Teses / dissertações sobre o tema "Electric lines"
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Sa, Yingshi 1965. "Reliability analysis of electric distribution lines". Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29546.
Texto completo da fonteThe goal of this thesis is to use the FORM/SORM algorithm to evaluate the reliability of a single pole and the results obtained when applied to a sample of 887 wood poles inspected in the field. The procedure was also applied to a sample of poles designed according to the current codes in order to calibrate the evaluation procedure. The results indicate that the proposed procedure will improve the current maintenance and replacement strategy by guarantying a more uniform level of reliability throughout the network and by decreasing by up to 33% the number of wood pole replacements. (Abstract shortened by UMI.)
Kryukova, N. V., Evgen Viktorovych Goncharov e I. V. Polyakov. "Modern monitoring systems of electric power lines". Thesis, NTU "KhPI", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/38909.
Texto completo da fonteBernardin, Sylvie. "Étude et analyse du délestage de glace atmospherique sur les cables /". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1989. http://theses.uqac.ca.
Texto completo da fonteFernandez-Ramirez, Eder-Ernesto. "Optimisation du taux de compensation série d'une longue ligne de distribution : cas de l'Hydro-Québec : Abitibi Téminscamingue [sic] /". Thèse, [Chicoutimi : Rouyn : Université du Québec à Chicoutimi] Université du Québec en Abitibi-Témiscamingue, 2006. http://theses.uqac.ca.
Texto completo da fonteBibliogr.: f. 136-139. Document électronique également accessible en format PDF. CaQCU
Kleinhans, Kevin. "Investigation into possible mechanisms of light pollution flashover of 275kv transmission lines as a cause of unknown outages". Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1071.
Texto completo da fonteKobziev, V., e E. Krasowski. "Some lines of energysaving in electric power industry". Thesis, ДРУКАРНЯ МАДРИД, 2016. http://openarchive.nure.ua/handle/document/8409.
Texto completo da fonteMercer, Douglas. "Thor's hammer deflected : a history of the protection of power systems from lightning, with special reference to Queensland, 1950 to 1995 /". [St. Lucia, Qld.], 2001. http://adt.library.uq.edu.au/public/adt-QU20020712.164134/index.html.
Texto completo da fonteJerrell, Jeffrey W. "Critical span analysis of overhead lines". Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/16430.
Texto completo da fonteDe, Villiers Wernich. "Prediction and measurement of power line carrier signal attenuation and fluctuation". Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52410.
Texto completo da fonteENGLISH ABSTRACT: A frequency domain Power Line Carrier (PLC) simulation program, with the ability to simulate signal attenuation including the coupling equipment, was developed. This simulation program was put to the test against the independent program of Professor L.M. Wedepohl and against practical field measurements. The predictions of the two programs were in precise agreement for a wide range of input parameters. Results from the field tests and predictions also showed close agreement. Further investigations, applying the simulation program, explained how ground conductors and soil resistivity influences PLC signal propagation. An experiment, which was developed to monitor PLC signal attenuation, was installed on the PLC system between Koeberg power station and Acacia substation, both near Cape Town. Data logged continuously over 28 days, indicated measurable and deterministic PLC signal attenuation variations with typical time constants of a few hours. Simulations of the PLC system indicated that the signal amplitude variations were influenced by changes in the height above the ground plane of the phase conductor. This significant finding creates the possibility to obtain real time knowledge of the sag of an Over Head Transmission Line (OHTL) by exploiting an operational PLC system. The knowledge about real time sag can be used in economical dynamic ampacity control systems. The practical and financial benefits to the electricity supply and distribution industry can be significant.
AFRIKAANSE OPSOMMING: 'n Frekwensie gebied "Power Line Carrier" (PLC) simulasie program wat die sein verswakking en die koppeling verliese kan naboots, is ontwikkel. Die program is getoets teen die onafhanklike program van Professor L.M. Wedepohl asook praktiese metings in die veld. Die vooruitskatings van beide programme is presies die selfde vir 'n wye reeks van parameters. Metings en nabootsings het ook noue ooreenstemming getoon. Verdere ondersoek, m. b. v. die program, is gedoen ten einde te verduidelik hoe grond-geleiers en grond weerstand die PLC sein se voortplanting beïnvloed. 'n Eksperiment om die PLC sein se verswakking mee te monitor is ontwerp. Die eksperiment was geïnstalleer in die PLC stelsel tussen Koeberg kernkragstasie en Acacia substasie, naby Kaapstad. Die eksperiment was vir 28 dae geaktiveer en die data wat die eksperiment opgelewer het toon meetbare PLC sein verswakking met tyd konstantes van 'n paar uur. Verdere nabootsings het gewys dat die veranderende verswakking in die PLC seinsterkte toegeskryf kan word aan die wisseling in hoogte van die fase geleiers bo die grondvlak. Hierdie bevinding is van besondere belang aangesien dit die moontlikheid oopmaak om die gemiddelde sak van kraglyne in reële tyd en onder bedryfs toestande te kan meet. Die informasie van die reële sak van kraglyne kan gebruik word in effektiewe stroomdrae-vermoë beheer stelsels. Die praktiese en finansiële voordele wat krag voorsieners en verspreiders hieruit kan put kan aansienlik wees.
Naredo, V. José Luis A. "Communication frequency response of high voltage power lines". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26725.
Texto completo da fonteApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Cecchi, Valentina Miu Karen Nan. "A modeling approach for electric power transmission lines in the presence of non-fundamental frequencies/". Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2583.
Texto completo da fonteDirkse, van Schalkwyk W. J. "The placing of line surge arresters and fuses on 11 and 12 kV lines to protect equipment against lightning". Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52553.
Texto completo da fonteENGLISH ABSTRACT: Unshielded distribution lines has a poor performance during lightning activity. Lightning initiates flashovers between the phases and earth and causes line breakers to trip several times during a lightning storm. In addition equipment like fuses, surge arresters and transformers are damaged by lightning and cause in some cases long power interruptions to customers. The application of line surge arresters on distribution lines is a solution that is implemented worldwide to limit the lightning related problems. This thesis investigated using line surge arresters in conjunction with bushing-mount fuses to decrease nuisance fusing and transformer damage during lightning activity. Two new pieces of equipment (dropout surge arresters and transformer bushingmount fuses) were developed and strategically placed on 4 different distribution lines. Equipment failures decreased by 90 % while financially the project had an excellent return on investment.
AFRIKAANSE OPSOMMING: Distribusie lyne sonder skermdrade presteer swak gedurende weerlig aktiwiteit. Weerlig veroorsaak oorvonking tussen fases en aard geleiers wat lei tot breker klinke. Transformators, sekerings, stuwingsafleiers en ander toerusting word ook deur weerlig beskadig en veroorsaak in sommige gevalle lang toevoer onderbrekings. Installering van lyn stuwingsafleiers op distribusielyne is 'n metode wat wêreldwyd gebruik word om oorvonking en weerligskade te beperk. Hierdie tesis ondersoek die installering van lyn stuwingsafleiers en deurvoerder gemonteerde sekerings om transformator skade en onnodige blaas van sekerings te beperk tydens weerlig aktiwiteit. Nuwe toerusting (uitval stuwingsafleiers en transformator deurvoerder gemonteerde sekerings) was ontwikkel en strategies op 4 verskillende distribusie lyne geïnstalleer. 'n Negentig persent vermindering in toerusting beskadiging is behaal terwyl die projek finansiël 'n goeie opbrengs op belegging meegebring het.
Chen, Shelley L. "Programs for calculating high temperature ampacity and sag for overhead electrical conductors". Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/17933.
Texto completo da fonteDale, Joel Kelly. "Electric field lines and voltage potentials associated with graphene nanoribbon". Thesis, University of Iowa, 2013. https://ir.uiowa.edu/etd/2471.
Texto completo da fonteMullen, W. Grigg. "An evaluation of the utility of four in-situ test methods for transmission line foundation design /". This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-07112007-092850/.
Texto completo da fonteDu, Toit Nicolaas Serdyn. "Calibration of UV-sensitive camera for corona detection". Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/1016.
Texto completo da fontePéter, Zsolt. "Modelling and simulation of the ice melting process on a current-carrying conductor = Modélisation et simulation de processus de délestage de glace par fonte sur un conducteur en présence de courant /". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2006. http://theses.uqac.ca.
Texto completo da fonteLa p. de t. porte en outre: Thèse présentée à l'Université du Québec à Chicoutimi pour l'obtention du doctorat en ingénierie. CaQCU Bibliogr.: f. 260-264. Document électronique également accessible en format PDF. CaQCU
Tong, Sai-kit. "A computer-aided measurement system for monopolar high-voltage direct-current coronating lines /". [Hong Kong] : University of Hong Kong, 1986. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12321771.
Texto completo da fonteSwapnil, Muhammad Mubassir. "Computing effects of electric and magnetic fields near overhead transmission lines". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63023.
Texto completo da fonteApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Tiancheng, Zhang, e Zhang Yunlin. "High voltage Direct Current lines in the Chinese electric power system". Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-12757.
Texto completo da fonteDavalbhakta, Aneesh. "Improved configurations of sensors for the measurement of tower footing resistance a thesis presented to the faculty of the Graduate School, Tennessee Technological University /". Click to access online, 2008. http://proquest.umi.com/pqdweb?index=0&did=1597632921&SrchMode=1&sid=4&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1279309880&clientId=28564.
Texto completo da fonteMcWhorter, Bruce Burnett. "Transient temperature distributions in short-circuited electrical conductors". Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/15951.
Texto completo da fonteYang, Lifeng. "Computer relaying for EHV/UHV transmission lines". Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/40085.
Texto completo da fontePh. D.
湯世傑 e Sai-kit Tong. "A computer-aided measurement system for monopolar high-voltage direct-current coronating lines". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1986. http://hub.hku.hk/bib/B31207467.
Texto completo da fonteNavaratnam, Srivallipuranandan. "Series impedance and shunt admittance matrices of an underground cable system". Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26726.
Texto completo da fonteApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Marti, Luis. "Simulation of electromagnetic transients in underground cables with frequency-dependent modal transformation matrics". Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/27442.
Texto completo da fonteApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Olsen, Anders Tuhus. "Voltage Upgrading of Overhead Lines". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11218.
Texto completo da fonteGuesdon, Cyril. "Etudes des répartitions des événements de verglas et de givre à travers le Québec /". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2000. http://theses.uqac.ca.
Texto completo da fonteLeonard, Ronald William. "Application of the Monte Carlo method to the estimation of the risk of failure of transmission line insulation". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28496.
Texto completo da fonteApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Crowder, Michael R. "Assessment of devices designed to lower the incidence of avian power line strikes /". PURL image only, 2000. http://www.arlis.org/docs/vol1/62243427.pdf.
Texto completo da fonteCokkinides, George J. "Frequency dependent transmission line modeling with grounding representation". Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/15494.
Texto completo da fonteSavoullis, Yiannakis C. "Experimental verification and modification of a real-time ampacity program for overhead conductors". Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/17840.
Texto completo da fonteLi, Quan. "AC loss characteristics of monolayer and multilayer superconducting power transmission cables". Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609500.
Texto completo da fonteFilipovic-Gledja, Visnja. "A probability based unified model for predicting electrical, mechanical and thermal characteristics of stranded overhead-line conductors". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30086.pdf.
Texto completo da fonteCrnojacki, Zorica. "Extra high voltage transmission corridor siting : technical, public, institutional and regulatory considerations /". Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-10032007-171749/.
Texto completo da fonteLi, Xiaojuan. "Estimations of power system frequency, phasors and their applications for fault location on power transmission lines". University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0125.
Texto completo da fonteGueye, Babacar Salif. "Suitability of Casuarina equisetifolia as utility poles in Senegal". Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-01102009-063410/.
Texto completo da fonteWells, M. Glenn. "Transient temperature distributions in overhead fiber-optic ground wires". Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/16885.
Texto completo da fonteLi, Xiaoyong. "Added CFO voltages from fiberglass poles and its electrical degradation". Master's thesis, Mississippi State : Mississippi State University, 2001. http://library.msstate.edu/etd/show.asp?etd=etd-11092001-113706.
Texto completo da fonteBao, Yufei. "Integrated optical tapped-delay-lines : design, analysis and implementation". Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/15446.
Texto completo da fonteAdamov, Minja Gemisic. "Measurements of local electric fields by doppler-free laser spectroscopy of hydrogen resonance lines". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2007. http://dx.doi.org/10.18452/15576.
Texto completo da fonteA method for electric field measurements that observes the Stark spectra of the low excited levels n = 2 and n = 3 of atomic hydrogen has been explored in this work. As advantage these levels can be excited Doppler-free from the ground state by a single laser and the highly resolved Stark spectra are easy to understand and to be calculated. Good sensitivity of electric field measurements is achieved with specially designed solid state laser systems, which provide tuneable pulsed UV radiation with a high pulse peak-power and a narrow bandwidth needed for Doppler-free two-photon excitation. Using hydrogen and deuterium the Stark spectra of the n = 2 level are detected as optogalvanic signal. For three different cases of laser polarization the n = 3 spectra of hydrogen are measured simultaneously with optogalvanic and laser induced Balmer alpha fluorescence detection. Electric fields down to 200 V/cm can be determined from the Stark spectra of n = 2 level, while the spectra of n = 3 level enable measurements of electric fields as small as 50 V/cm in each of the three cases of laser polarization.
Coggins, David Paul. "Single-ended traveling wave fault location on radial distribution lines". Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/27951/.
Texto completo da fonteSellers, Sally M. "Caculation of ampacity for underground electrical cables". Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/18973.
Texto completo da fonteLiao, Jen-Chyi. "Computer simulation of multiple coupled transmission lines in electronic packaging application". Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184659.
Texto completo da fonteChen, Shuoqi. "Characterization of semiconductor-based guided wave structures using field theoretical analysis techniques". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21927.pdf.
Texto completo da fonteVisser, Abraham Johannes. "Transformerless series dip/sag compensation with a multilevel cascaded inverter". Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52592.
Texto completo da fonteENGLISH ABSTRACT: This thesis covers the development of a multilevel cascaded inverter for the purpose of costeffective transformerless series dip compensation. Of all known power quality problems, voltage dips are the greatest reason for concern. Dips/sags occur more frequently than outages and therefore tend to be more costly for industry as modem technical equipment becomes all the more sensitive to the quality and reliability of supply. A number of devices already exist to compensate for this problem, but the cost of most of these systems does not always justify the financial losses they compensate for. All of these systems are using transformers and/or large filter components that contribute to the size, price and losses to quite a large extent. Series injection dip compensators offer the advantage of only having to compensate for the decrease in supply voltage during a dip. This results in a significant reduction in the converter ratings and energy storage requirements compared to conventional uninterruptible power supplies or shunt injection power quality devices. Existing inverter topologies, including multilevel inverters, were therefore studied and compared as possible solutions for cost-effective transformerless series dip compensation. On the basis of these considerations the multilevel cascaded inverter seems to be the most cost-effective option. The relatively low harmonic content of its unfiltered output also eliminates the need for a large output filter. A single-phase dip compensator, with this topology, was designed and built according to specifications stated by Eskom, the main utility in South Africa. Batteries as energy storage and automotive MOSFETs as switching components, proved to be most cost-effective options for the specified power ratings. Control algorithms for dip compensation with the multilevel inverter were also developed. Some of these algorithms are based on existing techniques, but two new algorithms were also developed to implement force commutation of the thyristors and to share the power dissipation in the dip compensator. Simulations indicated that these algorithms could be suitable and sufficient for their application. This dip compensator with its control algorithms was tested with a dip generator, developed at the University of Stellenbosch, for different types of loads. The experimental results confirmed the simulations and showed a very good performance for the specified conditions. An optimised design of this dip compensator will make it a cost-effective solution for dip compensation.
AFRIKAANSE OPSOMMING: Hierdie tesis dek die ontwikkeling van 'n multivlakwisselrigter, in kaskade, met koste-effektiewe transformatorlose duik kompensasie as mikpunt. Van al die bekende toevoerkwaliteit probleme wek duike in die spanning die meeste kommer. Duike kom meer gereeld voor as kragonderbrekings en neig daarom om 'n groter onkoste te wees vir die industrie soos wat moderne tegnologiese toerusting al hoe meer sensitief raak vir die kwaliteit en betroubaarheid van die toevoer. 'n Aantal toestelle wat vir hierdie probleem kompenseer bestaan reeds, maar die koste van hierdie stelsels regverdig nie altyd die finansiële verliese wat hulle moet elimineer nie. Al hierdie stelsels gebruik transformators en/of groot filter komponente wat grootliks bydra tot die grootte, prys en verliese van hierdie stelsels. Serie-injeksie kompenseerders het die voordeel dat hulle net kompenseer vir die verlies in die toevoerspanning tydens die duik. Dit het 'n beduidende vermindering in die omsetterkenwaardes en energiestoorvereistes tot gevolg in vergelyking met ononderbroke kragbronne (UPS) of newe-injeksie toevoerkwaliteit toestelle. Daarom IS bestaande wisselrigtertopologië, insluitende multivlakwisselrigters, bestudeer en vergelyk as moontlike oplossings vir koste-effektiewe serie duik-kompensasie. Van al hierdie moontlikhede lyk die multivlakwisselrigter, in kaskade, na die mees koste-effektiewe opsie. Die relatiewe lae harmoniese inhoud van sy ongefilterde uittree elimineer die behoefte aan 'n groot uittreefilter. 'n Enkelfase duik kompenseerder, met hierdie topologie, is ontwerp en gebou volgens die spesifikasies wat vasgestel is deur Eskom, die hoof elektriese kragvoorsiener in Suid-Afrika. Dit het geblyk dat batterye, en MOSFETte uit die motorbedryf, die mees koste-effektiewe opsies bied vir onderskeidelik die energiestoor en skakelkomponente. Beheeralgoritmes VIr duik kompensasie met die multivlakwisselrigter is ook ontwikkel. Sommige van hierdie algoritmes is gebaseer op bestaande tegnieke, maar twee nuwe algoritmes is ook ontwikkel vir die kommutering van die tiristors en die deling van die drywingsverkwisting in die duik kompenseerder. Simulasies dui aan dat hierdie algoritmes geskik en voldoende kan wees vir hulle toepassing. Hierdie duik kompenseerder met sy beheeralgoritmes is getoets vir verskillende tipes laste met 'n duikgenerator wat ontwikkel is by die Universiteit van Stellenbosch. Die eksperimentele resultate bevestig dit wat verkry is uit die simulasies en wys 'n goeie werkverrigting vir die gespesifiseerde kondisies. 'n Geoptimeerde ontwerp van hierdie duik kompenseerder sal dit 'n koste-effektiewe oplossing maak vir duik kompensasie.
Matandirotya, Electdom. "Measurement and modelling of geomagnetically induced currents (GIC) in power lines". Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2459.
Texto completo da fonteGeomagnetically induced currents (GIC) are currents induced in ground-based conductor networks in the Earth's surface. The GIC are driven by an electric eld induced by geomagnetic variations which are a result of time-varying magnetospheric-ionospheric currents during adverse space weather events. Several studies have shown that there is a likelihood of technological damage (the power grid) in the mid- and low-latitude regions that could be linked to GIC during some geomagnetic storms over the past solar cycles. The effects of GIC in the power system can range from temporary damage (e.g. protective relay tripping) to permanent damage (thermal transformer damage). Measurements of GIC in most substations are done on the neutral-to-ground connections of transformers using Hall-effect transducers. However, there is a need to understand the characteristics of GIC in the power lines connected to these transformers. Direct measurements of GIC in the power lines are not feasible due to the low frequencies of these currents which make current measurements using current transformers (CT) impractical. This thesis discusses two techniques that can be employed to enhance understanding GIC characteristics in mid-latitude regions. The techniques involve the measurement of GIC in a power line using differential magnetometer measurements and modelling GIC using the finite element method. Low frequency magnetometers are used to measure magnetic felds in the vicinity of the power lines and the GIC is inferred using the Biot-Savart law. A finite element model, using COMSOL-Multiphysics, is used to calculate GIC with the measured magnetic field and a realistic Earth conductivity profile as inputs. The finite element model is used for the computation of electric field associated with GIC modelling.
Schilder, Melanie. "Wideband modelling of capacitive voltage sensors for open-air transmission line applications". Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/53222.
Texto completo da fonteENGLISH ABSTRACT: This dissertation considers the wideband modelling of capacitive voltage sensors for open-air transmission line applications. Two novel topologies were introduced, namely a differential parallel plate sensor with a floating faraday cage for the interface instrumentation and a coaxial sensor mounted around the earth conductor with a faraday cage connected to the earth conductor. The modelling and analysis procedures included the derivation of equivalent circuit models in order to simulate the calibration factor, the loading effect of the interface instrumentation and the effect of leakage to ground, both in the time- and frequency domain. In order to obtain a flat frequency response from very low frequencies (less than 5 Hz) to very high frequencies (several MHz) it is important that the interface instrumentation have a high input impedance and galvanic isolation be maintained. This was achieved by developing interface instrumentation with a fibre-optic link operated from battery power. The instrumentation represents a fairly unique approach in that the data is digitised before transmission across the serial fibre-optical link, where-as conventional interfaces use analogue optical technology. Despite the added complexity and high power requirements introduced by the digitising process, the improved versatility is expected to yield a superior interface solution. The instrumentation has a bandwidth of approximately 6 MHz, with an optional anti-aliasing filter at 1 MHz. Special consideration should be given to the support structure as any unbalanced leakage to ground will introduce variations in the frequency response towards the low-frequency end. Leakage of a 100 MQ was found to influence the frequency response of the circuit up to frequencies of 1 kHz. Extensive simulation studies were conducted to obtain qualitative and quantitative insight into the differential sensor topology and the associated electric fields. The improvement of a differential plate sensor over the traditional single element plate sensor was demonstrated using twodimensional simulations. Further simulations with a three-dimensional package showed that the two-dimensional simulations are insufficient, because the boundary conditions and end effects have a great influence on the calibration factor of the sensor. Extensive laboratory tests were also undertaken to evaluate the sensor topology as well as the effects of the interface instrumentation and leakage to ground. Excellent correlation were found between the measured and simulated waveforms, both in the time- and frequency domains regarding the calibration factor as well as the added poles or zeros at low frequencies. It can therefore be deduced that a valid circuit model was suggested for these sensor topologies in the frequency range from 10 Hz to 1 MHz. Keywords: Capacitive sensors, Open-air voltage sensors
AFRIKAANSE OPSOMMING: Hierdie verhandeling beskou die wyeband modellering van kapasitiewe spanningsensors vir opelug transmissie lyn toepassings. Twee oorspronklike topologieë is voorgestel, naamlik 'n differensiële parallel plaat sensor met 'n aparte faraday hok vir die koppelvlak instrumentasie en 'n koaksiale sensor wat rondom die aardgeleier monteer word met die faraday hok ook aan die aardgeleier gekoppel. Die modellerings en analise prosedures het ingesluit die afleiding van ekwivalente stroombaanmodelle vir simulasie van die kalibrasiefaktor asook die belasingseffek van die koppelvlak instrumentasie en lekweerstand na grond in beide die tyd- en frekwensie gebiede. Om 'n plat frekwensieweergawe te verkry vanaf baie lae frekwensies (laer as 5 Hz) tot by baie hoë frekwensies Cn paar MHz), is dit belangrik dat die koppelvlak instrumentasie 'n hoë intreeimpedansie het en galvaniese isolasie verseker word. Dit was bereik deur koppelvlak instrumentasie te ontwikkel met 'n optiese vesel koppeling wat met battery krag aangedryf word. Die instrumentasie verskaf 'n redelik unieke aanslag in die opsig dat die data gemonster word voordat dit oor die seriële optiese vesel skakel gestuur word, terwyl konvensionele koppelvlakke analoog optiese tegnologie gebruik. Ten spyte van die toegevoegde kompleksiteit en hoë drywingsvereistes van die versyferingsproses, het die instrumentasie se veelsydigheid toegeneem tot die mate dat dit as 'n beter koppelvlak oplossing beskou word. Die instrumentasie het 'n bandwydte van ongeveer 6 MHz, met 'n opsionele teen-vou filter by 1 MHz. Die ondersteuningstruktuur is van besondere belang aangesien enige ongebalanseerde lekweerstand na grond afwykings in die frekwensieweergawe sal veroorsaak aan die lae frekwensie kant. Lekweerstand van 100 MQ sal die frekwensieweergawe beïvloed tot by ongeveer 1 kHz. Uitgebreide simulasies is gedoen om kwalitatiewe en kwantitatiewe insig in die differensiële sensor topologie en die geassosieerde elektriese velde te verkry. Die verbetering van 'n differensiële parallel plaat sensor in vergelyking met die tradisionele enkel element plaat sensor is demonstreer met twee-dimensionele simulasies. Verdere simulasies met 'n drie-dimensionele pakket het gewys dat die twee- dimensionele simulasies onvoldoende is aangesien grensvoorwaardes en randeffekte 'n groot invloed het op die kalibrasiefaktor van die sensor. Uitgebreide laboratorium toetse is ook gedoen om die sensor topologie sowel as die effekte van die koppelvlak instrumentasie en lekweerstand na grond te evalueer. Uitstekende korrelasie is gevind tussen gemete en voorspelde golfvorms, in beide die tyd- en frekwensie gebied met betrekking tot die kalibrasie faktor sowel as die toegevoegde pole en zeros by lae frekwensies. Die gevolgtrekking is dus dat 'n geldige stroombaanmodel voorgestel is vir die sensor topologieë vir die frekwensie bereik van 10Hz to 1 MHz. Sleutelwoorde: Kapasitiewe sensors, Ope-lug spanningsensors
Markovic, Dejan. "Induced currents in gas pipelines due to nearby power lines". Access electronically, 2005. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060807.155002/index.html.
Texto completo da fonteChan, Morgan Hing Lap. "Channel characterization and forward error correction coding for data communications on intrabuilding electric power lines". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29071.
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