This study examined the Lake of Egypt Power Plant operated by Southern Illinois Power Cooperative located on the Lake of Egypt south of Marion, IL. The facility has a 173 MW rated turbine operating on a pulverized coal cyclone boiler and three 33 MW rated turbines operating on an oversized circulating fluidized bed boiler with 120 MW capacity. The first area examined was reduction of auxiliary power consumption possible with the addition of variable frequency drives to the forced draft fan and booster fan motors. Included in this examination was an analysis of the economic and environmental impact of such a reduction. From the analysis an annual savings of 24.4 GWh of electricity is possible. The second area examined was the generation capacity lost due to condenser fouling and the possible reduction in facility emissions with altered condenser treatment. From the analysis an additional 3.0 MW of capacity facility wide is possible or a reduction steam production of 1.5% for each boiler.

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.

Induction motors and Variable Frequency Drives (VFDs) are widely used in industry to drive machinery trains. However, some mechanical trains driven by VFD-motor systems have encountered torsional vibration problems. This vibration can induce large stresses on shafts and couplings, and reduce the lifetime of these mechanical parts. Long before the designed lifetime, the mechanical train may encounter failure. This thesis focuses on VFDs with voltage source rectifiers for squirrel-cage induction motors of open-loop Volts/Hertz and closed-loop Field Oriented Control (FOC). First, the torsional vibration problems induced by VFDs are introduced. Then, the mathematical model for a squirrel-cage induction motor is given. Two common control methods used in VFD are discussed - open-loop Volts/Hertz and closed-loop FOC. SimPowerSystems and SimMechanics are used as the modeling software for electrical systems and mechanical systems respectively. Based on the models and software, two interface methods are provided for modeling the coupled system. A simple system is tested to verify the interface methods. The study of open-loop Volts/Hertz control method is performed. The closed-form of electromagnetic torque sideband frequency due to Pulse Width Modulation is given. A torsional resonance case is illustrated. The effects of non-ideal power switches are studied, which shows little in uence on the system response but which uses little energy consumption. A study of a non-ideal DC bus indicates that a DC bus voltage ripple can also induce a big torsional vibration. Next, the study of the closed-loop FOC control method is presented. Simulation for a complete VFD machinery train is performed. With the recti er and DC bus dynamic braking, the system shows a better performance than the ideal-DC bus case. Lastly, a parametric study of the FOC controller is performed. The effects of primary parameters are discussed. The results indicate that some control parameters (i.e. speed ramps, proportional gain in speed PI controller) are also responsible for the mechanical torsional vibration.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / The following thesis looks into modeling a chilled water system equipped with variable speed drives on different piece of equipment and optimization of system setpoints to achieve energy savings. The research was done by collecting data from a case-study and developing a system of component models that could be linked to simulate the overall system operation.

The purpose of the study was to cover the impact of variable frequency drives in to-day's industry. A partial aim was also to study perspectives regarding the advantages and disadvantages of the variable frequency drive, its function based on sustainability, production efficiency and demand. The study was based on a qualitative research method, and the empirical material has been based on six semi-structured interviews from industries that currently use variable frequency drives. The results and parts of the study’s purpose were analysed based on previous research and theoretical perspectives. The results mainly show that variable frequency drives contribute to energy savings in our industries. Energy saving was also seen as one of the component's main ad-vantages, followed by the fact that it was considered cost effective in relation to its long lifetime. The cost and complexity of the product were identified as the compo-nent's disadvantages. In relation to sustainability, variable frequency drives mainly match with two of the goals in Agenda 2030, sustainability goals 9 and 12. In this regard, the variable fre-quency drives energy saving is central to the product from a sustainability point of view. In relation to production efficiency, variable frequency drives were found to be more energy efficient, and for that reason affect the process flow for the better, which indicates increased production efficiency. The component was considered as a flexible production solution that enables flow control, as well as maintaining a con-sistent quality of the production flow. Based on the results of the study, the demand that exist today for variable frequency drives only seems to increase. It is stated that there is a great demand today, while depending on the nation, it only seems to be expanding.

System characteristics of automated pumping systems may change due to wear, aging of piping, and accumulation of deposits in the system and/or due to configuration changes. Such changes might result in conflicts between the controlling algorithms and the actual system requirements for each particular case. The said mismatch between the actual physical system and the software controlling it, may result in inefficient operation of the pump which may even lead to total system failures (overpressurization of instrumentation and sensing elements etc.) due to temporary malfunctioning of the system components or permanent damages incurred by them during operating under unsuitable conditions. It is intended in this study to design and construct an experimental automated pump bench with operational components (mechanical, electronical and instrumentation etc.), serving in a system introducing multiple geometric heads and its controlling and monitoring software in order to visualize effects of the above-mentioned cases for education and training purposes. System characteristics data acquisition module (system test module) provides the means of recognizing new pump and system characteristics, provided that they were changed due to some reason (throttled valve, changed pump speed, changed flowrate or elevation of discharge etc.). Then the pump operation module enables users to make comparative judgments by observing the effects of the abovementioned changes. Above-mentioned testing sequence and monitoring of changing physical quantities were achieved by employing four pressure transducers, a custom made DC motor operated -throttling valve with position feedback which was designed and constructed specifically for this study and a variable frequency drive (VFD) which were all connected to a custom made Main Control Circuit (MCC) Board.

This master thesis deals with the mechanical and electrical design of the drive of the inclined construction lift. Individual components are selected in the design. Furthermore, a theoretical research is carried out regarding wireless modules and logic controllers. The selection of sensors is made and the method of retrieving signals from sensors and converting them into iputs the control circuits is also outlined. A program is written in Arduino IDE that wirelessly controls the motion of a motor via variable frequency drive.

Orientador: Walmir de Freitas Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-27T18:46:05Z (GMT). No. of bitstreams: 1 Ricciardi_TiagoRodarte_D.pdf: 6633244 bytes, checksum: bcb56f82b62350db77ed247ac2913cc9 (MD5) Previous issue date: 2015 / Resumo: Modelos matemáticos e computacionais precisos dos diversos componentes de um sistema de energia elétrica são importantes para estudos e simulações em um cenário de planejamento e operação da rede elétrica. Dentre os elementos de um sistema de geração, transmissão e distribuição de energia elétrica, as cargas são as que apresentam maiores dificuldades em serem adequadamente representadas. Embora esse tema de pesquisa tenha sido exaustivamente explorado, a modelagem de carga tem recebido renovada atenção do setor produtivo e da academia por uma série de fatores, dentre os quais podemos destacar a proliferação de medidores eletrônicos, o interesse por modelos de novos equipamentos e a necessidade da representação mais fiel do comportamento de diferentes cargas frente a distúrbios no sistema. Esta tese de doutoramento propõe duas contribuições na linha de pesquisa sobre modelagem de carga em sistemas de energia elétrica. A primeira delas trata-se de um método de modelagem de carga baseado em medições e na detecção de distúrbios naturais de tensão. O procedimento proposto emprega medidores eletrônicos simples, que são instalados junto a instalações em sistemas de distribuição com motivo outro que não o de modelagem de carga. A ideia principal é a de utilizar tais medidores para, paralelamente a função que desempenham, fornecer para a concessionária informações sobre modelos de carga, como um subproduto da função principal que desempenham. A segunda contribuição proposta é na linha da modelagem de carga baseada em templates, uma técnica recentemente proposta na literatura para modelagem dinâmica de cargas industriais de grande porte. Nesta tese é proposto um modelo dinâmico simplificado de motores de velocidade variável controlados via conversores eletrônicos (Variable Frequency Drives ¿ VFDs), o qual é baseado em um modelo modificado de um motor de indução. O modelo proposto é adequado ao contexto da estrutura de modelagem de cargas industriais proposta pela técnica de modelagem baseada em templates e pode ser facilmente agregado e analisado em programas de simulação por parte de usuários sem necessidades de alterações do código fonte / Abstract: Accurate mathematical and computational models from various electric power systems components are important in a scenario of power systems studies and simulations for grid planning and operation. Among the elements in the electricity generation, transmission and distribution systems, the loads are probably the most difficult ones to be accordingly represented. Though this research topic has been exhaustively explored, there is a renewed interest in industry and academia for power systems load modeling, due to several reasons, including the proliferation of smart meters, the appearance of non-conventional types of load and the continuing need for even more confident representation of different load response for system disturbances. This Ph.D. thesis proposes two contributions to power systems load modeling research field. The first one deals with a load modeling method based on measurements and the detection of natural voltage disturbances. The proposed scheme uses simple smart meters, installed close to customers with a main goal other than load modeling. The main idea is to use data provided by those meters to, in parallel to the main function performed by this device, provide to the utility information regarding load models, as a byproduct capable to add value to the investment in this meters. The second contribution is in the template based load modeling, a recently methodology proposed for dynamic modeling of large industrial facilities. In this thesis, a simplified Variable Frequency Drive (VFD) dynamic model is proposed, which one is based on a modified induction machine model. The proposed model is suitable to the dynamic load model structure proposed by the template based methodology and can be easily aggregated and analyzed in simulation software by basic users without the need of programming a complex model / Doutorado / Energia Eletrica / Doutor em Engenharia Elétrica

No description available.