• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 3
  • 2
  • 1
  • Tagged with
  • 12
  • 12
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 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

Power quality programme awareness : framework for developing countries

Sultan, Saad Saleh January 2013 (has links)
In recent years, Power Quality Programmes (PQPs) have become one of the most recent services offered to electrical distribution companies, both private and state suppliers. This is due to the sudden increase in the number of concerns over power quality (PQ) problems. The aim of this research is to study the implementation of a PQP framework, and the obstacles and barriers faced by Libyan Distribution Networks (LDNs) in implementing a PQP. Firstly, to identify the most critical success factors that would have a major impact on PQP implementation in LDNs. Five Critical Success Factors (CSFs) for PQP were identified to examine the level of power quality in LDNs. They are PQ awareness, PQ disturbances, PQ management commitment, PQ employee’s participation and training and PQ customers’ satisfaction. It revealed that all five CSFs were significantly affected by the level of PQ awareness, and the suspension of PQP implementation. An appropriate PQP framework was developed for the purpose of this study to guide LDNs as a case study in developing countries. The proposed PQP framework model was validated based on the identified CSFs, and the barriers and benefits of PQP, which were analysed using different techniques based on both SPSS and NVivo software. The PQP framework was developed from the findings based on the responses of 397 PQ survey participants, and supported by 44 face-to-face semi-structured interviews conducted with professionals and expert LDNs staff. Out of the 16 PQP barriers, 13 were statistically significant, which indicated that Libya distribution systems have already surmounted various barriers to implementing a PQP effectively. The developed PQP framework consisted of three essential phases. Phase one is designed to increase the level of awareness, while phase two involves preparation for PQP, which contains seven crucial requirements. Phase three, which is the implementation, is designed to determine both the weaknesses and obstacles, and is designed to increase the awareness level. This framework encourages and guides the implementation teams to have an obvious and clear awareness and vision of how to prevent existing obstacles from reappearing in different forms, leading to long-term PQP improvements. There were 11 overall benefits of PQP implementation, which would have a positive impact on LDNs.
2

A framework for the development of generic virtual reality systems

Sen, Ramen January 1998 (has links)
No description available.
3

Investigation Of Multilevel Inverters For D-statcom Applications

Deniz, Mustafa 01 December 2009 (has links) (PDF)
The most important advantages of Multilevel Inverters are the absence of a coupling transformer for medium voltage applications and low harmonic current content. In this way, relocatable and economical STATCOM systems can be realized. Complex control algorithms and the isolation problems of measurement devices and power supplies are the main challenging parts of this type of application. In this study, the design, realization, and the performance of a Voltage Source Type Cascaded Multilevel Converter Based STATCOM will be investigated in terms of digital computation, control hardware and the semiconductors devices commercially available in the market. This research work is fully supported by the Public Research Grant Committee (KAMAG) of TUBiTAK within the scope of National Power Quality Project of Turkey with the project No: 105G129.
4

Design And Implementation Of A Current Source Converter Based Statcom For Reactive Power Compensation

Bilgin, Faruk Hazim 01 April 2007 (has links) (PDF)
This research work is devoted to the analysis, design and development of the first medium power Current-Source Converter (CSC) based distribution-type Static Synchronous Compensator (D-STATCOM) with simplest converter topology and coupling transformer connection. The developed CSC-D-STATCOM includes a +/-750kVAr full-bridge CSC employing Selective Harmonic Elimination Method (SHEM), a 250kVAr low-pass input filter at 1kV voltage level, and a &amp / #916 / /Y connected coupling transformer for connection to medium-voltage load bus. The power stage of CSC is composed of series connection of natural air-cooled high-voltage IGCT switched at 500 Hz for the elimination of four lowest current harmonic components (5th, 7th, 11th, 13th), and optimized fast recovery high voltage diode in each leg. Reactive power control is achieved by applying the phase shift angle control at fixed modulation index, which is implemented digitally on a DSP microcontroller. The developed system has been implemented for compensation of rapidly varying reactive power demand of coal mining excavators in Turkish Coal Enterprises. The field test results have shown that the proposed CSC D-STATCOM serves as a technologically new full substitute of conventional Voltage-Source Converter based D-STATCOM having complex transformer connections in view of relatively fast response in reactive power compensation, very low total demand distortion factors, complying with the IEEE Std. 519-1992 even for the weakest power systems, and acceptable efficacy figures.
5

Návrh koncepce kompenzace jalového výkonu v průmyslové síti / Design of reactive power compensation in distribution network

Popek, Jiří January 2012 (has links)
This thesis is about reactive power compensation in industrial network. Task is design reactive power compensation devices, so that the power factor, which is main indicator of power quality, was within the limits required by the distributor. This is applied to wholesale customers of electrical energy. Reactive power consumed by appliances increased the current that flows through the network, transmission losses and voltage drop. Reactive power compensation is a measure reducing load current and ohmic losses in a supply line. Given that the compensation is one of the significant cost-saving measures in electric power distribution. Distributor requires electric power consumption with a lagging power factor in the range from 0,95 to 1. Other values of power factor are penalized.
6

Model zátěže / Load model

Lašo, Matej January 2016 (has links)
This thesis deals with power quality and load modeling. The issues of power quality, principles of load model creation and various types of loads and their principles are described and explained in this thesis. Various software and its main adventages in power systems modeling are described and various load models and simulations in PSCAD program are created and described at last.
7

Diagnóstico sobre a utilização das lâmpadas fluorescentes compactas (LFC) como promotoras de eficiência energética nos sistemas de iluminação no Brasil / Diagnosis about the use of compact fluorescent lamps (CFL) as promoting energy efficiency in lighting systems in Brazil.

Cintia Gonçalves Mendes da Silva 20 February 2008 (has links)
O aumento do consumo no Brasil aparte com problemas de abastecimento de energia elétrica na década de 90, durante um período de más condições hidrológicas causou uma preocupação e instou uma pesquisa sobre as formas de redução do consumo. A qualidade de energia não era uma prioridade, cargas não eram tão sensíveis, nem os processos existentes exigiam tanto na qualidade do fornecimento de energia elétrica. A preocupação sobre a qualidade do abastecimento de energia aumentou, principalmente no setor industrial, com o aumento da concorrência nos mercados nacionais e no exterior. A qualidade e a quantidade da produção tornaram-se um item para distinguir o lucro. Desta forma, a qualidade do fornecimento de energia e a continuidade das linhas de produção tornaram-se mais importante. Este trabalho pretende mostrar resultados de um estudo experimental sobre lâmpadas fluorescentes compactas com reator integrado, e algumas conseqüências da sua utilização generalizada. / The increase of the consumption in Brazil aside with problems of supply of electrical energy in the decade of 90, during a period of bad hydrological conditions caused a concern and urged a search for ways of reduction of the consumption. The quality of power was not a priority, loads were not so sensitive nor the existing processes demanded as much as quality of the supply of electric energy. The concern on quality of energy supply increased, mainly in the industrial sector, with the increase of the competition in the domestic markets and overseas. The quality and the amount of production became a distinguished item for the profit. In this way, the quality of energy supply and the continuity of the production lines became more important. This work aims to show results of an experimental survey about compact fluorescent light bulbs with integrated reactor, and some consequences of its generalized use.
8

Diagnóstico sobre a utilização das lâmpadas fluorescentes compactas (LFC) como promotoras de eficiência energética nos sistemas de iluminação no Brasil / Diagnosis about the use of compact fluorescent lamps (CFL) as promoting energy efficiency in lighting systems in Brazil.

Silva, Cintia Gonçalves Mendes da 20 February 2008 (has links)
O aumento do consumo no Brasil aparte com problemas de abastecimento de energia elétrica na década de 90, durante um período de más condições hidrológicas causou uma preocupação e instou uma pesquisa sobre as formas de redução do consumo. A qualidade de energia não era uma prioridade, cargas não eram tão sensíveis, nem os processos existentes exigiam tanto na qualidade do fornecimento de energia elétrica. A preocupação sobre a qualidade do abastecimento de energia aumentou, principalmente no setor industrial, com o aumento da concorrência nos mercados nacionais e no exterior. A qualidade e a quantidade da produção tornaram-se um item para distinguir o lucro. Desta forma, a qualidade do fornecimento de energia e a continuidade das linhas de produção tornaram-se mais importante. Este trabalho pretende mostrar resultados de um estudo experimental sobre lâmpadas fluorescentes compactas com reator integrado, e algumas conseqüências da sua utilização generalizada. / The increase of the consumption in Brazil aside with problems of supply of electrical energy in the decade of 90, during a period of bad hydrological conditions caused a concern and urged a search for ways of reduction of the consumption. The quality of power was not a priority, loads were not so sensitive nor the existing processes demanded as much as quality of the supply of electric energy. The concern on quality of energy supply increased, mainly in the industrial sector, with the increase of the competition in the domestic markets and overseas. The quality and the amount of production became a distinguished item for the profit. In this way, the quality of energy supply and the continuity of the production lines became more important. This work aims to show results of an experimental survey about compact fluorescent light bulbs with integrated reactor, and some consequences of its generalized use.
9

Design And Implementation Of A Voltage Source Converter Based Statcom For Reactive Power Compensation And Harmonic Filtering

Cetin, Alper 01 April 2007 (has links) (PDF)
In this thesis, design and implementation of a distribution-type, voltage source converter (VSC) based static synchronous compensator (D-STATCOM) having the simplest converter and coupling transformer topologies have been carried out. The VSC STATCOM is composed of a +/- 750 kVAr full-bridge VSC employing selective harmonic elimination technique, a low-pass input filter, and a &amp / #8710 / /Y connected coupling transformer for connection to medium voltage bus. The power stage of VSC based STATCOM is composed of water-cooled high voltage IGBT modules switched at 850 Hz for the elimination of 5th, 7th, 11th, 13th, 17th, 19th, 23rd,and 25th voltage harmonics. Special care has been taken in the laminated busbar design to minimize stray inductances between power semiconductors and dc link capacitor. Reactive power control is achieved by applying the phase angle control technique. The effect of input filter on total demand distortion has been investigated theoretically by mathematical derivations. The proposed VSC STATCOM has been implemented for reactive power compensation of Coal Preparation System in Kemerk&ouml / y Thermal Power Plant. The field test results have shown the success of the implemented system in view of fast response in reactive power compensation, and minimum input current harmonic content, and compliance with the IEEE Std. 519-1992 even for the weakest power systems. The application of selective harmonic elimination technique and phase angle control to VSC STATCOM has led to optimum switching frequency and device utilization for high voltage IGBTs at the expense of slower response as compared to other PWM techniques.
10

Vliv rozptýlené výroby na kvalitu elektrické energie / The effect of disperzed generation on power quality

Kružík, Martin January 2009 (has links)
This MASTER`S THESIS engages in connecting with dispersed generation into electrical network and their influence on power quality. This thesis sets out to make up simple dynamic model of Wind power station and model of simple network. At this model I would like to simulate influence its working on voltage’s characteristics in addition place. Besides this is necessary calculate voltage’s characteristics according present methods – factory energy rules [PNE]. And these results compare with results of simulation

Page generated in 0.0922 seconds