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  • 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

Zukünftige Belastungen von Niederspannungsnetzen unter besonderer Berücksichtigung der Elektromobilität / Future Loads of low-voltage grids with a special attention to electric mobility

Götz, Andreas 27 April 2016 (has links) (PDF)
Aktuell finden umfangreiche Neuerungen und Veränderungen im Elektroenergiesystem statt. Dabei stellen die Netzintegration von Energiespeichern, EE-Anlagen und Elektrofahrzeugen sowie die Realisierung von Energiemanagementsystemen wichtige Neuerungen in der Niederspannungsebene dar. Analysen der Ladevorgänge von Elektrofahrzeugen zeigen einen nennenswerten Einfluss auf den Lastbedarf. Als ein Ergebnis wird die maximal zulässige Anzahl an Elektrofahrzeugen ermittelt, bei der kein Netzumbau notwendig wird. Neben der Untersuchung verschiedener Ladevarianten wird die zufällige Ladung als innovative Ladevariante vorgestellt und deren Nutzen simuliert. / Currently, fundamental innovations and changes are occurring in the power system. The grid integration of energy storage systems, renewable energy systems and electric vehicles as well as the implementation of energy management systems are important innovations in the low-voltage grid. Analyses of charging processes for electric vehicles show significant impacts on the load demand. As one result, the maximum number of electric vehicles is determined assuming that no grid expansion is needed. Besides studying various charging options, a random charging method is proposed as an innovative charging option and its benefits are shown by simulations.
2

Ações de conservação de energia aplicadas a uma planta industrial composta de motores de indução / Action of conservation of energy applied to one plants composed industrial of induction motors

Facco, José Henrique 31 March 2006 (has links)
O presente trabalho objetiva, a partir de dados coletados dos motores elétricos em regime de trabalho, dar sua contribuição ao estudo de conservação de energia elétrica numa planta industrial. Apresenta-se o motor elétrico trifásico de indução e as diversas questões relativas ao seu uso industrial, para então, demonstrarem os parâmetros elétricos obtidos. Elaborou-se um trabalho de campo, que possibilita à análise da eficiência energética no uso de motores elétricos em uma fábrica de papel e cosméticos. A partir de medidas dos parâmetros elétricos como: corrente e tensão, mais os dados de catálogos do fabricante, chegaram-se aos valores de rendimento, fator de potência e fator de utilização, para diversas condições de carga dos motores. Caso o fator de utilização seja inferior a 75%, um estudo comparativo permitirá as decisões de substituição dos motores super dimensionados. Os dados são usados para as seguintes análises: qual a possível conservação de energia elétrica para cada setor, se os motores fossem substituídos por unidades de alto rendimento?; qual a viabilidade de cada setor realizar as trocas imediatas por motores de alto rendimento?; qual à economia de energia elétrica por setores em (R$/dia), utilizando motores de alto rendimento?; em quanto tempo obteríamos o retorno desse investimento? Alguns recursos de informática foram utilizados nos cálculos realizados. Os resultados indicam que o potencial de conservação de energia elétrica em motores deve ser melhor explorado e de forma mais consciente. / The objective of the present research, from a data set of electric motor collected in a regimen of work, give its contribution to the study on industrial electrical motors’ energy saving. It present the three-phase induction motor, the various issues of its industrial use and the electric parameter set collected are then presented. Field of work was elaborated, wich allowed the analysis of the energy efficiency in the use of electric engines in industry of paper and cosmetics. Given the measurements of current and tension, plus the data from the manufacter’s catalogs, values of efficiency were obtained, power factor and utilization factor, for diverse conditions of engine load. But in case the utilization factor is less than 75%, a comparative study allowed the decisions of substitution of the poorly dimensioned engines. The data are analyzed in ways: 1)What would be the energy save to each sector, if motors were changed for high efficient units? 2)What would be the viable to each sector to replace immediately the existing motors for high efficient? 3)What would be the energy save to each sector in (R$/day), using high efficient motors? 4)How much time would be the return of the investiment?. Some resources of computer technology were used in the calculations. The results showing the electric energy saving potential in motor would be better use to advantage and more conscientions form.
3

Ações de conservação de energia aplicadas a uma planta industrial composta de motores de indução / Action of conservation of energy applied to one plants composed industrial of induction motors

José Henrique Facco 31 March 2006 (has links)
O presente trabalho objetiva, a partir de dados coletados dos motores elétricos em regime de trabalho, dar sua contribuição ao estudo de conservação de energia elétrica numa planta industrial. Apresenta-se o motor elétrico trifásico de indução e as diversas questões relativas ao seu uso industrial, para então, demonstrarem os parâmetros elétricos obtidos. Elaborou-se um trabalho de campo, que possibilita à análise da eficiência energética no uso de motores elétricos em uma fábrica de papel e cosméticos. A partir de medidas dos parâmetros elétricos como: corrente e tensão, mais os dados de catálogos do fabricante, chegaram-se aos valores de rendimento, fator de potência e fator de utilização, para diversas condições de carga dos motores. Caso o fator de utilização seja inferior a 75%, um estudo comparativo permitirá as decisões de substituição dos motores super dimensionados. Os dados são usados para as seguintes análises: qual a possível conservação de energia elétrica para cada setor, se os motores fossem substituídos por unidades de alto rendimento?; qual a viabilidade de cada setor realizar as trocas imediatas por motores de alto rendimento?; qual à economia de energia elétrica por setores em (R$/dia), utilizando motores de alto rendimento?; em quanto tempo obteríamos o retorno desse investimento? Alguns recursos de informática foram utilizados nos cálculos realizados. Os resultados indicam que o potencial de conservação de energia elétrica em motores deve ser melhor explorado e de forma mais consciente. / The objective of the present research, from a data set of electric motor collected in a regimen of work, give its contribution to the study on industrial electrical motors’ energy saving. It present the three-phase induction motor, the various issues of its industrial use and the electric parameter set collected are then presented. Field of work was elaborated, wich allowed the analysis of the energy efficiency in the use of electric engines in industry of paper and cosmetics. Given the measurements of current and tension, plus the data from the manufacter’s catalogs, values of efficiency were obtained, power factor and utilization factor, for diverse conditions of engine load. But in case the utilization factor is less than 75%, a comparative study allowed the decisions of substitution of the poorly dimensioned engines. The data are analyzed in ways: 1)What would be the energy save to each sector, if motors were changed for high efficient units? 2)What would be the viable to each sector to replace immediately the existing motors for high efficient? 3)What would be the energy save to each sector in (R$/day), using high efficient motors? 4)How much time would be the return of the investiment?. Some resources of computer technology were used in the calculations. The results showing the electric energy saving potential in motor would be better use to advantage and more conscientions form.
4

Optimalizace tvaru háků v pecích petrochemického průmyslu / Optimalization of hanger design in petrochemical industry

Horsák, Libor January 2010 (has links)
Master’s thesis, „Optimization of hanger design in petrochemical industry heaters”, describes a procedure and means, leading to better hanger design in various cases. The thesis describes several problems which are necessary to be solved in hanger design. Technical expertise is executed on hangers of various designs. The procedure of optimization is shown on one chosen hanger design.
5

Evaluating the Efficient Grid Utilisation Incentive : Through the design of the load flow indicator

Ndayisaba, Chris-Antony, Sammils, Isabelle January 2023 (has links)
The Swedish energy markets inspectorate (Ei) regulates the Swedish DSOs revenue cap, to ensure reasonable prices, efficiency, and quality of supply towards the end users. In combination with directives from the European Union and Sweden's environmental goal, Ei implemented efficient grid utilization to the DSOs revenue cap in 2016. The efficient grid utilization can be divided into two incentives: load flow and network losses. Criticism regarding the load flow incentive, and the indicator used to calculate it, has been raised from the industry. The purpose of this degree project was to investigate the possibilities of a new indicator that also could be affected by the DSOs actions. The project identified four main indicators to test, weighted load factor, utilization factor, adjusted utilization factor and a utilization factor that incorporates all local production units. The indicators were calculated with data from a regional and local grid, provided by the Swedish DSO Ellevio. Other parameter changes such as peaks and seasonal based calculations were also tested. To see the impact DSOs could have on the indicator, with today's regulations, was detected to be through load shaving and shifting, demand side management (DSM). MATLAB was used to test the impact DSM had on the indicators. Further, a load prediction for the years 2023–2035, based on provided historical data, was executed to test the indicators long-term outcome. The project concluded that the regional grid had little to non-impact on the indicators with DSM whilst the local grid resulted in high increased outcome for most indicators. The project continues to conclude to separate indicators for the regional and local grid, to better represent the two grids characteristic and purpose in Swedish society. The adjusted utilization factor was proposed for the regional grid, due to its non-negative impact from installing renewable energy resources, and the weighted load factor for the local grid due to being highly affected by DSM. Lastly, the project concluded that the indicator needs to be changed and further developed for regional DSOs, for them to have the opportunity to affect it.
6

A Stochastic Analysis Framework for Real-Time Systems under Preemptive Priority-Driven Scheduling

Azhar, Muhammad January 2011 (has links)
This thesis work describes how to apply the stochastic analysis framework, presented in [1] for general priority-driven periodic real-time systems. The proposed framework is applicable to compute the response time distribution, the worst-case response time, and the deadline miss probability of the task under analysis in the fixed-priority driven scheduling system. To be specific, we modeled the task execution time by using the beta distribution. Moreover, we have evaluated the existing stochastic framework on a wide range of periodic systems with the help of defined evaluation parameters. In addition we have refined the notations used in system model and also developed new mathematics in order to facilitate the understanding with the concept. We have also introduced new concepts to obtain and validate the exact probabilistic task response time distribution.    Another contribution of this thesis is that we have extended the existing system model in order to deal with stochastic release time of a job. Moreover, a new algorithm is developed and validated using our extended framework where the stochastic dependencies exist due to stochastic release time patterns. / This is Second Version of the report. Submitted after few modifications made on the order of Thomas Nolte (Thesis Examiner). / START - Stochastic Real-Time Analysis of Embedded Software Systems
7

Alternativní zdroje energie a jejich integrace do konceptu Smart Grids / Alternative Energy Sources and Their Integration into the Concept of Smart Grids

Kopička, Marek January 2012 (has links)
This work deals mainly with electrical energy. In the first part is focused on alternative energy sources, and describes structure of consumption and production of electricity over the past few years, during which is focuses on renewable energy sources. In this context, assesses the conditions for alternative energy sources in the Czech Republic from the perspective of the legislative, as well as current status and potential of alternative energy sources and tries to predict the development of these issues. The next section describes the Smart Grids as a means to achieve these goals. There are presented the basic features of this system, its goals and challenges, a description of the integration of Smart Grids with other sources of electricity and the benefits of using Smart Grids both from the perspective of user and from the perspective of system. Other parts are focused on distributed control systems in the energy sector, its development and principle. The last part is devoted to consideration of the role of alternative energy sources and distributed generation in Smart Grids.
8

Zukünftige Belastungen von Niederspannungsnetzen unter besonderer Berücksichtigung der Elektromobilität

Götz, Andreas 02 February 2016 (has links)
Aktuell finden umfangreiche Neuerungen und Veränderungen im Elektroenergiesystem statt. Dabei stellen die Netzintegration von Energiespeichern, EE-Anlagen und Elektrofahrzeugen sowie die Realisierung von Energiemanagementsystemen wichtige Neuerungen in der Niederspannungsebene dar. Analysen der Ladevorgänge von Elektrofahrzeugen zeigen einen nennenswerten Einfluss auf den Lastbedarf. Als ein Ergebnis wird die maximal zulässige Anzahl an Elektrofahrzeugen ermittelt, bei der kein Netzumbau notwendig wird. Neben der Untersuchung verschiedener Ladevarianten wird die zufällige Ladung als innovative Ladevariante vorgestellt und deren Nutzen simuliert. / Currently, fundamental innovations and changes are occurring in the power system. The grid integration of energy storage systems, renewable energy systems and electric vehicles as well as the implementation of energy management systems are important innovations in the low-voltage grid. Analyses of charging processes for electric vehicles show significant impacts on the load demand. As one result, the maximum number of electric vehicles is determined assuming that no grid expansion is needed. Besides studying various charging options, a random charging method is proposed as an innovative charging option and its benefits are shown by simulations.

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