Dissertations / Theses: 'Power and load factor'

1

Meng, Tianyu. "Study on Plant Load Factor of Wind Power CDM Projects." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-204402.

Full text

Abstract:

Clean Development Mechanism (CDM), is a market-based mechanism under the Kyoto Protocol. It allows developed countries to implement emission reduction projects in developing countries, to assist their sustainable development; meanwhile, developed countries gain credits which could be used to meet part of their emission reduction targets under this protocol. There is a wide range of various types of CDM projects, among which, wind power projects account for the largest share. Additionality is a key component for CDM projects’ eligibility and to ensure CDM’s environmental integrity. It means that the emission reduction after the implementation of the project is additional to any that would have occurred in the absence of the certified CDM project. For wind CDM projects, the controversy on additionality raised debate and attention internationally, especially the concern if project developers deliberately underestimated Plant Load Factor (PLF) so as to meet the CDM additionality criterion. At the United Nations Framework Convention on Climate Change (UNFCCC) CDM Executive Board 63rd meeting, the UNFCCC Secretariat and the Registration and Issuance Team (RIT) proposed different decisions regarding a request forissuance of a Wind CDM project due to different views on the estimated PLF. The Board discussed the issue andrequested a study on the PLF variations, which is the origin, and also a partial content of this thesis.In this thesis, relevant parameters are firstly defined – parameters such as Estimated PLF, Actual PLF, etc, and to better illustrate the magnitude of the PLF variation, the concept of Relative Variation of PLF is adopted, which is measured as the absolute difference of Estimated PLF and Actual PLF compared with Estimated PLF. Then a database in spreadsheet with all defined parameters of sampled projects is set up on the basis of collected information and calculation. Afterwards an investigation of PLFs and comparison analyses of Estimated PLFs and Actual PFLs is conducted. Considering there are two groups of Wind CDM projects, i.e. small-scale and large-scale; and considering the distributions of projects’ hosting countries, the comparison analyses are then conducted firstly for all projects, and then separated for small-scale and large-scale projects, and lastly separated for projects based on different hosting countries. The final results show that a minority of projects have underestimated PLFs, and a very small proportion of projects, either in all projects, or on different scales or in different hosting countries have underestimated PLFs to a level that is out of acceptable range. Therefore, thestudy concludes that there should be no concern on the PLF issue in Wind CDM projects.

APA, Harvard, Vancouver, ISO, and other styles

2

Ruckdaschel, James David. "Harmonic Analysis of a Static VAR Compensated Mixed Load System." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/82.

Full text

Abstract:

As power electronic based controllers and loads become more prevalent in power systems, there is a growing concern about how the harmonics generated by these controllers and loads affect the power quality of the system. One widely used power electronic based load is the Variable Frequency Drive (VFDs) used to vary the speed of an induction motor; whereas a common example of a power electronic based controller used in power systems is the Static VAR Compensator (SVC) for improving a system’s power factor. In this thesis, the harmonic content and overall performance of a system including both a VFD and a SVC will be studied and analyzed. Specifically, the cases of no compensation, static capacitor compensation, and power electronic based static VAR compensation are examined. A small-scale model of a system for study was constructed in lab. Several cases were then performed and tested to simulate a system which contained both fixed and power electronic based harmonic generating loads. The performance of each case was determined by total harmonic current and voltage distortions, true power factor, and RMS current levels at different points in the system.

APA, Harvard, Vancouver, ISO, and other styles

3

Moynahan, Nathan A. "Development of a vehicle road load model for ECU broadcast power verification in on-road emissions testing." Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4454.

Full text

Abstract:

Thesis (M.S.)--West Virginia University, 2005.
Title from document title page. Document formatted into pages; contains xi, 117 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 75-77).

APA, Harvard, Vancouver, ISO, and other styles

4

Struthers, Christopher Andrew. "Three phase load balancing and power factor correction using a pulse width modulated static compensator." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62855.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Guelfi, Rangel [UNESP]. "Análise da relação entre o faturamento do consumo de energia elétrica e demanda de potência ativa e reativa utilizando hiperbolóides de carga e potência." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/87214.

Full text

Abstract:

Made available in DSpace on 2014-06-11T19:22:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-05-31Bitstream added on 2014-06-13T20:09:50Z : No. of bitstreams: 1 guelfi_r_me_ilha.pdf: 667745 bytes, checksum: 4cf02e10ba92af5e81fd3f18fda6f6cd (MD5)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
No presente trabalho é apresentado um método para o cálculo de volumes determinados por K-Hiperbolóides de Carga e Potência, de modo a reduzir os gastos de empresas consideradas, em relação ao fator de potência. A redução de gastos é obtida alterando-se o valor máximo do fator potência que se pretende chegar, do fator de potência ideal 1, para o fator de potência de referência 0,92, ou mantendo-o quando já estiver acima de 0,92. Quando o fator de potência é maior ou igual a 0,92 ele já está eficiente, assim, não há necessidade de se chegar ao fator de potência ideal. É realizada uma comparação entre um método existente na literatura e o método proposto no presente trabalho, para determinar os pontos em que estes métodos diferem no cálculo dos volumes determinados pelos K-Hiperbolóides de Carga e Potência e mostrar a eficácia do método proposto. Estes métodos são equiparados, com relação a redução obtida no faturamento da conta de energia elétrica. A redução no faturamento da conta de energia elétrica que deve ser pago à concessionária é obtida por meio da diminuição da demanda contratada pela empresa; por sua vez a diminuição desta demanda é alcançada através da fórmula do fator de carga. Considerando-se a demanda média e o maior fator de carga obtido no período em estudo, encontra-se assim, uma nova demanda máxima menor que a demanda atual utilizada pela empresa. Logo, esta demanda máxima passa a ser a demanda que será contratada pela empresa, assim, esta nova demanda resulta em uma nova fatura que deve ser paga a concessionária de energia elétrica, menor que a fatura atual.
The present work presents a method for the calculation of volumes determined for K- Load and Power Hyperboloid, in order to reduce the expenses of considered companies, in relation to the power factor. The reduction of expenses is gotten by changing the maximum value of the wished power factor, of the ideal power factor1, to the reference power factor 0,92,or keeping it when it s above 0,92. When the power factor is higher or equal 0,92, it s already efficient, thus, it is not necessary to achieve the ideal power factor. A comparison is carried between an existing method in the literature and the considered method in the present work, to determine the points where these methods differ from each other in the calculation of the volumes determined for the K-Load and Power Hyperboloid and to show the effectiveness of the considered method. These methods are equalized, regarding the reduction gotten in the invoicing of the electric energy account. The reduction in the invoicing of the account of electric energy that must be paid to the concessionaire is gotten through the reduction of the contracted demand by the company; in turn the reduction of this demand is reached through the formula of the load factor. Considering the average demand and the highest load factor gotten in the period in study, this way a new demand, lower than the current demand used by the company, is gotten. Therefore, this maximum demand starts to be the demand that will be contracted by the company, thus, this new demand results in a new invoice which must be paid to the concessionaire of electric energy, lower than the current invoice.

APA, Harvard, Vancouver, ISO, and other styles

6

Guelfi, Rangel. "Análise da relação entre o faturamento do consumo de energia elétrica e demanda de potência ativa e reativa utilizando hiperbolóides de carga e potência /." Ilha Solteira : [s.n.], 2007. http://hdl.handle.net/11449/87214.

Full text

Abstract:

Resumo: No presente trabalho é apresentado um método para o cálculo de volumes determinados por K-Hiperbolóides de Carga e Potência, de modo a reduzir os gastos de empresas consideradas, em relação ao fator de potência. A redução de gastos é obtida alterando-se o valor máximo do fator potência que se pretende chegar, do fator de potência ideal "1", para o fator de potência de referência "0,92", ou mantendo-o quando já estiver acima de 0,92. Quando o fator de potência é maior ou igual a 0,92 ele já está eficiente, assim, não há necessidade de se chegar ao fator de potência ideal. É realizada uma comparação entre um método existente na literatura e o método proposto no presente trabalho, para determinar os pontos em que estes métodos diferem no cálculo dos volumes determinados pelos K-Hiperbolóides de Carga e Potência e mostrar a eficácia do método proposto. Estes métodos são equiparados, com relação a redução obtida no faturamento da conta de energia elétrica. A redução no faturamento da conta de energia elétrica que deve ser pago à concessionária é obtida por meio da diminuição da demanda contratada pela empresa; por sua vez a diminuição desta demanda é alcançada através da fórmula do fator de carga. Considerando-se a demanda média e o maior fator de carga obtido no período em estudo, encontra-se assim, uma nova demanda máxima menor que a demanda atual utilizada pela empresa. Logo, esta demanda máxima passa a ser a demanda que será contratada pela empresa, assim, esta nova demanda resulta em uma nova fatura que deve ser paga a concessionária de energia elétrica, menor que a fatura atual.
Abstract: The present work presents a method for the calculation of volumes determined for K- Load and Power Hyperboloid, in order to reduce the expenses of considered companies, in relation to the power factor. The reduction of expenses is gotten by changing the maximum value of the wished power factor, of the ideal power factor"1", to the reference power factor "0,92",or keeping it when its above 0,92. When the power factor is higher or equal 0,92, its already efficient, thus, it is not necessary to achieve the ideal power factor. A comparison is carried between an existing method in the literature and the considered method in the present work, to determine the points where these methods differ from each other in the calculation of the volumes determined for the K-Load and Power Hyperboloid and to show the effectiveness of the considered method. These methods are equalized, regarding the reduction gotten in the invoicing of the electric energy account. The reduction in the invoicing of the account of electric energy that must be paid to the concessionaire is gotten through the reduction of the contracted demand by the company; in turn the reduction of this demand is reached through the formula of the load factor. Considering the average demand and the highest load factor gotten in the period in study, this way a new demand, lower than the current demand used by the company, is gotten. Therefore, this maximum demand starts to be the demand that will be contracted by the company, thus, this new demand results in a new invoice which must be paid to the concessionaire of electric energy, lower than the current invoice.
Orientador: Francisco Villarreal Alvarado
Coorientador: Antonio Padilha Feltrin
Banca: Sérgio Azevedo de Oliveira
Banca: Iara Fernanda Ehrenberg Dossi Denis
Mestre

APA, Harvard, Vancouver, ISO, and other styles

7

Wang, Ran. "Market power, cost efficiency and pricing strategies of domestic airline industry." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53930.

Full text

Abstract:

This dissertation first develops a theoretical framework to enable the estimation of cost efficiency and conduct parameter without total cost data. By validating this framework using U.S. airline data, this dissertation shows the feasibility of the theoretical framework. Based on the estimates of marginal cost efficiency and conduct parameter, this dissertation also finds some support for the Quiet Life Hypothesis. In Chapter III, this dissertation analyzes the determinants for price dispersion, especially conduct parameter and cost efficiency. Generally speaking, we find negative relationship between conduct parameter and price dispersion and negative relationship between marginal cost efficiency and price dispersion. In Chapter IV, this thesis examines the dynamics that lead to high price dispersion. To be more specific, this thesis concentrates on advanced days purchased and load factor.

APA, Harvard, Vancouver, ISO, and other styles

8

Pierce, Timothy M. Jr. "Mobile Hybrid Power System Theory of Operation." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/78148.

Full text

Abstract:

Efficiency is a driving constraint for electrical power systems as global energy demands are ever increasing. Followed by the introduction of diesel generators, electricity has become available in more locations than ever. However, operating a diesel generator on its own is not the most energy efficient. This is because the high crest factor loads, of many applications, decrease the fuel efficiency of a hydrocarbon generator. To understand this, we need to understand how an electrical load affects a generator. Starting with a load profile, a system designer must choose a generator to meet peak demand, marking the first instance where a load profile has influence over a generator. This decision will insure that brownouts do not occur, but, this will lead to poor energy efficiency. We say this because a generator is most energy efficient under heavier loads, meaning, during lighter loads, more fuel will be consumed to produce the same amount of energy. While this may be fine if the peak load was close to the average load, however, the actual crest factor for a typical residential load profile is much higher. This gap between peak and average load means that a generator will spend most of its time operating at its most inefficient point. To compensate for this, and reduce fuel consumption, the Mechatronics Lab at Virginia Tech has developed a mobile hybrid power system (MHPS) to address this problem. The solution was to augment a diesel generator with a battery pack. This allowed us to constrain the generator so that it only operates with fixed efficiency. It is the theory behind this system that will be covered in this thesis.
Master of Science

APA, Harvard, Vancouver, ISO, and other styles

9

VIEIRA, FRANCISCO ANIZIO. "THERMO-ACCUMULATION: AN EFFECTIVE ALTERNATIVE FOR INCREASING THE POWER LOAD FACTOR IN ELECTRICITY RETAILING LEADING TO DIFFERENTIATED TARIFF BILLINGS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=32996@1.

Full text

Abstract:

Desenvolvida no âmbito da linha de pesquisa Metrologia para Energia, a presente dissertação de mestrado tem como objetivo validar os benefícios da tecnologia da termoacumulação como alternativa técnica e economicamente viável para deslocamento de cargas elétricas em períodos de grande utilização. O projeto de pesquisa teve como motivação o estudo de alternativas tecnológicas para viabilizar tarifas diferenciadas. A metodologia utilizada incluiu a revisão da literatura especializada sobre regulação tarifária e termoacumulação; desenvolveu estudos de sistemas de distribuição subterrâneos e aéreos situados em regiões de grande demanda de energia elétrica no horário comercial e desenvolveu análise de sensibilidade técnico-econômica visando a proposição de alternativas tarifárias e políticas de deslocamento de carga. O trabalho se desenvolveu no contexto da segunda revisão tarifária do setor elétrico, que busca repartir os ganhos de eficiência obtidos pelos agentes do setor elétrico com os seus consumidores. Dentre os resultados do trabalho destacam-se: (i) a comprovação da viabilidade da aplicação da termoacumulação em sistemas de climatização, (ii) a redução de custos de operação e implantação de subestações de energia elétrica para consumidores de sistemas de refrigeração e (iii) e proposição de uma tarifa diferenciada que permite a mudança do perfil de carga de sistemas de refrigeração comerciais. Estudos realizados mostraram que a termoacumulação pode gerar redução dos custos de energia elétrica da ordem de 30 a 45 por cento. Como conclusões, o trabalho reconhece a importância de se implantar políticas que privilegiem novas alternativas tarifárias e ressalta os benefícios que resultam da adoção dessa tecnologia alternativa para o meio ambiente.
Studies have shown that thermo-accumulation is an attractive technology to increase the electric power load factor which can lower tariff billings in electricity retailing (30-45 percent), the motivation for this research project. The aim of the present M.Sc. dissertation is to validate the technological benefits of thermo-accumulation applied to the electric sector as an economically feasible alternative for power load displacement at peak mode. The methodology included a literature survey on tariff billings and the regulation of the electric sector; a study of aerial and underground distribution systems at locations of high power load demand; a technical-economic analysis (consumption and tariff) of power substations. Developed within the context of tariff billing revision where the electric sector shared energy-efficient gains with customers, the research project suggests alternate tariff schemes and power load displacement policies. Three major results were found: (i) the feasibility of thermo-accumulation in acclimatization; (ii) the reduction of operational cost of electricity for commercial air-conditioning users; (iii) a proposal for differentiated retailing tariff billings. To highlight the conclusions of the work, the use of the thermo-accumulation technology by electric companies was shown to be unmistakable. On the one hand it provides better tariff schemes for consumers and on the other it is environmentally friendly.

APA, Harvard, Vancouver, ISO, and other styles

10

Pauletti, Luiz Celestino. "Um estudo de uso de gradador de tensão em motores de indução monofásicos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/17566.

Full text

Abstract:

O motor de indução é, talvez, o mais robusto e, certamente, um dos motores mais comumente usados. Graças à simplicidade de sua construção, do seu baixo custo, confiabilidade e rendimento relativamente alto com carga nominal é provável que ele permaneça sendo a principal fonte de transformação de energia elétrica em energia mecânica nas aplicações industriais e comerciais por um futuro previsível. O estudo de economia de energia pela redução de perdas é o objetivo do presente estudo. Os motores de indução operam regularmente com fluxo quase constante no entreferro e, portanto, com perdas magnéticas quase constantes. A utilização de um circuito gradador de tensão em série com a alimentação do motor para reduzir o fluxo no entreferro pela redução da tensão aplicada quando a carga não requer fluxo total é o objeto de análise neste estudo. Com a redução da tensão, para manter o conjugado de operação, a velocidade de rotação diminui, ou seja, há um aumento no escorregamento até um valor ótimo para reduzir as perdas totais. Então, esperaria-se que com a redução da tensão aplicada, as perdas magnéticas decresceriam e a eficiência total cresceria. Via de regra, no motor de indução, dada a característica mergulhante de sua curva Conjugado x Velocidade na região em torno da velocidade nominal, o conjugado varia muito mais que a velocidade. Para operação eficiente, a sua tensão aplicada deve ser função da carga que traciona. É objetivo desse trabalho estudar um dispositivo que, colocado em série com a fonte de alimentação de um motor de indução de CA, promove a redução de potência fornecida ao motor, quando a carga aplicada ao motor é menor que a carga nominal. Uma análise da redução da tensão senoidal aplicada através de um auto-transformador de tensão variável é comparada com a redução da tensão através de um circuito gradador baseado em tiristores. A melhor tensão a ser obtida é a que reduz as perdas magnéticas ao mínimo, para cargas que não requerem o fluxo total no entreferro como quando da tensão nominal aplicada. As limitações do processo são estudadas e apresentadas.
The induction motor is perhaps the most rugged, and certainly one of the most commonly used motors. With simply construction, low cost, reliability and efficiency relatively high with rated-load it seems to be a good way to convert electric energy into mechanical energy for industrial and domestic applications for a predictable future. An economy in energy consumption by loss reduction is the goal of this study. The induction motors as normal operate with constant flux in the air-gap and, hence with almost constant losses in the core. The use of a voltage gradador circuit in series with the voltage source applied to the motor for flux reduction in the air-gap by reduction of the voltage when the load do not need full-flux is this study proposal. Hence, with applied voltage reduction, to keep the operational torque, the motor rotation decreases or the slip increases to an optimum value to reduce the total core losses and increase the efficiency. As a rule, the induction motor, by the dip characteristic of the torque x speed curve in the region near the nominal speed, the torque changes much more then the speed. For efficient operation, the applied voltage should be a function of the load. It is the goal or aim of this work to study a device which, when placed in series with the power input of an alternating current induction motor, will produce a reduction in power normally provided to the motor when operated in either a condition where motor loading is less than a rated load. An analysis of voltage ideal sine wave supply reduction applied by an autotransformer with variable voltage is compared with the voltage reduction using a gradador circuit based on thyristors. The optimal voltage operation is the one that decrease the iron losses to minimum, for partial-load that do not need full-flux in the air-gap as when the full voltage is applied. Limitations in the process are investigated and will be showed.

APA, Harvard, Vancouver, ISO, and other styles

11

Stenhammar, Oscar. "Analysis of factory test data of on-load tap-changers for power transformers." Thesis, Uppsala universitet, Avdelningen för systemteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447236.

Full text

Abstract:

On-load tap-changers (OLTC) are devices in the power grid that keeps the voltage level constant for consumers, regardless of the power demand. Hitachi ABB Power Grids, producer of the OLTC family named VUC, guarantees 30 years of lifetime. Such a pledge requires high standard devices. This thesis has analyzed data from routine tests of switching times in the diverter switch of OLTC’s, performed before devices were put in service. The correlation of part switching times for all units leaving the factory during the past year was evaluated by calculating Pearson’s correlation coefficient. A linear trend was fitted to the data, realizing that the prediction errors, as well as the part switching times, were Gaussian distributed. The time while the resistor vacuum interrupter was open could be predicted within the interval of approximately 2ms with 2 standard deviations accuracy. To classify time series from the routine test as expected or unexpected, a model-based algorithm was implemented. The average switching time for all consecutive switches was used to define expected series. A moving average was implemented to neglect outliers and remove oscillating patterns. The majority of all data was classified as expected time series. The ones who did not, still preserved a good correlation between the part switching times. Examining the relationship between part switching times could be a valuable perspective in further classification of expected time series. The possibility of incorporating measurement of part switching times on OLTC’s in normal operation, to use the knowledge gained by this thesis, was investigated. Position sensors were mounted to measure the position of the lifting yokes, opening and closing the vacuum interrupters. The time while the vacuum interrupter contacts were open could be estimated with better accuracy than the position sensor provided. Unfortunately, those sensors cannot be utilized in normal operation. If other possibilities could be found, perhaps a laser position sensor, the implemented algorithm would be valuable.

APA, Harvard, Vancouver, ISO, and other styles

12

Newell, Philip B. "Methods for determining power output and factors affecting the optimal load during free-standing jump squats." Virtual Press, 2005. http://liblink.bsu.edu/uhtbin/catkey/1315174.

Full text

Abstract:

The purpose of this thesis was to determine the validity of an linear position transducer / force platform method as compared to a 2D video analysis / force platform method for determining power output during free-standing jump squats, and to examine the effects of strength level and sport background on the optimal load for power output. The results showed that the LPT method was not suitable for measuring power output during free-standing jump squats. In addition, the optimal load range was determined for the VA method to occur between 10% and 20% of a predicted 1RM squat. Strength level did not have a significant affect on the optimal load, however, there were differences in strength and power output by sport. It is recommended that future research examine the specific limitations of an LPT for measuring un-constrained movements, as well as the effects of athletic and training background on the optimal load.
School of Physical Education, Sport, and Exercise Science

APA, Harvard, Vancouver, ISO, and other styles

13

Ishaque, Mohammed. "A new method for calculating the economic benefits of varying degrees of power factor correction for industrial plant loads." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4322.

Full text

Abstract:

A comparative study of the economic benefits that can be obtained from different degrees of power factor correction for medium and small scale industrial installations is shown. A new approach for precise calculation of kws and kvars required at different power factors is presented. These calculated values are used to find the return on investments for the capacitors needed for power factor correction. The developed method is easy to use, cost effective, accurate and will help electrical engineers with minimum knowledge of power systems to precisely determine the savings available by improving the power factor of an industrial load.

APA, Harvard, Vancouver, ISO, and other styles

14

Gabriel, Camila Pires Cremasco [UNESP]. "Aplicação da Lógica Fuzzy para avaliação do faturamento do consumo de energia elétrica e demanda de uma empresa de avicultura de postura." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/101828.

Full text

Abstract:

Made available in DSpace on 2014-06-11T19:31:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-07-02Bitstream added on 2014-06-13T19:20:50Z : No. of bitstreams: 1 gabriel_cpc_dr_botfca.pdf: 833335 bytes, checksum: 4475ce35625358eeb8afee9bf905ce59 (MD5)
A região de Bastos-SP é responsável por grande parte da produção brasileira de ovos. Muitas granjas nesta região produzem a própria ração para alimentação de suas aves através da trituração de milho e soja com motores elétricos muitas vezes super-dimensionados, trabalhando em vazio ou em horário de pico. Esta atividade é responsável por grande parte do gasto energético da empresa. Existem dois fatores que avaliam o modo de utilização desta energia, denominados fator de potência ( fp) e fator de carga ( fc), que indicam a eficiência e racionalidade da forma de utilização da energia elétrica, respectivamente. A necessidade de uma avaliação global da utilização da energia, levando em consideração os dois fatores citados, é realizada por especialistas da área energética para a determinação da situação real da empresa. A lógica fuzzy estabelece a criação de algoritmos genéticos, que são capazes de imitar parte do raciocínio humano. Esta lógica aproxima métodos computacionais e o raciocínio humano, o que possibilita a avaliação global da empresa por métodos computacionais e não mais de especialistas da área energética. Estes métodos são sintetizados criando-se um programa computacional baseado em regras criadas a partir desta lógica, que denominamos controlador fuzzy.O presente trabalho preocupou-se em criar um controlador fuzzy para a avaliação do faturamento do consumo de energia elétrica e demanda de potência ativa e reativa em uma empresa de avicultura de postura. Para isto, coletaram-se dados sobre o comportamento dos parâmetros elétricos, tais como: fator de potência, fator de carga, demanda e consumo ativo. A criação de um controlador fuzzy necessita de um processador de entrada, um conjunto de regras lingüísticas, um método de inferência fuzzy e um processador de saída, gerando um número real como saída...
The region of Bastos-SP is responsible for great part of the Brazilian egg production. Many farms in this region produce the proper ration for feeding of its birds through the triturate of maize and soy with electric engines many large sized times, working in emptiness or schedule of peak. This activity is responsible for great part of the energy expense of the company. Two factors exist that evaluate the way of use of this energy, called power factor ( fp) and load factor ( fc), that indicates the efficiency and rationality of the form of use of the electric energy, respectively. The necessity of a global evaluation of the use of the energy, leading in consideration the two cited factors, is carried through by specialists of the energy area for the determination of the real situation of the company. The logic fuzzy establishes the creation of genetic algorithms, that are capable to imitate part of the human reasoning. This logic approaches computational methods and the human reasoning, what it not more than makes possible the global evaluation of the company for computational methods and specialists of the energy area. These methods are synthecized creating a based computational program in rules created from this logic, that we call controller fuzzy.The present work was worried in creating a controller fuzzy for the evaluation of the invoicing of the consumption of electric energy and demand of active and reactive power in a company of position poultry keeping. For this, they had been collected given on the behavior of the electric parameters, such as: factor of power, load factor, demand and active consumption. The creation of a controller fuzzy needs an entrance processor, a set of linguistic rules, a method of inference fuzzy and a processor of exit, generating a real number as exit. Defining the entrance 0 variable as the load and power factor,... (Complete abstract click electronic access below)

APA, Harvard, Vancouver, ISO, and other styles

15

Gabriel, Camila Pires Cremasco 1978. "Aplicação da Lógica Fuzzy para avaliação do faturamento do consumo de energia elétrica e demanda de uma empresa de avicultura de postura /." Botucatu : [s.n.], 2008. http://hdl.handle.net/11449/101828.

Full text

Abstract:

Orientador: Angelo Cataneo
Banca: Helenice de Oliveira Florentino Silva
Banca: Ivam Resina
Banca: Flávio Ferrari Aragon
Banca: Fernando Natal de Pretto
Resumo: A região de Bastos-SP é responsável por grande parte da produção brasileira de ovos. Muitas granjas nesta região produzem a própria ração para alimentação de suas aves através da trituração de milho e soja com motores elétricos muitas vezes super-dimensionados, trabalhando em vazio ou em horário de pico. Esta atividade é responsável por grande parte do gasto energético da empresa. Existem dois fatores que avaliam o modo de utilização desta energia, denominados fator de potência ( fp) e fator de carga ( fc), que indicam a eficiência e racionalidade da forma de utilização da energia elétrica, respectivamente. A necessidade de uma avaliação global da utilização da energia, levando em consideração os dois fatores citados, é realizada por especialistas da área energética para a determinação da situação real da empresa. A lógica fuzzy estabelece a criação de algoritmos genéticos, que são capazes de imitar parte do raciocínio humano. Esta lógica aproxima métodos computacionais e o raciocínio humano, o que possibilita a avaliação global da empresa por métodos computacionais e não mais de especialistas da área energética. Estes métodos são sintetizados criando-se um programa computacional baseado em regras criadas a partir desta lógica, que denominamos controlador fuzzy.O presente trabalho preocupou-se em criar um controlador fuzzy para a avaliação do faturamento do consumo de energia elétrica e demanda de potência ativa e reativa em uma empresa de avicultura de postura. Para isto, coletaram-se dados sobre o comportamento dos parâmetros elétricos, tais como: fator de potência, fator de carga, demanda e consumo ativo. A criação de um controlador fuzzy necessita de um processador de entrada, um conjunto de regras lingüísticas, um método de inferência fuzzy e um processador de saída, gerando um número real como saída... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The region of Bastos-SP is responsible for great part of the Brazilian egg production. Many farms in this region produce the proper ration for feeding of its birds through the triturate of maize and soy with electric engines many large sized times, working in emptiness or schedule of peak. This activity is responsible for great part of the energy expense of the company. Two factors exist that evaluate the way of use of this energy, called power factor ( fp) and load factor ( fc), that indicates the efficiency and rationality of the form of use of the electric energy, respectively. The necessity of a global evaluation of the use of the energy, leading in consideration the two cited factors, is carried through by specialists of the energy area for the determination of the real situation of the company. The logic fuzzy establishes the creation of genetic algorithms, that are capable to imitate part of the human reasoning. This logic approaches computational methods and the human reasoning, what it not more than makes possible the global evaluation of the company for computational methods and specialists of the energy area. These methods are synthecized creating a based computational program in rules created from this logic, that we call controller fuzzy.The present work was worried in creating a controller fuzzy for the evaluation of the invoicing of the consumption of electric energy and demand of active and reactive power in a company of position poultry keeping. For this, they had been collected given on the behavior of the electric parameters, such as: factor of power, load factor, demand and active consumption. The creation of a controller fuzzy needs an entrance processor, a set of linguistic rules, a method of inference fuzzy and a processor of exit, generating a real number as exit. Defining the entrance 0 variable as the load and power factor,... (Complete abstract click electronic access below)
Doutor

APA, Harvard, Vancouver, ISO, and other styles

16

Holmblad, Oskar, and Andreas Olsson. "Effekttoppsreducering via elbilsbatterier : Dess potential vid vinterförhållanden i Halmstad år 2030." Thesis, Högskolan i Halmstad, Akademin för företagande, innovation och hållbarhet, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-44590.

Full text

Abstract:

A transition phase is taking place in Sweden, where the goal is to become a completely climate neutral country by 2045. The transport sector currently accounts for a third of fossil emissions in Sweden, while the transport sector also has the greatest potential to become fossil-free through, forexample, a comprehensive electrification. Bottlenecks in the grid is a challenge that Sweden faces where the existing ability to send powerthrough the country is already highly utilized. Battery storage can partly be the solution to this problem and also support the future needs that a further electrification of the transport sector may cause. Battery storage can, however, be both expensive and require a lot of space. To avoid this, the mobile battery storage that is available in electric cars can be used to convey power to the grid based on need. The technology that performs this bidirectional charging is called V2G (vehicle-to-grid) and has enormous theoretical potential. The number of electric cars in Sweden has increased by 82% duringthe year 2020, which provides good conditions for continuing to investigate the potential for V2G. Previous studies have shown challenges with the technology. The main issues pointed out have been profitability, winter conditions and battery wear, all of which are taken into account in this study. As in all of Sweden, Halmstad needs to plan for its electrification of the transport sector and load consequences on the grid. This study carries out a combined qualitative and quantitative case study that examines how a future electric car fleet can affect Halmstad's local grid. With data from HEM Nät from a winter week that will correspond to extreme conditions for the grid, a model has been developed in Excel to test different proposed scenarios. What is analyzed is how V2G can work in practice depending on where and when charging takes place, and whether power regulation can be profitable for both private individuals and network operator. Results show that some form of power regulation will be needed in the future to deal with the consequences of uncontrolled electric car charging with an ever-larger electric car fleet, and that V2G may be an option. Despite the winter climate and consideration for battery wear, a significant power peak reduction can be achieved if sufficient participation is attained and a good control strategy is found. Financial analysis shows a negative outcome for private individuals who use V2G. The utility services that is provided can on the other hand reduce costs for the network operator through load balancing incentives and reduced subscriptions to overlying networks. This in turn can enable an interest in network operators to introduce local incentives for private individuals' involvement.

APA, Harvard, Vancouver, ISO, and other styles

17

Christovão, Monclar Nogueira. "Modelagem matemática do faturamento de energia elétrica de uma empresa de avicultura de postura na tarifa verde de acordo com indicadores de consumo /." Tupã, 2020. http://hdl.handle.net/11449/192209.

Full text

Abstract:

Orientador: Luís Roberto Almeida Gabriel Filho
Resumo: O consumo crescente por energia elétrica, o seu alto custo e as restrições ambientais tornaram imprescindíveis a utilização eficiente desta energia, bem como a execução de ações e programas que promovam economia de eletricidade. Diversas empresas agroindustriais no Brasil produzem a própria ração para alimentação de seus animais por meio da trituração de grãos e cereais, empregando maquinários movidos a motores elétricos muitas vezes sobredimensionados e operando em horários nos quais as tarifas são onerosas (horário de ponta). Essa atividade é responsável por grande parte do consumo de eletricidade e impacta diretamente os custos de produção. Nesta pesquisa, desenvolveu-se um modelo matemático de faturamento de energia elétrica para uma empresa de avicultura de postura optante pela modalidade tarifária verde. Esse modelo trabalha com equações matemáticas contendo variáveis elétricas necessárias ao cálculo da conta de eletricidade. Os principais parâmetros elétricos são os fatores de potência e de carga, a demanda de potência e o consumo de energia. Atualmente no Brasil, para os consumidores do Grupo A, existem duas modalidades tarifárias disponíveis: a horária verde e a horária azul. O modelo matemático proposto pode ser empregado para as duas modalidades, sendo que cada uma delas possui as suas fórmulas específicas, as quais deverão ser inseridas no software Mathematica criado pela empresa Wolfram Research. A direção da granja cedeu 12 contas de energia elétrica e seus dado... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The increasing consumption of electricity, the high costs and the environmental restrictions made it paramount the efficient use of such energy, as well as actions and programs to promote energy conservation. Several agro-industrial companies in Brazil produce their own animal feed by mashing cereals and grains with the use of electric-motor machines, which are many times oversized and operate at expensive fee times (peak time). This activity is responsible for great part of the electricity consumption and directly impacts the production costs. This study developed a mathematical model of electricity billing for a laying poultry farm that opted for the green fee modality. This model uses mathematical equations containing the electric variables required for the calculation of the electric bill. The main electrical parameters are: the power and the load factors, the power demand, and the active consumption. Currently in Brazil, there are two fee modalities for Group A consumers: the green and the blue hourly fees. The proposed mathematical model can be used for both modalities, and there are specific equations for each of them, which should be entered into the software Mathematica developed by Wolfram Research. The manager of the poultry farm provided 12 electric bills, and their data was entered into the software that created three-dimensional surface graphs and contour maps. Such graphs showed the inversely proportional relation of the bill amounts with the power and load fac... (Complete abstract click electronic access below)
Mestre

APA, Harvard, Vancouver, ISO, and other styles

18

Damazo, Graciliano Antonio. "Modelo de máximo carregamento com fator de potência da demanda ajustável e restrição de segurança /." Bauru, 2020. http://hdl.handle.net/11449/192373.

Full text

Abstract:

Orientador: Edméa Cássia Baptista
Resumo: O problema de maximização da margem de carregamento operacional tem por finalidade determinar a maior demanda de carga em um sistema elétrico de potência que satisfaça todas as restrições operacionais do sistema e de equipamentos. Em linhas gerais, conhecer com precisão a máxima demanda de potência ativa e reativa suportada pelo sistema elétrico de potência para que o mesmo opere em condições satisfatórias é uma informação importante para a operação e planejamento do sistema. Muitos trabalhos, da literatura, formulam o problema de máximo carregamento através de um modelo de otimização contínuo, e mais recentemente, alguns trabalhos apresentam modelos que também passaram a levar em consideração o fator de potência da demanda das barras de carga. Neste trabalho propõe-se um modelo para o problema de máximo carregamento baseado no fator de potência de demanda ajustável e levando em consideração restrições de segurança. O problema de maximização da margem de carregamento operacional será formulado como um problema de programação não linear, não convexo de grande porte com variáveis contínuas e visa maximizar o somatório de potências ativas demandadas pelas barras de carga, respeitando um fator de potência mínimo pré-estabelecidos e restrições de segurança pós-contingência. Destaca-se que uma contribuição do trabalho é que o modelo encontre para o sistema um ponto de operação factível na presença de contingências pré-definidas, além disso, respeita os limites físicos e operacionai... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The problem of maximizing the operating load margin aims to determine the highest load demand in an electrical power system that satisfies all operational constraints of the system and equipment. In general, knowing precisely the maximum demand for active and reactive power supported by the electrical power system, in order that it operates in satisfactory conditions, is an important information for the operation and planning of the system. Many works in the literature formulate the problem of maximum loading through a continuous optimization model, and more recently, some works present models that also started to take into account the power factor of the load bars demand. This work proposes a model for the maximum load problem based on the adjustable demand power factor, taking into account security constraints. The problem of maximizing the operating load margin will be formulated as a non-linear, non-convex large programming problem with continuous variables and aims to maximize the sum of active powers demanded by the load bars, respecting an established minimum power factor and post-contingency security constraints. It is important to highlight that the model also ensures that the system finds a feasible operating point, even in the presence of predefined contingencies, besides; it respects the physical and operational limits provided for in the traditional Optimal Power Flow. The proposed model was tested for the IEEE 14, 30, 118 bus systems, simulated on the GAMS platf... (Complete abstract click electronic access below)
Doutor

APA, Harvard, Vancouver, ISO, and other styles

19

DE, LEON RAFAEL. "Modeling the impact of variable renewable energy sources penetration on supply-demand balance : Analysis of France from 2021 to 2025." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-294583.

Full text

Abstract:

France is planning a strong development of solar photovoltaics (PV) and wind power in the medium term disrupting the power system. This Master Thesis analyzes the impacts of variable renewable energy production on the supply-demand balance from 2021 to 2025 in France. The model used relies on a dynamic programming method. The analysis is based on the assessment of indicators such as price signals, margins, loss of load duration (LOLD), expected energy not served (EENS) and nuclear drop stop that characterize the supply-demand balance and the security of supply of the electricity system. Wind power and PV are two very different technologies. Their load factor is very sizeable as it characterize their seasonality, variability and predictability and has an impact on all medium-term indicators. Wind power and PV have low marginal costs and their production is seasonal and in anti-phase. With new installed capacity, their added production in the supply-demand balance will substitute first the imports from the interconnections until saturation and then nuclear and thermal power plant production. Prices decrease with the same seasonality as the production and need to be considered when establishing the nuclear planning for the years to come. In addition a re-optimization of hydro power is observed. In terms of security of supply, wind power is more efficient than PV when assessing the reduction of LOLD but both are far from the performance of combined cycle gas turbines (CCGT). Lastly, the lack of nuclear production opportunities increases considerably more with PV due to a very localised production during the day which coincides in summer with periods of low consumption. Wind power and PV are two distinct technologies and should not be put in the same category when assessing their impact on the power system.
Frankrike planerar en stark utveckling av solceller (PV) och vindkraft på medellång sikt för att störa kraftsystemet. Detta examensarbete analyserar effekterna av varierande produktion av förnybar energi på balans mellan utbud och efterfrågan från 2021 till 2025 i Frankrike. Modellen som används bygger på en dynamisk programmeringsmetod. Analysen baseras på bedömningen av indikatorer som prissignaler, marginaler, förlust av lasttid (LOLD), förväntad energi som inte serveras (EENS) och kärnkraftsfallstopp som kännetecknar efterfrågan och utbudssäkerheten för el systemet. Vindkraft och solceller är två mycket olika tekniker. Deras belastningsfaktor är mycket stor eftersom den kännetecknar deras säsongsvariation, variation och förutsägbarhet och påverkar alla medellångsiktiga indikatorer. Vindkraft och solceller har låga marginalkostnader och deras produktion är säsongsbetonad och i fas. Med ny installerad kapacitet kommer deras extra produktion i utbuds- och efterfrågan att ersätta importen från sammankopplingarna till mättnad och sedan produktion av kärnkraft och värmekraftverk. Priserna sjunker med samma säsong som produktionen och måste beaktas när kärnkraftsplaneringen fastställs för de kommande åren. Dessutom observeras en återoptimering av vattenkraften. När det gäller försörjningstrygghet är vindkraft effektivare än solceller vid bedömning av minskningen av LOLD men båda är långt ifrån prestanda för kombinerade cykelturbiner (CCGT). Slutligen ökar avsaknaden av kärnkraftsproduktionsmöjligheter betydligt mer med solceller på grund av en mycket lokal produktion under dagen som sammanfaller på sommaren med perioder med låg konsumtion. Vindkraft och solceller är två olika tekniker och bör inte placeras i samma kategori när man bedömer deras inverkan på kraftsystemet.

APA, Harvard, Vancouver, ISO, and other styles

20

Hajdú, Lukáš. "Vliv decentrálních zdrojů na provozování distribuční soustavy 110 kV E.ON." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219014.

Full text

Abstract:

This Master´s thesis deals with problematics related to the connection of new decentralized power sources into electrical power grid. Due to advantageous legislative support of these new, especially photovoltaic power sources, a massive amount of these sources have been connected into the power grid between years 2009 and 2010. For theoretical understanding of processes during a steady-state, the initial parts of this paper are focused on a procedure which solves steady-state on every power line mentioned. When we speak of decentralized power sources connection, it is necessary to mention the connected legislative. National distribution grid operators in collaboration with national regulatory commission have decided on a legislative document Rules of distribution grid operation, which puts a set of demands and requirements on applicants wishing to connect a new power source to the grid. The text of this thesis is focused mainly on demands required after the latest change in 1/2010. Practical part of this work deals with verification of new power source influence on a related power grid and meeting the legislatively required demands. The most important demands are voltage change due to new power source operation and its transfer to other voltage levels, higher harmonics injection, power output fluctuation and last, not least, changes in load flow directions. For reasons previously mentioned an analysis is made and possibilities of reducing or removing of these influences are introduced. To achieve these goals, two computer programs, Siemens Sinaut Spectrum and NetCalc are used.

APA, Harvard, Vancouver, ISO, and other styles

21

Joy, Emmanuel. "Comparison and Study of Load and Resistance Factor Rating (LRFR) and Load Factor Rating (LFR) Methods." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307323579.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Saxena, Vishal. "Interval finite element analysis for load pattern and load combination." Thesis, Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04072004-180207/unrestricted/saxena%5Fvishal%5F200312%5Fms.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Hockenberry, James Richard. "Power system dynamic load modeling." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/42594.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Myska, Martin. "Possibilities with Stirling Engine and High Temperature Thermal Energy Storage in Multi-Energy Carrier System : An analysis of key factors influencing techno-economic perspective of Stirling engine and high-temperature thermal energy storage." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-53407.

Full text

Abstract:

Small and medium-scale companies are trying to minimise their carbon footprint and improve their cash flow, renewable installations are increasing all over the Europe and are expected to do so in following years. However, their dependency on the weather cause pressure on matching the production with demand. An option how to challenge this problem is by using energy storage. The aim of this project is to determine techno-economic benefits of Stirling engine and high temperature thermal energy storage for installation in energy user system and identify key factors that affect the operation of such system. In order to determine these factors simulations in Matlab were conducted. The Matlab linear programming tool Optisolve using dual-simplex algorithm was used. The sensitivity analysis was conducted to test the energy system behaviour. Economic evaluation was done calculating discounted savings. From the results, it can be seen the significant benefit of SE-HT-TES installation is the increased self-consumption of the electricity from PV installation. While the self-consumption in cases when there was no energy storage implemented was around 67 % and in one case as low as 50 % with the SE-HT-TES the value has increased up to 100 %. Energy cost savings are 4.7 % of the cost for the original data set and go up to 6.2 % when simulation with load shift was executed. Simulations have also shown that energy customer with predictable energy demand pattern can achieve higher savings with the very same system. It was also confirmed that for users whose private renewable production does not match load potential savings are 30 % higher compared to the system where energy load peak is matching the PV production peak. Simulations also shown that the customers located in areas with higher electricity price volatility can benefit from such system greatly.

APA, Harvard, Vancouver, ISO, and other styles

25

Andreoli, André Luiz [UNESP]. "Controlador de demanda e fator de potência de baixo custo para unidades consumidoras de energia elétrica." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/89568.

Full text

Abstract:

Made available in DSpace on 2014-06-11T19:24:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-08-12Bitstream added on 2014-06-13T20:11:55Z : No. of bitstreams: 1 andreoli_al_me_bauru.pdf: 2837768 bytes, checksum: 899d0f484921dccf16d7027e336d500b (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O presente trabalho é o resultado de uma pesquisa aplicada ao desenvolvimento de um equipamento eletrônico microprocessado destinado ao controle de demanda máxima e de fator de potência em instalações elétricas. Motivado pelo aumento na demanda e pela limitação nos recursos do sistema elétrico interligado, o uso de equipamentos que permitam o gerenciamento de energia pelo lado da demanda tem se difundido com grande velocidade, pois é o método de racionalização do uso de energia elétrica que apresenta boa relação entre custo e benefícios, trazendo resultados favoráveis em curto prazo. O uso de controladores de demanda máxima e de fator de potência nas instalações atendidas por contratos de fornecimento horo-sazonal é uma forma de garantir que o sistema não ultrapasse os limites contratuais, que resultam em aplicação de multa, e também um modo de se operar o sistema dentro de parâmetros conhecidos evitando perdas excessivas, racionalizando a utilização de seus componentes. Embora não exista regulamentação relacionada a tarifas diferenciadas de energia elétrica para unidades atendidas em baixa tensão, a utilização de controladores de demanda máxima e fator de potência pode trazer à esta classe de consumidores os benefícios do gerenciamento de energia, reduzindo perdas e em muitos casos permitindo a diminuição no valor da fatura de energia. Pelo ponto de vista do fornecimento, a existência de controle de demanda nas unidades consumidoras permite um melhor planejamento e maior aproveitamento do sistema de distribuição, minimizando investimentos no setor. Para aplicação em unidades consumidoras de porte reduzido, os equipamentos de gerenciamento de energia disponíveis no mercado apresentam dois inconvenientes principais: o excesso de recursos que na maioria dos casos não é explorado em sua...
The present work is the result of an applied research to the development of an electronic microcontrolled device used in the control of maximum demand and power factor in small and medium range electric facilities. Stimulated by the increase of demand and limitation of electrical resources of the interconnected system, the use of demand-side energy management devices was increased, since this method is the better mode to provide the energy rationalization, good cost-benefits relationship and presents best results in a short time interval after its implementation. The use of maximum demand and power factor controllers in facilities with differential billing fares is a method of guarantee that the agreement limits will not be exceeded, resulting in penalties, and also a safe mode of system operation, reducing losses and rationalizing the use their components. Although don't exist regulation related to the differential billing applied to low-voltage supplied consumers, the use of maximum demand and power factor controllers can bring to this consumers category the benefits of energy management, reducing losses and in most cases decreasing the energy billing. In the supply point of view, the demand control in consumers units allow the better planning and the best utilization of distribution system, minimizing the investment in this sector. For application in small-size consumer units, the commercially available energy management devices have two inconvenient: excess of resources, in the most cases sub-utilized which increase the price, and the need of a special external energy meter or energy transducer, uncommon in this class of facility. The device developed in this research have an electronic energy measurement system and associated signals independent of the supplier's meter, and also... (Complete abstract click electronic access below)

APA, Harvard, Vancouver, ISO, and other styles

26

Andersson, Magnus. "Wave Power Base Load Properties : A study on wave power base load properties and wind and wave power co-production." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-162309.

Full text

Abstract:

The increased introduction of renewable energy puts pressure on power producers to level peak loads, since the electrical generation from renewable sources more often than not is of intermittent nature. Good base load properties i.e. smooth and even power production over time is one of the most important characteristic a renewable source can show since that implies that less regulating power is required. This project examines the base load properties of wave power and compares them to the base load properties of wind power. This is done based on wave data from Islandsberg on the Swedish west coast and on wind and wave data recorded at Horns rev, a large wind power farm of the west coast of Jutland, Denmark. The wave energy converter (WEC) investigated is a point absorber type WEC, similar to the device developed at Uppsala University / Seabased AB. The results indicate that electrical generation from waves is less fluctuating than generation from winds. Further, wind and wave power co-production would benefit from the time delay in electric wave generation due to that the wind-generated waves continue, after the wind velocities slow down and the wind power output decreases. However, the results also show that Horns rev (and Islandsberg) have rather moderate wave climates and wind-wave co-production would be better balanced inmore energetic wave climates (deeper and/or more exposed waters).

APA, Harvard, Vancouver, ISO, and other styles

27

Zhang, Lujie. "Load-Independent Class-E Power Conversion." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/97601.

Full text

Abstract:

The Class-E topology was presented as a single-switch power amplifier with high efficiency at the optimum condition, where the switch enjoys zero-voltage switching (ZVS) and zero-voltage-derivative switching (ZDS). It is also used in MHz dc-dc converters, and in inverters for wireless power transfer, induction heating, and plasma pulsing. The load current in these applications usually varies over a range. Efficiency of a conventional Class-E design degrades dramatically due to the hard switching beyond the optimum conditions. Keeping ZVS with load change in a Class-E topology is preferred within the load range. Soft switching with load variation is realized by duty cycle modulation with additional transformer, matching network, or resistance compression network. Since two ZVS requirements need to be satisfied in a conventional Class-E design, at least two parameters are tuned under load variation. Thus, changing switching frequency, duty cycle, and component values were used. Impressively, a load-independent Class-E inverter design was presented in 1990 for maintaining ZVS and output voltage under a given load change without tuning any parameters, and it was validated with experimental results recently. The operating principle of this special design (inconsistent with the conventional design) is not elucidated in the published literatures. Load-independency illucidation by a Thevenin Model – A Thevenin model is then established (although Class-E is a nonliear circuit) to explain the load-independency with fixed switching frequency and duty cycle. The input block of a Class-E inverter (Vin, Lin, Cin, and S) behaves as a fixed voltage source vth1 and a fixed capacitive impedance Xth1 in series at switching frequency. When the output block (Lo and Co) is designed to compensate Xth1, the output current phase is always equal to the phase of vth1 with resistive load (satisfies the ZVS requirement of a load-independent design). Thus, soft switching is maintained within load variation. Output voltage is equal to vth1 since Xth1 is canceled, so that the output voltage is constant regardless of output resistance. Load-independency is achieved without adding any components or tuning any parameters. Sequential design and tuning of a load-independent ZVS Class-E inverter with constant voltage based on Thevenin Model - Based on the model, it's found that each circuit parameter is linked to only one of the targeted performance (ZVS, fixed voltage gain, and load range). Thus, the sequential design equations and steps are derived and presented. In each step, the desired performance (e.g. ZVS) now could be used to check and tune component values so that ZVS and fixed voltage gain in the desired load range is guaranteed in the final Class-E inverter, even when component values vary from the expectations. The Thevenin model and the load-independent design is then extended to any duty cycles. A prototype switched at 6.78 MHz with 10-V input, 11.3-V output, and 22.5-W maximum output power was fabricated and tested to validate the theory. Soft switching is maintained with 3% output voltage variation while the output power is reduced tenfold. A load-independent ZVS Class-E inverter with constant current by combining constant voltage design and a trans-susceptance network - A load-independent ZVS Class-E inverter with constant current under load variation is then presented, by combining the presented design (generating a constant voltage) and a trans-susceptance network (transferring the voltage to current). The impact of different types and the positions of the networks are discussed, and LCL network is selected so that both constant current and soft switching are maintained within the load variation. The operation principle, design, and tuning procedures are illustrated. The trade-off between input current ripple, output current amplitude, and the working load range is discussed. The expectations were validated by a design switched at 6.78 MHz with 10-V input, 1.4-A output, and 12.6-W maximum output power. Soft switching is maintained with 16% output current varying over a 10:1 output power range. A "ZVS" Class-E dc-dc converter by adding a diode rectifier bridge and compensate the induced varying capacitance at full-load condition - The load-independent Class-E design is extended to dc-dc converter by adding a diode rectifier bridge followed by the Class-E inverter. The equivalent impedance seen by the inverter consists of a varying capacitance and a varying resistance when the output changes. As illustrated before, ZVS and constant output can only be maintained with resistive load. Since the varying capacitance cannot be compensated for the whole load range, performance with using different compensation is discussed. With the selected full-load compensation, ZVS is achieved at full load condition and slight non-ZVS occurs for the other load conditions. The expectation was validated by a dc-dc converter switched at 6.78 MHz with 11 V input, 12 V output, and 22 W maximum output power. ZVS (including slight non-ZVS) is maintained with 16% output voltage variation over 20:1 output power range. Design of variable Capacitor by connecting two voltage-sensitive capacitors in series and controlling the bias voltage of them - The equivalent varying capacitance in the Class-E dc-dc converter can be compensated in the whole load range only with variable component. The sensitivity of a Class-E power conversion can also be improved by using variable capacitors. Thus, a Voltage Controlled Capacitor (VCC) is presented, based on the intrinsic property of Class II dielectric materials that permittivity changing much with electric field. Its equivalent circuit consists of two identical Class II capacitors in series. By changing the voltage of the common point of the two capacitors (named as control voltage), the two capacitance and the total capacitance are both changed. Its operation principle, measured characteristic, and the SPICE model are illustrated. The capacitance changes from 1 μF to 0.2 μF with a control voltage from 0 V to 25 V, resulting a 440% capacitance range. Since the voltage across the two capacitors (named as output voltage) also affects one of the capacitance when control voltage is applied, the capacitance range drops to only 40% with higher bias in the output voltage. Thus, a Linear Variable Capacitor (LVC) is presented. The equivalent circuit is the same as VCC, while one of the capacitance is designed much higher to mitigate the effect of output voltage. The structure, operational principle, required specifications, design procedures, and component selection were validated by a design example, with 380% maximum capacitance range and less than 20% drop in the designed capacitor voltage range. This work contributes to • Analytical analysis and Thevenin Model in load-independent Class-E power conversion • Variable capacitance with wide range
Doctor of Philosophy
The Class-E topology was presented as a single-switch power amplifier with high efficiency at the optimum condition. Efficiency of a conventional Class-E design degrades with load variation dramatically due to the hard switching beyond the optimum conditions. Since two requirements need to be satisfied for soft switching in a conventional Class-E design, at least two parameters are tuned under load variation. Impressively, a load-independent Class-E inverter design was presented for maintaining Zero-Voltage-Switching (ZVS) and output voltage under a given load change without tuning any parameters, and it was validated with experimental results recently. A Thevenin model is established in this work to explain the realization of load-independency with fixed switching frequency and duty cycle. Based on that, a sequential design and tuning process is presented. A prototype switched at 6.78 MHz with 10-V input, 11.3-V output, and 22.5-W maximum output power was fabricated and tested to validate the theory. Soft switching is maintained with 3% output voltage variation while the output power is reduced tenfold. A load-independent ZVS Class-E inverter with constant current under load variation is then presented, by combining the presented design and a trans-susceptance network. The expectations were validated by a design switched at 6.78 MHz with 10-V input, 1.4-A output, and 12.6-W maximum output power. Soft switching is maintained with 16% output current varying over a 10:1 output power range. The load-independent Class-E design is extended to dc-dc converter by adding a diode rectifier bridge, inducing a varying capacitance. With the selected full-load compensation, ZVS is achieved at full load condition and slight non-ZVS occurs for the other load conditions. The expectation was validated by a dc-dc converter switched at 6.78 MHz with 11 V input, 12 V output, and 22 W maximum output power. ZVS (including slight non-ZVS) is maintained with 16% output voltage variation over 20:1 output power range. The varying capacitance in the Class-E dc-dc converter needs variable component to compensate. Thus, a Voltage Controlled Capacitor (VCC) is presented. The capacitance changes from 1 μF to 0.2 μF with a control voltage from 0 V to 25 V, resulting a 440% capacitance range. The capacitance range drops to only 40% with higher bias in the output voltage. Thus, a Linear Variable Capacitor (LVC) is presented, with 380% maximum capacitance range and less than 20% drop in the designed capacitor voltage range.

APA, Harvard, Vancouver, ISO, and other styles

28

Čáslava, Jiří. "Posouzení možnosti provozu zdrojů v dané oblasti při nestandardních provozních stavech sítě VN." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219385.

Full text

Abstract:

This Master's thesis deals with solution of nonstandard operation connection of E.ON's 22kV distribution network in given area, considering the possibilities of operating dispersed electric power sources currently available, as well as possible power sources connected to the distribution network in the future and its potential operation limitation. A part of this paper is a description of calculation methods used for network evaluation in steady state, with emphasis on linear calculations used by E-Vlivy program, in which the operational possibilities are simulated. Therefore, a description of this program is also included. Suggested operation possibilities correspond with E.ON's valid distribution network operation rules. The outcome of this paper will serve to E.ON's 22kV network's controllers as materials for network operating in nonstandard operation states.

APA, Harvard, Vancouver, ISO, and other styles

29

Penketgorn, Thiwa. "Load and resistance factor design for wood structures." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/104535.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

March, Jason L. "DIGITALLY CONTROLLED, MODULAR ELECTRONIC LOAD." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/657.

Full text

Abstract:

This project entails the design and development of a digitally controlled, modular electronic load. The proposed load is unique from existing designs because it has the added ability to increase its maximum current level by adding identical modules in parallel. Each module is designed to sink a maximum of 5A at 60V but more modules allow for more current. The cost and simplicity of the design are considered such that it can be reproduced in-house to replace, whenever possible, the resistor box for load testing of any analog circuits but more specifically power electronic circuits. The design process as well as the hardware development is explained in detail in this report. Results from hardware testing are also provided.

APA, Harvard, Vancouver, ISO, and other styles

31

Amarasinghe, Kanishka A. "Resonance mode power supplies with power factor correction." Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/23672.

Full text

Abstract:

There is an increasing need for AC-DC converters to draw a pure sinusoidal current at near unity power factor from the AC mains. Most conventional power factor correcting systems employ PWM techniques to overcome the poor power factor being presented to the mains. However, the need for smaller and lighter power processing equipment has motivated the use of higher internal conversion frequencies in the past. In this context, resonant converters are becoming a viable alternative to the conventional PWM controlled power supplies. The thesis presents the implementation of active power factor correction in power supplies, using resonance mode techniques. It reviews the PWM power factor correction circuit topologies previously used. The possibility of converting these PWM topologies to resonant mode versions is discussed with a critical assessment as to the suitability of the semiconductor switching devices available today for deployment in these resonant mode supplies. The thesis also provides an overview of the methods used to model active semiconductor devices. The computer modelling is done using the PSpice microcomputer simulation program. The modifications that are needed to the built in MOSFET model in PSpice, when modeling high frequency circuits is discussed. A new two transistor model which replicates the action of a OTO thyristor is also presented. The new model enables the designer to estimate the device parameters with ease by adopting a short calculation and graphical design procedure, based on the manufacturer's data sheets. The need for a converter with a high efficiency, larger power/weight ratio, high input power factor with reduced line current distortion and reduced cost has led to the development of a new resonant mode converter topology, for power processing. The converter presents a near resistive load to the mains thus ensuring a high input power factor, while providing a stabilised de voltage at the output with a small lOOHz ripple. The supply is therefore ideal for preregulation applications. A description of the modes of operation and the analysis of the power circuit are included in the thesis. The possibility of using the converter for low output voltage applications is also discussed. The design of a 300W, 80kHz prototype model of this circuit is presented in the thesis. The design of the isolation transformer and other magnetic components are described in detail. The selection of circuit components and the design and implementation of the variable frequency control loop are also discussed. An evaluation of the experimental and computer simulated results obtained from the prototype model are included in the presentation. The thesis further presents a zero-current switching quasi-resonant flyback circuit topology with power factor correction. The reasons for using this topology for off-line power conversion applications are discussed. The use of a cascoded combination of a bipolar power transistor and two power MOSFETs i~ the configuration has enabled the circuit to process moderate levels of power while simultaneously switching at high frequencies. This fulfils the fundamental precondition for miniaturisation. It also provides a well regulated DC output voltage with a very small ripple while maintaining a high input power factor. The circuit is therefore ideal for use in mobile applications. A preliminary design of the above circuit, its analysis using PSpice, the design of the control circuit, current limiting and overcurrent protection circuitry and the implementation of closed-loop control are all included in the thesis. The experimental results obtained from a bread board model is also presented with an evaluation of the circuit performance. The power factor correction circuit is finally installed in this supply and the overall converter performance is assessed.

APA, Harvard, Vancouver, ISO, and other styles

32

Collin, Adam John. "Advanced load modelling for power system studies." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8890.

Full text

Abstract:

Although power system load modelling is a mature research area, there is a renewed interest in updating available load models and formulating improved load modelling methodologies. The main drivers of this interest are the introduction of new types of non-conventional (e.g. power electronic interfaced) loads, the requirement to operate power supply systems with increasing levels of renewable distributed generation and the implementation of various load control functionalities (e.g. demand side management). As the majority of existing load models do not allow for a full and precise analysis of these new operating conditions, it is essential to develop new load models and update load modelling techniques. This thesis presents a detailed study of modern loads, focussing on the requirements for their correct representation in power system analysis. The developed models of the individual loads are then combined using a new load aggregation methodology for developing aggregate load models, suitable for the analysis of both existing and future power supply systems (so called ’smart grids’). The methodology uses a circuit-based load modelling approach, as this allows reproduction of the instantaneous current waveforms of the modelled load for any given supply voltage. This approach retains all electrical characteristics of the loads and provides a more realistic representation of some important phenomena (e.g. harmonic cancellation and attenuation due to load and supply system interactions) which are often neglected in traditional load modelling procedures. Case studies of the UK residential and commercial load sectors are presented as illustrations of the load aggregation methodology. The results show significant short-term and long-term temporal variations in the load characteristics, which are not available or reported in the existing literature. This information allows for a more comprehensive assessment of demand-side management functionalities and correlation with locally connected distributed generation. Both of these effects are investigated in the thesis by quantifying the possible extent and range of changes in power system performance for some expected near future changes in load configurations and network operating conditions.

APA, Harvard, Vancouver, ISO, and other styles

33

Dai, F. "Load modelling for power system stability studies." Thesis, University of Manchester, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.578290.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Gerber, J. W. (Johann Wessel). "A constant power, load independent microwave source." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52626.

Full text

Abstract:

Thesis (MScEng)--University of Stellenbosch, 2002.
ENGLISH ABSTRACT: In the past few years, a need for consulting on microwave heating has surfaced. Since most specialised microwave components are imported, this adds a hefty price tag in developing the infrastructure for such consultation. This thesis looks at the design oflow cost alternatives for use in the laboratory. A microwave source output with variable output power is often required for consultation. The calculation of product costs may also be simplified if the available microwave power is constant despite load changes. The magnetron as a load was first investigated and a high voltage SMPS was then designed to control the output of the magnetron according to operator / consulting requirements. To ensure adequate feedback of system output and load matching, a dual directional coupler has been designed and implemented. Since the amount of microwave power required has a direct impact on the initial capital expenditure, costs need to be kept low by optimising the system. An impedance matching unit was designed to match the magnetron with the load, saving energy and reducing system costs. Through automation, the system will strive for the optimum load condition without operator intervention.
AFRIKAANSE OPSOMMING: Die afgelope paar jaar het 'n behoefte ontstaan aan konsultasiewerk op die gebied van mikrogolfverhitting. Aangesien gespesialiseerde komponente meestal ingevoer word, bemoeilik die koste daarvan die ontwikkeling van die nodige infrastruktuur vir konsultasie. Hierdie tesis kyk na die ontwerp van goedkoper alternatiewe vir laboratoriumgebruik. 'n Mikrogolf bron met 'n verstelbare kraglewering is dikwels nodig tydens konsultasiewerk. Produk kosteberekinge kan ook vereenvoudig word indien die mikrogolf kraglewering konstant bly, ongeag produk veranderinge. Die magnetron as GS las is eers ondersoek waarna 'n hoogspanning geskakeldekragbron ontwerp is om die uittree van die magnetron te verstel volgens operateur- / konsultasievereistes. 'n Dubbele direksionele koppelaar is ontwerp en by die laboratorium opstelling gevoeg om voldoende terugvoer van die kraglewering en impedansie aanpassing te verseker. Die hoeveelheid mikrogolf drywing wat benodig word, het 'n direkte impak op die aanvanklike kapitale uitgawe vir die stelsel. 'n Optimale stelsel is dus noodsaaklik om kostes te bespaar. 'n Impedansie-aanpassingsnetwerk is ontwerp om die magnetron en las by mekaar aan te pas om sodoende energie en kostes te bespaar. Deur outomatisering streef die stelsel na optimale werkverrigting sonder enige ingryping deur die operateur.

APA, Harvard, Vancouver, ISO, and other styles

35

Eyisi, Chiebuka. "Load Estimation for Electric Power Distribution Networks." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5935.

Full text

Abstract:

In electric power distribution systems, the major determinant in electricity supply strategy is the quantity of demand. Customers need to be accurately represented using updated nodal load information as a requirement for efficient control and operation of the distribution network. In Distribution Load Estimation (DLE), two major categories of data are utilized: historical data and direct real-time measured data. In this thesis, a comprehensive survey on the state-of-the-art methods for estimating loads in distribution networks is presented. Then, a novel method for representing historical data in the form of Representative Load Curves (RLCs) for use in real-time DLE is also described. Adaptive Neuro-Fuzzy Inference Systems (ANFIS) is used in this regard to determine RLCs. An RLC is a curve that represents the behavior of the load during a specified time span; typically daily, weekly or monthly based on historical data. Although RLCs provide insight about the variation of load, it is not accurate enough for estimating real-time load. This therefore, should be used along with real-time measurements to estimate the load more accurately. It is notable that more accurate RLCs lead to better real-time load estimation in distribution networks. This thesis addresses the need to obtain accurate RLCs to assist in the decision-making process pertaining to Radial Distribution Networks (RDNs).This thesis proposes a method based on Adaptive Neuro-Fuzzy Inference Systems (ANFIS) architecture to estimate the RLCs for Distribution Networks. The performance of the method is demonstrated and simulated, on a test 11kV Radial Distribution Network using the MATLAB software. The Mean Absolute Percent Error (MAPE) criterion is used to justify the accuracy of the RLCs.
M.S.E.E.
Masters
Electrical Engineering and Computing
Engineering and Computer Science
Electrical Engineering

APA, Harvard, Vancouver, ISO, and other styles

36

Cimen, Hasan. "Decentralised power system load frequency controller design." Thesis, University of Sussex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244317.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Toner, Patrick Thomas. "Load forecasting for economic power system operation." Thesis, Queen's University Belfast, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317533.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Jensen, Amanda C. "Power Divider Miniaturization with a Variable Load." Thesis, Marquette University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13815232.

Full text

Abstract:

A 3 Tesla (127.72 MHz) Magnetic Resonance system is able to scan with both the body coil and surface coil at the same time due to a technology called simultaneous acquisition, which uses a 4-port power divider, typically a quad hybrid. This functions at 127.72 MHz. The goal is to replicate this function at 1.5 Tesla field strength (63.86 MHz), but to do so would require the power divider to double in size. This space is not available, so methods of miniaturizing the design were investigated. It was found that slow wave structures cannot shrink the quadrature hybrid design enough to fit inside the desired area. Meandering the transmission lines of the hybrid shrinks the design, but is still too large for our application. The use of lumped elements successfully shrinks the design to fit within the desired space.

Both the meander line design and lumped element design were printed on RO4350, a Rogers printed circuit board material. The meander line design meets all of the critical performance requirements, while the lumped element design did not.

The design also had to withstand a variable load and coupling between the coils of the body coil. To test for this, the printed boards were attached to a body coil and a variable attenuator. The meander line design met all the performance requirements and had better performance than the lumped element design.

APA, Harvard, Vancouver, ISO, and other styles

39

Neslen, Cody R. "Negative Conductance Load Modulation RF Power Amplifier." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/312.

Full text

Abstract:

The number of mobile wireless devices on the market has increased substantially over the last decade. The frequency spectrum has become crowded due to the number of devices demanding radio traffic and new modulation schemes have been developed to accommodate the number of users. These new modulation schemes have caused very poor efficiencies in power amplifiers for wireless transmission systems due to high peak-to-average power ratios (PAPR). This thesis first presents the issue with classical power amplifiers in modern modulation systems. A brief overview of current attempts to mitigate this issue is provided. A new RF power amplifier topology is then presented with supporting simulations. The presented amplifier topology utilizes the concept of negative conductance and load modulation. The amplifier operates in two stages, a low power stage and a high power stage. A negative conductance amplifier is utilized during peak power transmission to modulate the load presented to the input amplifier. This topology is shown to greatly improve the power added efficiency of power amplifiers in systems with high PAPR.

APA, Harvard, Vancouver, ISO, and other styles

40

He, Shengyang. "Modeling power system load using intelligent methods." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/12036.

Full text

Abstract:

Master of Science
Department of Electrical Engineering
Shelli K. Starrett
Modern power systems are integrated, complex, dynamic systems. Due to the complexity, power system operation and control need to be analyzed using numerical simulation. The load model is one of the least known models among the many components in the power system operation. The two different load models are the static and dynamic models. The ZIP load model has been extensively studied. This has widely applied to composite load models that could maintain constant impedance, constant current, and/or constant power. In this work, various Neural Networks algorithms and fuzzy logic have been used to obtain these ZIP load model coefficients for determining the percentage of constant impedance, current, or power for the various load buses. The inputs are a combination of voltage, voltage change, and power change, or voltage and power, and the outputs consist of the ZIP load model coefficients for determining the type and the percentage of load at the bus. The trained model is used to predict the type and percentage of constant load at other buses using simulated transient data from the 16-generator system. A small study was also done using a dynamic induction machine model in addition to the ZIP load model. As expected, the results show that the dynamic model is more difficult to determine than the static model.

APA, Harvard, Vancouver, ISO, and other styles

41

Huss, William Reed. "Load forecasting for electric utilities /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487263399023837.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Sjöström, Magnus. "Factor Demand and Market Power." Doctoral thesis, Umeå universitet, Nationalekonomi, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-279.

Full text

Abstract:

The objective of Paper [I] is to analyze potential effects on the Swedish forest sector of a continuing rise in the use of forest resources as fuel in energy generation. An increasing use of forest resources as an energy input may have effects outside the energy sector. In this paper we consider this by estimating a system of demand and supply equations for the four main actors on the Swedish roundwood market. In Paper [II], we estimate a dynamic factor demand model for the Swedish pulp industry. We find weak evidence of adjustment costs for capital. The results suggest that the user cost of capital is a significant determinant of pulp industry investments. We also find that pulp industry investments are insensitive to variations in the price of electricity. Paper [III] proposes a flexible form of adjustment cost function. An empirical illustration shows that the flexible form can detect both convex and non-convex adjustment costs. Furthermore, the flexible form permits testing for the experience effect on adjustment cost. The objective of paper [IV] is to analyze the price formation for wood fuel used by the Swedish district heating sector. According to previous research there is a significant potential for increasing the use of wood fuel in Sweden. The question raised in this paper is why this potential is not realized. According to our results we cannot reject the efficient market hypothesis for all years. The objective of Paper [V] is to test for market power on the market for biofuels. To achieve our objective we make use of the idea of Granger causality. If past values of quantity contribute significantly to the determination of price, quantity is said to Granger cause price, which we will treat as a sign of market power. According to our findings this effect is present.

APA, Harvard, Vancouver, ISO, and other styles

43

Sjöström, Magnus. "Factor demand and market power /." Umeå : Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-279.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Gough, Michael J. "Demand, energy, and power factor." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/25812.

Full text

Abstract:

This paper briefly presents the results of a study of various utility rate schedules from across the United States and describes a video produced to explain some major features of these rate structures. In particular, the demand, energy and power factor sections of each rate schedule are explored to understand the impacts of selected features on utility costs and on evaluation of energy conservation projects. The accompanying video was produced for the Energy Systems Laboratory's Industrial Assessment Center (IAC) at Texas A&M University. This video will be used during industrial audits to explain typical demand, energy and power factor structures and savings potentials that can be realized by implementation of energy conservation retrofit projects, known as energy conservation opportunities (ECO's), that may be presented through the energy audit process.

APA, Harvard, Vancouver, ISO, and other styles

45

Tabarra, M. "Load factor effects on thermally stratified solar storage tanks." Thesis, De Montfort University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356458.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Townson, Peter Gerard Allan Luke. "Load-maintenance interaction : modelling and optimisation /." [St. Lucia, Qld.], 2002. http://adt.library.uq.edu.au/public/adt-QU20021108.134015/index.html.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Anun, Matias. "Electric vehicle power trains : high-performance control for constant power load stabilization." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50093.

Full text

Abstract:

The development of sustainable transport systems has experienced great improvements in the last 15 years. As a result, electric vehicles, namely hybrid electric vehicles (HEVs) and all-electric or battery electric vehicles (BEVs), are slowly starting to coexist with regular internal combustion vehicles around the world. The complex powering structure of automotive electric systems can be described as a distributed multiconverter architecture. In pursuit of performance, constant-power behavior of tightly regulated downstream converters has raised as an important challenge in terms of system stability and controllability. The first part of this work presents the theory and experimental validation of the unstable behavior introduced by constant-power loads (CPLs) in power converters, more precisely in a Buck+Boost cascade converter as the battery charge/discharge unit. The second part of this work presents the derivation of the Circular Switching Surfaces (CSS) and the implementation of the CSS-based control technique for CPL stabilization. The analysis shows that the constant-power load trajectories and the proposed CSS present a wide, stable operating area and near-optimal transient response. Furthermore, impedance analysis of the converter in close-loop control shows advantageous reduced output source impedance. This extremely high dynamic capability prevents the use of bulky DC capacitors for bus stabilization, and allows the implementation of metal-film capacitors, which have reliability advantages over commonly employed electrolytic capacitors, as well as reduced ESR to improve system efficiency. Beyond the improved stabilization properties of the proposed CCS-based controller, a comparison with traditional compensated linear controller and nonlinear SMC highlights significant improvements in terms of dynamic response for sudden CPL changes. Simulation and experimental results are provided to validate the work. The last part of this thesis work presents the design, construction, and testing of a high-power 3-phase converter. This platform is intended for electric motor driving and is able to manage 20kW of power flow and above, making it suitable for high power traction system development. The platform features an Intelligent Power Module (IPM) to provide with flexibility allowing for changing the power module according to the requirements of the development. Testing of the platform was done in a 0.5HP AC induction motor drive controlled with Voltz-per-Hertz control technique. The integration of the BCDU and the high-power 3-phase motor drive platform conform a high-power bidirectional motor drive platform for the development and testing of control techniques for energy management in EV.
Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate

APA, Harvard, Vancouver, ISO, and other styles

48

Zaar, Emil. "Photovoltaic power potential on Gotland: A comparison with load, wind power and power export possibilities." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-295997.

Full text

Abstract:

The Swedish Island of Gotland provides an interesting case of how renewable energy technologies can be combined and integrated into the electricity system. The study simulates the load, wind power production and PV power production to estimate the PV power potential for existing buildings on Gotland. The theoretical PV power potential on Gotland is calculated to be 667 MW. The PV power potential is split between 28% for dwelling buildings, 9% for multi-dwelling buildings, 7% for industry and 56% for other buildings. The current limit for wind power on Gotland is 195 MW. With the installed capacity of 194 MW wind power, an additional of 22 MW of PV power is possible to integrate without increasing the hours of overload on the power cable. With the prospected submarine power cable, a total of 529 MW PV power is possible to integrate with the existing 194 MW of wind power.

APA, Harvard, Vancouver, ISO, and other styles

49

Herbig, Arnim. "On load flow control in electric power systems." Doctoral thesis, KTH, Electric Power Systems, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2919.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Cresswell, Charles. "Steady state load models for power system analysis." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/3846.

Full text

Abstract:

The last full review of load models used for power system studies occurred in the 1980s. Since then, new types of loads have been introduced and system load mix has changed considerably. The examples of newly introduced loads include drive-controlled motors, low energy consumption light sources and other modern power electronic loads. Their numbers have been steadily increasing in recent years, a trend which is expected to escalate. Accordingly, the majority of load models used in traditional power system studies are becoming outdated, as they are unable to accurately represent power demand characteristics of existing and future loads. Therefore, in order to accurately predict both active and non-active power demand characteristics of aggregated modern power system loads in different load sectors (e.g. residential, commercial or industrial), existing load models should be updated and new models developed. This thesis aims to fill this gap by developing individual, generic and aggregated steady state models of the most common loads in use today, as well as of those expected to show significant growth in the future. The component-based approach is adopted for load modelling, where individual load models are obtained in detailed simulations of physical devices. Whenever possible, the developed individual load models are validated by measurements. These detailed individual load models are then simplified and expressed as equivalent circuit and analytical models, which allowed the establishment of generic load models that can be easily aggregated. It should be noted that since all non-active power characteristics are correctly represented, the developed aggregated load models allow for a full harmonic analysis, which is not the case with the standard steady state load models. Therefore, the proposed load models form an extensive library of comprehensive load models that are suitable for use in multiple areas of power system research. Based on the results of research related to typical domestic/residential sector load mix, the newly developed load models are aggregated and then applied to a typical UK/Scotland distribution network. Considerable differences are seen between network characteristics of newly proposed and previously developed models. The voltage distortion of a typical distribution system bus is investigated, and it is shown that distortion of the system voltage is likely to increase significantly in the future. The results of the presented research also suggest that neglecting the harmonic characteristics from the set of general load attributes may introduce errors in standard load flow studies.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Power and load factor'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles