledge, 2019. https://uknowledge.uky.edu/physastron_etds/68.
Повний текст джерелаАнотація:
It is a well known fact that the visible universe is made almost entirely of baryonic matter. Yet, this is also one of the greatest puzzles that physicists are trying to solve: Where did all of this matter come from in the first place? The Standard Model (SM) of particle physics predicts a baryon asymmetry that is much smaller than what is observed in nature. In order to try and explain this discrepancy, Sakharov (1967) postulated three necessary conditions for baryogenesis in the early universe. One of these is the requirement that charge conjugation (C) and the product of C and parity (P) symmetries are violated. Because the SM fails to generate the observed baryon asymmetry, additional sources of CP violation are needed in order to help reconcile theory and observation. Thus, physicists have been looking for extensions to the SM in search of an answer. The presence of a neutron Electric Dipole Moment (nEDM) would signal a new source of CP violation. A non-vanishing nEDM would provide evidence for the breaking of both parity (P) and time-reversal symmetry (T). Because CPT symmetry is assumed to be conserved and has not been found to be broken, this would signal CP violation.
To look for an nEDM, stored ultracold neutrons are placed in parallel and anti-parallel magnetic and electric fields and the Larmor precession frequency is carefully measured. A difference in the precession frequency of the neutrons in the two states of the fields would signal the existence of an nEDM. The current upper limit of the nEDM was set by the RAL-Sussex-ILL collaboration and stands at dn < 3.0x10-26 e cm (90% CL). Currently a new cryogenic apparatus is under construction at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL) which aims to reduce the current upper limit by two orders of magnitude.
A central problem to all neutron EDM experiments is the generation of a highly uniform and stable magnetic field. Because the suppression of systematic effects that arise from magnetic field nonuniformities and temporal drifts is vital to the success of these experiments, it is important to have the ability to precisely control and monitor the magnetic field gradients inside of the experimental volume. However, it is not always possible to measure the field gradients within the region of interest directly. To remedy this issue in the SNS nEDM experiment, a field monitoring system has been designed and tested that will allow for the reconstruction of the field gradients inside of the fiducial volume using noninvasive measurements of the field components at discrete locations external to this volume. This document will outline the theoretical framework of our method and present the results of experimental and simulated studies performed and the engineering design for such a field monitoring system.
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Nair, Nirmal-Kumar. "Incorporating voltage security into the planning, operation and monitoring of restructured electric energy markets." Texas A&M University, 2004. http://hdl.handle.net/1969.1/3199.
Повний текст джерелаАнотація:
As open access market principles are applied to power systems, significant changes
are happening in their planning, operation and control. In the emerging marketplace,
systems are operating under higher loading conditions as markets focus greater attention
to operating costs than stability and security margins. Since operating stability is a basic
requirement for any power system, there is need for newer tools to ensure stability and
security margins being strictly enforced in the competitive marketplace. This dissertation
investigates issues associated with incorporating voltage security into the unbundled
operating environment of electricity markets. It includes addressing voltage security in
the monitoring, operational and planning horizons of restructured power system.
This dissertation presents a new decomposition procedure to estimate voltage
security usage by transactions. The procedure follows physical law and uses an index
that can be monitored knowing the state of the system. The expression derived is based
on composite market coordination models that have both PoolCo and OpCo transactions,
in a shared stressed transmission grid. Our procedure is able to equitably distinguish the
impacts of individual transactions on voltage stability, at load buses, in a simple and fast
manner.
This dissertation formulates a new voltage stability constrained optimal power flow
(VSCOPF) using a simple voltage security index. In modern planning, composite power
system reliability analysis that encompasses both adequacy and security issues is being
developed. We have illustrated the applicability of our VSCOPF into composite
reliability analysis.
This dissertation also delves into the various applications of voltage security index.
Increasingly, FACT devices are being used in restructured markets to mitigate a variety
of operational problems. Their control effects on voltage security would be
demonstrated using our VSCOPF procedure. Further, this dissertation investigates the
application of steady state voltage stability index to detect potential dynamic voltage
collapse.
Finally, this dissertation examines developments in representation, standardization,
communication and exchange of power system data. Power system data is the key input
to all analytical engines for system operation, monitoring and control. Data exchange
and dissemination could impact voltage security evaluation and therefore needs to be
critically examined.
47
Treetrong, Juggrapong. "The use of parameter identification methods for the condition monitoring of electric motor drives." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498681.
Повний текст джерелаАнотація:
Induction motors are the most widely used motors among electric motors in industries. These are due to their reasonable cost, reasonably small sizes, ruggedness, low maintenance, and operation with an easily available power supply including their high reliability. However, these motors are often exposed to hostile environments during operation. These abnormal situations may lead to early deterioration of motors i.e., development of faults. Without any actions, these faults may increase to severe problems such as secondary damages to downstream equipment, unexpected breakdowns. Condition monitoring is modern technologies generally used to observe the health of electric machines regularly. Several condition monitoring methods for the induction motors have been developed using the MCSA (Motor Current Signature Analysis) and vibration analysis which explore the possibility of the early detection of developing faults in the electric machines so that the rectification can be planned in advance before any catastrophic failure. Vibration based condition monitoring requires the installation of number of vibration sensors and can detect the early fault but the quantification of the electrical faults (either in the stator or rotor or both) is generally impossible. However the other option - the MCSA doesn't require additional sensors. Hence the present research study utilized the use of the MCSA for the early detection and the quantification of faults which would be useful for quick rectification of the identified faults in practice.
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Francois, Michel M. A. Lec Ryszard. "Development of an acousto-electric biochemical sensor (AEBS) for monitoring biological and chemical processes /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2996.
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Cheng, Siwei. "Utilizing the connected power electronic converter for improved condition monitoring of induction motors and claw-pole generators." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43638.
Повний текст джерелаАнотація:
This dissertation proposes several simple, robust, and non-intrusive condition monitoring methods for induction motors fed by closed-loop inverters and claw-pole generators with built-in rectifiers. While the flexible energy forms synthesized by power electronic converters greatly enhance the performance and expand the operating region of induction motors and claw-pole generators, they also significantly alter the fault behavior of these electric machines and complicate the fault detection and protection. In this dissertation, special characteristics of the connected closed-loop inverter and rectifier have been thoroughly analyzed, with particular interest in their impact on fault behaviors of the induction motor and the claw-pole generator. Based on the findings obtained from the theoretical and experimental analysis, several sensorless thermal, mechanical, and insulation monitoring methods are proposed by smartly utilizing special features and capabilities of the connected power electronic converter.
A simple and sensitive stator turn-fault detector is proposed for induction motors fed by closed-loop inverter. In addition, a stator thermal monitoring method based on active DC current injection and direct voltage estimation is also proposed to prevent the closed-loop controlled induction motors from thermally overloading. The performance of both methods is demonstrated by extensive experimental results.
Methods to detect serpentine belt slip, serpentine belt defect, rotor eccentricity have been proposed for claw-pole generators using only the available electric sensor information. Methods to detect and protect stator turn faults in claw-pole generators are also presented in this dissertation. Lastly, a novel method to detect the generalized bearing roughness fault is proposed. All the proposed condition monitoring techniques have been validated by experimental results.
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Barber, David Edward. "Applications of phasor measurements to the real-time monitoring of a power system." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-12162009-020322/.
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