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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.
201

Statistical Analysis of Wind Data and Modeling Regulating Reserves

Buchanan, William 10 July 2012 (has links)
The desire to reduce dependence on fossil fuels is resulting in numerous policy incentives for increased renewable energy sources within the power grid. Because wind generation is arguably the most affordable per MWh of the renewable energy sources it is growing nearly as quickly as conventional generation techniques. Due to this significant increase in wind penetration levels, numerous largescale wind integration studies have been produced to determine the reliability impacts of large-scale wind power. Using data from two large US wind interconnection studies, this thesis provides evidence that mesoscale meteorological models under-predict the variability in wind data particularly on short time scales, indicating that data from mesoscale meteorological models need to be used with caution for some types of analyses. These types of analyses include most notably regulating reserves, which are used to rebalance supply and demand on a second-by-second bias. This thesis will also describe and evaluate a new method for jointly quantifying the amount of spinning and regulating reserves required to meet reliability requirements within a balancing area with significant amounts of wind power using high resolution wind data. The method is based on jointly minimizing dispatch costs and reserve allocations, across two time scales (seconds to minutes, and minutes to hours) to satisfy North American Electric Reliability Corporation (NERC) Area Control Error (ACE) requirements.
202

Wind-powered irrigation in Kansas : a system dynamics approach

Buck, Joel A January 2011 (has links)
Digitized by Kansas Correctional Industries
203

Die Leistung von AEOLUS II in Abhängigkeit von mittlerem Windprofil und Turbulenz im Bereich der Rotorfläche

Tetzlaff, Gerd, Hoppmann, Uwe 01 November 2016 (has links) (PDF)
Synchrone Messungen der Windgeschwindigkeit und die Leistung von Windkraftanlagen dienen der Ermittlung der Kennlinien der Anlagen. Die existierenden Vorschriften zur Vermessung enthalten bezüglich der Strömungseigenschaften des Windes nahezu keine Spezifikationen. Diese sind jedoch notwendig, um die erreichbare Genauigkeit und Repräsentativität der vermessenen Kennlinie zu quantifizieren. Messungen am Standort der AEOLUS II-Anlage in Wilhelmshaven dienten dazu, bei einer Anlagenvermessung die Eigenschaften der Strömung und die Kennlinie gemeinsam zu untersuchen. Es wurde gefunden, daß die Strömungseigenschaften wie die vertikale Windscherung, die Winddrehung über der Höhe, die turbulenten Schwankungen der Windgeschwindigkeit und der Windrichtung die Leistung von Windenergieanlagen bei gleicher mittlerer Windgeschwindigkeit erheblich verändern. Dabei wirken sowohl Standorteigenschaften als auch die Witterung auf die Ergebnisse der Vermessung. Am gleichen Standort können in anisotropem Gelände die Werte der Kennlinie auch bei mehrmonatigen Vermessungen wegen der Variabilität der Windrichtung Unterschiede von mehr als 10 % aufweisen. Der größte Einzeleffekt wird von der vertikalen Windscherung verursacht, die Wirkung der Drehung des mittleren Windvektors über der Rotorfläche ergab sich als kleinerer Effekt. Die Wirkung der turbulenten Schwankungen von Geschwindigkeit und Richtung weisen meist unterschiedliche Vorzeichen auf, so daß die Rolle dieser Schwankungen insgesamt meist klein bleibt. Die Vermessung einer Kennlinie mit einer kleineren systematischen Abweichung von im Mittel weniger als etwa 5 bis 10 % erfordert eine genaue Strömungsspezifikation sowohl für den Vermessungs- als für den Betriebsstandort, die bisher nicht in hinreichendem Maße in den entsprechenden Richtlinien und Vorschriften enthalten sind. / Power curves ofwind energy convetras need synchronous measurements of wind and power. The existing specification on the wind measurements are rather poor, however necessary. AEOLUS II-measurments and the wind measurments served to quantify the role of the different atmospheric parameters. Thus it was possible to define the influence on the power output of the machine as a function of the vertical wind shear, the wind veer with height, the turbulent fluctuations with the average wind speed being constant. As a consequence site properties and weather conditions both influence the measurements of the power curve. As a major result it was found that these factors may alter the power curve by as much as 10 %. The largest single effect is produced the effects of the vertical wind shear, The turbulent fluctuations are somewhat smaller in their effect, because speed and direction effects tend to compensate each other. lt may be concluded that a highly accurate power curve - meaning errors to be less than 10 % - requires a fully specified set of weather and site parameters.
204

Domestic demand response to increase the value of wind power

Hamidi, Vandad January 2009 (has links)
This thesis describes a new method to evaluate the value of wind power combined with domestic demand response. The thesis gives a brief overview of current domestic demand management programmes, and highlights the demand response and its current application. Such technology has conventionally been used for different purposes, such as frequency regulation, and to minimize the spot electricity prices in the market. The aim is to show whether such technology may become useful to make the renewables, and in particular wind power more interesting for investors. An assessment framework based on generation scheduling is developed to quantify the value of wind power. A further important aspect of value of wind power is the impact of intermittency on overall reliability of the system. This necessitates increasing the spinning reserve level which will increase the production cost. The changes in the spinning reserve level has been investigated in this thesis and it has been shown that how different forecasting errors may change the overall value of a windfarm over its lifetime. One of the most important aspects of a system containing demand response, is the availability of demand response. A load modelling package is developed to show the potential for demand response in a real system from domestic sector. With every increasing the concerns with regard to future of generation mix in Britain, this work has proposed over 72 scenarios for the future of generation mix in Britain and the impact of demand response to increase the value of wind power in 2020 has been investigated. The assessment framework is enhanced by showing that how the value of wind power combined with domestic demand response may change by changes in emission price, and cost of demand response. This will show the degree of feasibility of such system in which demand response is treated like a commodity.
205

The value of electrical energy storage : a comparison between commercial and system level benefits

Dunbar, Anna January 2016 (has links)
There is a drive to transform the electricity industry in the UK from one based largely on fossil fuels to one based on low or zero carbon sources. The challenge of this transition, enabling a secure and sustainable electricity industry at an acceptable cost to consumers, has been dubbed the Energy Trilemma. Grid-connected electrical energy storage presents a potential solution to this challenge. However, the benefits of storage are split across different sectors of the electricity industry and there are a number of regulatory barriers preventing access to revenue streams. One accessible revenue stream is energy trading or price arbitrage. In current market conditions, arbitrage cannot provide sufficient revenue for electricity storage to cover its capital costs; however, some studies have suggested that with increased penetration of intermittent renewable power, electricity price volatility will increase enabling storage to become commercially viable through price arbitrage alone. This thesis examines the hypothesis that: Increased wind penetration leads to increased commercial opportunities for energy storage through price arbitrage. A linear programme is used to define the optimum operating strategy for a storage device, subject to the constraints of maximum storage capacity, charging and discharging rates, conversion efficiency and self-discharge. Initially, historic electricity prices from the British electricity market are used to investigate the value of storage with a low penetration of intermittent wind power. The results show that revenue is dependent on storage characteristics, with the performance of different technologies varying substantially. Furthermore, revenue is highly dependent on changes in market structure and fuel price variations from one year to the next. The thesis describes the development of a fundamental electricity price model based on the stacked merit order dispatch of thermal generation bidding to produce electricity in a competitive market centred around marginal generation costs. For peaking plant, an exponential uplift in price is applied to represent scarcity of supply. The implications of increasing wind power output are examined using projections of the location and capacity of future wind farms and spatially distributed hind cast wind speed data generated from a mesoscale atmospheric model. The analysis highlights that despite increased value being placed on storage in an energy system with a high penetration of wind power, opportunities for arbitrage are, in fact, reduced. This is a result of an oversupply of electricity on windy days suppressing peak electricity prices and reducing the daily price spread, which arbitrage exploits.
206

Control of a variable-shaftspeed electromechanical energy-conversion system.

Simkovits, Harvey Roy January 1976 (has links)
Thesis. 1976. B.S.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / Microfiche copy available in Archives and Engineering. / Includes bibliographical references. / B.S.
207

Análise da integração de usinas eólicas através dos requisitos técnicos dos procedimentos de rede do ONS /

Caldas, Danilo Monteiro. January 2019 (has links)
Orientador: Flavio Alessandro Serrão Gonçalves / Coorientador: Helmo Kelis Morales Paredes / Banca: Fernando Pinhabel Marafao / Banca: Juan Carlos Cebrian Amasifen / Resumo: Este trabalho realiza uma análise dos principais temas sobre qualidade de energia de usinas eólicas através de uma revisão bibliográfica das principais normas nacionais e internacionais, dando ênfase aos Procedimentos de Rede do ONS (Operador Nacional do Sistema Elétrico). São avaliados os aspectos técnicos relativos à conexão elétrica de uma usina eólica ao Sistema Interligado Nacional brasileiro (SIN), propondo uma sequência de análises para integrar uma metodologia de verificação do cumprimento de novos requisitos do Submódulo 3.6 dos Procedimentos de Rede utilizando os pacotes de softwares de análise de rede do CEPEL (ANAREDE, ANATEM e HarmZs). Foram revisadas, nesta nova versão publicada em dezembro de 2016, as exigências relativas à capacidade de potência reativa, controle de tensão, impacto na qualidade de energia e funcionamento durante distúrbios de tensão e frequência (Fault Ride Through, Inércia Sintética e controle P(f)). Para cada um dos requisitos são apresentados exemplos de aplicação da metodologia proposta através de estudos de caso, considerando um aerogerador do tipo Full-Converter e através dos resultados destes estudos demonstra-se que a metodologia proposta permite a verificação dos principais requisitos dos Procedimentos de Rede na fase de planejamento da usina eólica, dando previsibilidade e segurança tanto para o desenvolvedor do projeto, quanto ao ONS. O conjunto das orientações e procedimentos propostos, pela primeira vez apresentado de forma integr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work presents an assessment of the main topics related to power quality on wind power plants through a bibliographical review of the main national and international standards, with emphasis on the Procedimentos de Rede from ONS (Operador Nacional do Sistema Elétrico) . The technical aspects related to a wind farm grid connection to the Brazilian National Interconnected System (Sistema Interligado Nacional - SIN) are evaluated, proposing a sequence of analyses to integrate a methodology in order to verify the compliance with the new requirements from the Sub-module3.6 of the Procedimentos de Rede using the grid analysis software packages from CEPEL (ANAREDE, ANATEM and HarmZs). The requirements for reactive power capability, voltage control, power quality impact and operation during voltage and frequency disturbances (Fault Ride Through, Systhetic Inertia, and P(f) control) were reviewed in this new version published in December 2016. Examples for the application of the methodology proposed are presented for each of the requirements through case studies considering a Full-Converter type wind turbine and through the results of these studies it is demonstrated that the proposed methodology allows the verification of the main requirements of the Procedimentos de Rede in the planning phase of the wind farm, giving predictability and safety for both the project developer and ONS. The set of proposed guidelines and procedures, for the first time entirely presented in a single t... (Complete abstract click electronic access below) / Mestre
208

Control method for renewable energy generators

Aljaism, Wadah A., University of Western Sydney, School of Engineering and Industrial Design January 2002 (has links)
This thesis presents a study on the design method to optimise the performance for producing green power from multiple renewable energy generators. The design method is presented through PLC (Programmable Logic Controller) theory. All the digital and analogue inputs are connected to the input cards. According to different operations conditions for each generator, the PLC will image all the inputs and outputs, from these images; a software program has been built to create a control method for multiple renewable energy generators to optimise production of green power. A control voltage will supply the output contractor from each generator via an interface relay. Three renewable generators (wind, solar, battery bank) have been used in the model system and the fourth generator is the back up diesel generator. The priority is for the wind generator due to availability of wind 24 hours a day, then solar, battery bank, and LPG or Diesel generators. Interlocking between the operations of the four contractors has been built to prevent interface between them. Change over between contractors, according to the generator's change over has also been built, so that it will delay supplying the main bus bar to prevent sudden supply to the load. Further study for controlling multiple renewable energy generators for different conditions such as controlling the multi-renewable energy generators from remote, or supplying weather forecast data from bureau of meteorology to the PLC directly as recommended. / Master of Electrical Engineering (Hons)
209

Characterising the uncertainty in potential large rapid changes in wind power generation

Cutler, Nicholas Jeffrey, Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW January 2009 (has links)
Wind energy forecasting can facilitate wind energy integration into a power system. In particular, the management of power system security would benefit from forecast information on plausible large, rapid change in wind power generation. Numerical Weather Prediction (NWP) systems are presently the best available tools for wind energy forecasting for projection times between 3 and 48 hours. In this thesis, the types of weather phenomena that cause large, rapid changes in wind power in southeast Australia are classified using observations from three wind farms. The results show that the majority of events are due to horizontal propagation of spatial weather features. A study of NWP systems reveals that they are generally good at forecasting the broad large-scale weather phenomena but may misplace their location relative to the physical world. Errors may result from developing single time-series forecasts from a single NWP grid point, or from a single interpolation of proximate grid points. This thesis presents a new approach that displays NWP wind forecast information from a field of multiple grid points around the wind farm location. Displaying the NWP wind speeds at the multiple grid points directly would potentially be misleading as they each reflect the estimated local surface roughness and terrain at a particular grid point. Thus, a methodology was developed to convert the NWP wind speeds at the multiple grid points to values that reflect surface conditions at the wind farm site. The conversion method is evaluated with encouraging results by visual inspection and by comparing with an NWP ensemble. The multiple grid point information can also be used to improve downscaling results by filtering out data where there is a large chance of a discrepancy between an NWP time-series forecast and observations. The converted wind speeds at multiple grid points can be downscaled to site-equivalent wind speeds and transformed to wind farm power assuming unconstrained wind farm operation at one or more wind farm sites. This provides a visual decision support tool that can help a forecast user assess the possibility of large, rapid changes in wind power from one or more wind farms.
210

Fostering technologies for sustainability: Improving Strategic Niche Management as a guide for action using a case study of wind power in Australia

Healey, Gerard Patrick, Gerard.healey@arup.com.au January 2008 (has links)
Society is making increasing efforts to become more sustainable by fostering new technologies such as renewable energy. Often, there are significant challenges to introducing new technologies because existing infrastructure, institutions, social groupings, and behaviours have co-evolved with and consequently support incumbent technologies - a condition known as lock-in. To support efforts to introduce new technologies, researchers have developed conceptual frameworks that aim to increase our understanding of socio-technical change. One promising framework is Strategic Niche Management (SNM); however despite its strength as an ex post analytical tool, SNM has yet to be used to guide experiments with new technologies. This thesis aims to make SNM more usable for those introducing new technologies by responding to four weaknesses identified in existing literature: a weak link between the conceptual framework and action, the vague role of actors, an inadequate appreciation of issues of consensus and limits of influence, and an inadequate appreciation of the challenges that actors may face. This is achieved by identifying promising insights and testing them on a case study of wind power in Australia. The literature review identifies dynamics that have been linked to positive feedbacks in the development of new technologies and socio-technical change. These are: stimulating demand, increasing use, learning and articulation, increasing functionality, decreasing costs, decreasing uncertainty, embedding and alignment, increasing legitimacy, attracting actors, and strengthening expectations and visions. These dynamics can be used to provide a better link between theory and action. The review also identifies particular actor roles - such as niche manager, macro actor, prime mover, and dedicated network builder - and actions that actors in these roles may take. These roles and actions are linked to the dynamics. Also reviewed are issues related to consensus and limits of influence; a particularly useful concept in this regard is resource interdependency. Finally, the review identifies challenges to encouraging the dynamics aimed at helping actors to anticipate problems in the introduction of new technologies. T he relevance of this approach and applicability of these insights are tested with a case study of wind power in Australia. The case study explains changes related to grid-connected wind power in Australia between about 1997 and 2007. There was significant socio-technical change: for example, installed grid-connected wind farm capacity grew from about 1 MW to almost 900 MW, an industry and industry association formed, there were unprecedented changes in energy policy, new high-level actor groups formed to oversee the grid-integration of wind power, Governments amended planning schemes, and public opinion was increasingly articulated. The dynamics identified in the literature review were all relevant to wind power. The study provides examples of the actors that can encourage these dynamics and how they might do so. Most challenges identified in the literature review were relevant to wind power and possible strategies for managing them were identified. Also revealed were challenges in transitional strategies, legitimacy of the technology and consensus. These findings are discussed in detail. These findings are intended to help actors foster technologies for sustainability.

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