Thesis (Ph. D.)--University of Colorado, 1998. / Includes bibliographical references (leaves [302]-316).

Thesis (Ph.D.)--Drexel University, 2010. / Includes abstract and vita. Includes bibliographical references (leaves 65-70).

No description available.

The role of the dendritic tree and the way it functions within a neuron has been of interest to neurologists for over a century. As investigative techniques have become more sophisticated and thus revealing, our perception of the dendrites as being purely an information gathering component has changed to one where the dendritic tree may be viewed as a highly complex, nonlinear information processor. In spite of this most mathematical studies of the dynamical behaviour of neural populations have neglected the influence of the dendritic tree. The aim of this thesis is to address this imbalance.

Accelerated aging of 15 kV Cross-linked Polyethylene (XLPE) and Ethylene Propylene Rubber (EPR) power cables was carried out in the experiments set for the study of this thesis. The degradation of cable insulation under different aging conditions was studied and compared. The study helped to understand the effects of different factors on the aging of XLPE and EPR cable insulation. In the study, degradation of XLPE cable insulation caused by switching impulses was investigated. The deterioration of EPR cable insulation initiated by elevated ac voltage and switching impulses were also studied. Measurements of partial discharge parameters, capacitance, and dissipation factor were analyzed to evaluate the condition of cable insulation during accelerated aging process. Measurement of ac breakdown voltage provided evidence of the cables’ remaining dielectric strength after accelerated aging.

No description available.

No description available.

No description available.

This research investigates partial discharge phenomena of on-site power transmission cables of 69 kV and 161 kV by inspecting the data measured under various environments. Effective procedures and methods are suggested for estimating insulation condition of power transmission cables. To tackle the problem of interference of the environmental noises to the on-site power transmission cables, a detection method is presented based on the relationship among the amplitude, phase, and focused area of electrical signals. The difference between the outer and inner electrical signals in power transmission cable is analyzed to improve the accuracy of pattern recognition. In addition, the insulation conditions of the cable joint and the cable terminator are evaluated by comparing results of electrical and non-electrical detections. Finally, a standard procedure with some key points of inspection processes under various environments is suggested to evaluate the cable insulation degradation based on the inspection data obtained from various environments.

Att hitta fel, att kunna lokalisera och identifiera kablar i mark är en aktuell fråga då allt mer friledning ersätts med markförlagd kabel. Att snabbt lokalisera och reparera ett fel sparar pengar för energibolagen och minskar den tid kunderna är utan elförsörjning. Dagens skyddsutrustning har integrerade fellokalisering inbyggd, detta ger dock endast en ungefärlig bild av var fel finns. Mer exakt lokalisering sker med en förlokalisering, nu förtiden används pulsekometoden. En puls skickas ut på den skadade ledaren och en oskadad ledare, pulsen reflekteras i felstället och i kabelendan. Tiden från det pulserna lämnar pulsgeneratorn tills de återvänder jämförs. Detta ger avståndet till felet i meter. Där efter så används en av två efterlokaliseringsmetoder. Stötspänningsaggregat med en markmikrofon, aggregatet genererar ett överslag i felstället, urladdningen kan lokaliseras med hjälp av markmikrofonen. Andra metoden är tongenerator och en sökstav. Tongeneratorn skickar ut en högfrekvent puls på den trasiga ledaren, detta genererar ett magnetfält som kan följas med hjälp av sökstaven. När signalen försvinner så har felet lokaliserats. Kursen Elförfattning och Elinstallation (ELI 200) på Högskolan Väst saknar ett praktiskt övningstillfälle för kabellokalisering, kabelfelsökning och kabelidentifiering. Uppgiften var att ta fram en laboration, där en eller flera mätningar utförs på olika kablar i mark. Laborationen skall ingå som ett obligatoriskt moment i kursen. Målet var att laborationen skulle återspegla en verklig kabellokalisering och en kabelidentifiering. Geografiskt kommer laborationen att utföras på Magnus Åbergsgymnasiets laborationsområde i Trollhättan. Metoder att genomföra examenarbetet bestod av faktainsamling via litteratur och rapporter. Laborationsplatsen var redan förutbestämd. Kontakt med personal ifrån Magnus Åbergsgymnasiet etablerades, laborationen utformades och testades av gruppen samt oberoende part för att upptäcka eventuella brister och för att se att instruktionerna var tydliga. Ett facit med svar och referensvärden utformades och förslag på lärarhandledning skapades. På grund av begränsad tillgång av mätinstrument och av praktisk anledning begränsades laborationen till ett moment med kabellokalisering med hjälp av söksond och ett moment med kabelidentifiering. / Be able to quickly locate and identify a faulty cable and repair it is quite necessary these days, since most power-line this days are buried and power-shortages cost the energy companies a lot of money and are very irritating to the customers. Modern system are integrated whit pre-localizations equipment, the precision is not grate. To locate the problem a method of eco-localizations are deployed, a pulse in sent threw the faulty line and also threw a functional line. The pulse reflects in the fault and in the end of the line, the time deferens results in distends to the faults location. To achieve a more exact position there are two methods in use. A shock-voltage-generator produce an audible detonation in the faults location, the detonations can then be located whit a ground-microphone. The other method in use is a frequency-generator that produces a magnetic-field around the cable. The field can then be traced whit a locator-staff. When the signal disperse the approximate location of the fault is located. The course Electrical ordinance and Electrical installation lacks an applied training session regarding cable fault detection and cable identifying. The task was to develop a laboratory experiment in which one or more cables are identified and located. The lab would be included as a compulsory part of the course. The goal was that the lab would reflect a real work situation including pre-localizing, precise- localizing and in case of multiple cables, a moment of identifying the specific cable. The geographic location for the training session is pre-determined and are placed at Magnus Åbergs high school outdoor practice area in Trollhättan. Methods to carry out the thesis work consisted of gathering facts through literature, reports. The lab was designed and tested to detect any flaws. An answer key of reference values was designed and suggestions for a teacher's guide were created. The delimitations where the access to measuring instruments and fore practical reasons the advisors from University West and the representative from Magnus Åbergs high school decided to limit the training session to cable localization and cable identifying.