Search for dissertations about: "insulation of electric"

Showing result 1 - 5 of 41 swedish dissertations containing the words insulation of electric.

2. 1. Modelling the transient response of windings, laminated steel coresand electromagnetic power devices by means of lumped circuits : With special reference to windings with a coaxial insulation system

   Author : Pär Holmberg; Uppsala universitet; []
   Keywords : NATURAL SCIENCES; NATURVETENSKAP; Physics; Transient response; frequency response; electromagnetic transient analysis; circuit modeling; eddy currents; skin effect; windings; coils; magnetic cores; cables; electric machines; rotating electric machines; transformers; Fysik; Physics; Fysik; Electricity; Esp The Study Of Transients and Discharges; elektricitetslära; ssk studiet av transienter och urladdning;

   Abstract : Electromagnetic transients impinging on electromagnetic power devices - such as electric machines, transformers and reactors - can stress the design severely. Thus the magnitudes of the transients are often decisive for the design of the devices. Further, the operation of a device can be transient in itself. READ MORE

4. 2. Active High Voltage Insulation - A New Hybrid Insulation Concept with Dynamic and Active Features

   Author : Jörgen Blennow; Chalmers University of Technology; []
   Keywords : high voltage; surface charge; dielectric coating; charge accumulation; insulation; breakdown strength; covered electrodes; air-gap; dielectric barrier discharges;

   Abstract : In this thesis, the concept of a new environmental-friendly and high-performance high voltage insulation is presented. Basically, it is an electric field steering technique where the dynamic process of charge accumulation, actively and advantageously, re-distributes the electric field within an insulation system. READ MORE

5. 3. Dielectric Properties of Liquid-Impregnated Porous Solids

   Author : Bo Nettelblad; Chalmers University of Technology; []
   Keywords : fluid-solid interface; porous microstructure; temperature; ion-containing liquid; transport properties of porous media; brine; salinity; electric conduction; models of composite media; interface phenomena; dielectric relaxation; rock;

   Abstract : Dielectric spectroscopy is a versatile tool that can often be used as a non-destructive, indirect way of measuring other important properties (such as content of crude oil or degree of curing of a resin). The dielectric properties of materials are thus of interest in several circumstances and not only for materials used for electrical purposes (such as electrical insulation). READ MORE

6. 4. Effects of Corona and Ozone Exposure on Properties of Polymeric Materials for High Voltage Outdoor Applications

   Author : Bin Ma; Chalmers University of Technology; []
   Keywords : TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; surface resistivity; silicone rubber; nanocomposite; Outdoor insulation; ozone treatment; dielectric response; hydrophobicity; corona treatment; composite insulation; volume resistivity; ageing.; mechanical strength;

   Abstract : Despite the past four decades of service experiences with polymeric insulators in power systems all over the world, an adequate standard allowing for proper selection of polymeric materials for applications in high voltage outdoor environments has still been lacking. Therefore CIGRE Working Group D1. READ MORE

7. 5. Electrical Characterization of Partial Discharge Resistant Enamel Insulation

   Author : Tuan Anh Hoang; Chalmers University of Technology; []
   Keywords : Enamel wire insulation; dipolar polarization; charge injection; charge transport; chromium oxide; dc conductivity; partial discharge; twisted pair.; dielectric permittivity;

   Abstract : Adjustable speed drives for rotating machines have become increasingly popular as they provide possibilities of smooth and accurate process control as well as for energy savings. In such systems, due to the fact that the voltage applied at terminals of motor windings is no longer purely sinusoidal but characterized by a high content of harmonics, the appearing electrical and thermal stresses yield premature failures of the winding insulation, mainly because of an increased partial discharge (PD) activity. READ MORE