• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 55
  • 10
  • 2
  • 1
  • 1
  • Tagged with
  • 80
  • 80
  • 80
  • 53
  • 29
  • 11
  • 11
  • 11
  • 11
  • 9
  • 9
  • 8
  • 8
  • 8
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Probabilistic analysis of harmonics in railway traction system

Yuen, Kwok-hoo. January 2000 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 178-186).
2

Time-resolved study of third harmonic generation from anisotropically expanding clusters

Shim, Bonggu 28 August 2008 (has links)
Not available / text
3

Neutral-point-clamped shunt active filter /

Van Greunen, Corneluis Erasmus. January 2005 (has links)
Thesis (MScIng)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.
4

Time-resolved study of third harmonic generation from anisotropically expanding clusters

Shim, Bonggu, January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
5

Gate bias control and harmonic load modulation for a Doherty amplifier : a thesis presented for the degree of Doctor of Philosophy in Electrical and Computer Engineering at the University of Canterbury, Christchurch, New Zealand /

Smith, Karla. January 1900 (has links)
Thesis (Ph. D.)--University of Canterbury, 2009. / Typescript (photocopy). "2 September 2009." Includes bibliographical references (p. [139]-148) and index. Also available via the World Wide Web.
6

An investigation of the effects of voltage and current harmonics on an electrical distribution island network

Modipane, Kabelo Clifford 26 February 2009 (has links)
M.Ing. / With the advances in technology and the increase in industrial facilities, the harmonic content of an electrical network has always been a major concern among power system engineers. This is especially in an industrial environment, where the usage of power is very high as there are many large-scale types of equipment being used. Thus, it would be useful to know the sources, distortion level, impact on the power system and the equipment of harmonic currents on the harmonically rich electrical network. The presence of harmonics on electrical networks poses many problems to power system engineers and inconvenience or loss to the industries. Their effects on power system apparatus include resonance, reduced operating life of rotating machines and error in power calculations. For this study, the author would like to find out the implications of this issues, following these harmonic problems by analyzing, with some amount of simulations, practical measurements and assessments. In this way, a better understanding could be gained about these harmonic problems and harmonic contents. Steps could be taken to protect the power system equipment that could be affected by high harmonic currents and raise the quality of power supply.
7

A multiphase harmonic load flow solution technique

Xu, Wenyuan January 1990 (has links)
This thesis presents a comprehensive solution technique for power system harmonic analysis with unbalanced load flow conditions. It is based on multiphase modelling of the system in phase quantities. Two of the most important features of this technique are the multiphase approach to the harmonic load flow problem, and the capability to add component nonlinearities easily. The first feature allows the technique to be used for either single-phase or three-phase, and for either balanced or unbalanced harmonic analysis. The second feature allows the later addition of power electronic device models. The technique is simple in concept. The nonlinear elements are first modelled as harmonic Norton equivalent circuits based on the network load flow conditions. These linear circuits are then included in the network solution with multiphase load flow constraints and network unbalances. Once the new load flow solutions are obtained, improved Norton equivalent circuits can be calculated, which in turn are used for improved network solutions. The entire solution scheme is therefore iterative, and stops when certain convergence criteria are met. The unbalanced harmonics from nonlinear inductors, synchronous machines and static compensators with thyristor-controlled reactors are studied in this thesis. The convergence properties of the technique are investigated with test cases and theoretical analysis. In addition to the harmonic load flow analysis, this technique can also be used as an improved initialization procedure for the Electromagnetic Transient Program (EMTP). / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate
8

Harmonic impedance estimation of a power system implementing frequency domain measurement techniques

13 August 2012 (has links)
M.Ing. / The increased used of non-linear loads within the power system during recent years have resulted in deviations from the perfect sinusoidal voltage and current waveform. This deviation from the perfect sinusoidal waveform can be expressed according to Fourier analysis by a set of co-sinusoidal waveforms having frequencies, which are a multiple of the fundamental frequency, referred to as harmonics. Non-linear loads are generally characterised by harmonic currents. It is therefore often preferred to express the harmonic emission limits in terms of harmonic currents rather than harmonic voltages. In order to translate the harmonic currents into harmonic voltages the harmonic impedance of the power system must be known. The power system's harmonic impedance can be assessed via computational, simulation and measurement techniques. The study will concentrate on the estimation of the harmonic impedance of a 33kV power system by implementing two online frequency domain measurement techniques. Both techniques are applied at the point of delivery of a dominant nonlinear load during normal and energisation load conditions with its power factor correction capacitor bank in and out off service. The estimated harmonic impedance is then compared with the calculated and simulated harmonic impedance.
9

Probabilistic analysis of harmonics in railway traction system

阮國豪, Yuen, Kwok-hoo. January 2000 (has links)
published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy
10

Harmonic analysis of power systems connected to converter substations

Christoforidis, George P. 05 1900 (has links)
No description available.

Page generated in 0.0928 seconds