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[pt] AVALIAÇÃO DA CONFIABILIDADE DE SISTEMAS DE GERAÇÃO COM FONTES RENOVÁVEIS VIA TÉCNICAS DE SIMULAÇÃO MONTE CARLO E ENTROPIA CRUZADA / [en] RELIABILITY ASSESSMENT OF GENERATING SYSTEMS WITH RENEWABLE SOURCES VIA MONTE CARLO SIMULATION AND CROSS ENTROPY TECHNIQUESRICARDO MARINHO SILVA FILHO 04 October 2021 (has links)
[pt] A avaliação de confiabilidade da capacidade de geração é extremamente útil em diversos estudos de planejamento da expansão, na avaliação dos riscos relacionados ao dimensionamento da reserva operativa e também na programação da manutenção de unidades geradoras. O principal objetivo é avaliar se uma determinada configuração de unidades de geração atende de forma aceitável à carga do sistema, assumindo que os equipamentos de transmissão sejam totalmente confiáveis e sem limitações de capacidade. Na última década, a inserção de fontes renováveis nos sistemas elétricos de potência tem crescido de forma acentuada, na grande maioria dos países desenvolvidos como também em desenvolvimento. As flutuações de suas capacidades de geração se tornaram parte da complexidade do problema de planejamento e operação de redes elétricas, uma vez que dependem das condições ambientais em que foram instaladas. Além disso, representações detalhadas da carga têm se tornado uma preocupação a mais de muitos planejadores, tendo em vista as análises de risco ao atendimento da demanda nessas redes. Novos modelos e ferramentas computacionais devem ser desenvolvidos para tratar dessas variáveis principalmente com dependência espaço-temporal. Esta dissertação apresenta diversos estudos para avaliar a confiabilidade da capacidade de sistemas de geração via simulação Monte Carlo quasi-sequencial (SMC-QS), considerando fontes de geração e carga com forte dependência espaço-temporal. Esta ferramenta é escolhida devido à sua fácil implementação computacional e capacidade de simular eventos cronológicos. A técnica de redução de variância denominada amostragem por importância baseada no método Cross Entropy (CE) foi utilizada em conjunto com a SMC-QS. As simulações terão como base o sistema teste IEEE-RTS 96, o qual é adequada-mente modificado para incluir fontes renováveis eólicas e hídricas. Portanto, o principal objetivo desta dissertação é definir a melhor maneira de lidar com as séries temporais representativas da geração renovável e carga, nos diferentes estágios do método SMC-QS via CE, de modo a maximizar sua eficiência computacional. Vários testes de simulação são realizados com o sistema IEEE-RTS 96 modificado e os resultados obtidos são amplamente discutidos. / [en] The reliability evaluation of the generating capacity is extremely useful in several expansion planning studies, in the assessment of risks related to the requirements of the operating reserve and also in the scheduling of maintenance of generating units. The main objective is to assess whether a given generating configuration meets the system load in an acceptable manner, assuming that the transmission equipment is completely reliable and without capacity limitations. In the last decade, the insertion of renewable sources in electrical power systems has grown markedly, in the vast majority of developed and developing countries. Fluctuations in their generation capacities have become part of the complexity of the problem of planning and operating electrical networks, since they depend on the environmental conditions in which they are installed. In addition, detailed representations of the load have become a concern among many planners, given the risk analyzes to meet demand in these networks. New computational models and tools must be developed to deal with these variables mainly with space-time dependence. This dissertation presents several studies to evaluate the reliability of the capacity of generation systems via quasi-sequential Monte Carlo simulation (QS-MCS), considering generation and load sources with strong space-time dependence. This tool is chosen due to its easy computational implementation and the ability to simulate chronological events. The variance reduction technique named importance sampling based on the cross-entropy (CE) method is used in conjunction with the QS-MCS. The simulations will be carried out with the IEEE-RTS 96 test system, which is adequately modified to include renewable wind and hydro sources. Therefore, the main objective of this dissertation is to define the best way to deal with the time series representing the renewable generation and load, in the different stages of the SMC-QS method via CE, in order to maximize its computational efficiency. Several simulation tests are performed with the modified IEEE-RTS 96 system and the obtained results are widely discussed.
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[en] IMPACT OF LOAD UNCERTAINTIES AND RENEWABLE SOURCES ON THE OPERATING RESERVE REQUIREMENTS IN MULTI-AREA SYSTEMS / [pt] IMPACTO DAS INCERTEZAS DE CARGA E FONTES RENOVÁVEIS NOS REQUISITOS DE RESERVA OPERATIVA EM SISTEMAS MULTIÁREABRUNA DOS GUARANYS MARTINS 27 November 2019 (has links)
[pt] A reserva girante é a parcela da geração que deve estar sincronizada, ou que seja possível sincronizar em tempo hábil, de forma a repor a perda de unidades de geração, suprir acréscimos de demanda devido aos erros de previsão, ou ainda lidar com possíveis flutuações na capacidade de geração de fontes renováveis. Desta forma, é crucial que tal parcela esteja dimensionada de modo a suprir tais necessidades de forma adequada. Para tal, deve-se considerar o perfil da demanda do sistema e também as características do sistema de geração. Estimativas imprecisas da carga elétrica podem levar a ocorrências de cortes de carga. Da mesma forma, um superdimensionamento da reserva pode ter como consequência custos excessivos para o consumidor de energia. Uma representação aceitável para carga é considerá-la como uma variável aleatória. Este tipo de modelagem permite que o valor do pico de carga estimado tenha suas incertezas intrinsecamente consideradas. Assim, considerando as variabilidades inerentes à demanda e à geração, é então possível estimar o risco de não suprimento do sistema por meio de métodos baseados em Simulação Monte Carlo (SMC). Tais métodos têm como principal vantagem uma relativa robustez para avaliação de índices que mensuram numericamente o nível de confiabilidade do sistema: e.g., LOLP (loss of load probability). Nesta dissertação será avaliado o impacto das incertezas associadas à demanda, à variabilidade das fontes renováveis e às falhas em equipamentos no dimensionamento da reserva de geração no âmbito da operação de sistemas elétricos. Serão empregadas técnicas baseadas em SMC para avaliar os níveis de confiabilidade, considerando diversas possibilidades de representação da carga em sistemas multiárea. Dentre os cenários testados e discutidos, calculam-se índices de risco para o sistema e por áreas, para avaliar se o sistema é confiável não apenas como um todo, mas também em cada uma de suas regiões operativas. Para avaliar a metodologia proposta, são realizados testes com o sistema IEEE-RTS (Reliability Test System) de modo a responder se os índices de risco por
área/sistema estão dentro de níveis aceitáveis. Por fim, é avaliado também o efeito da inserção de fontes renováveis intermitentes na reserva do sistema. / [en] The spinning reserve is the generation quota that must be synchronized (or that can be synchronized in a timely manner) with the aim to restore the loss of generation units, to supply increases in demand due to forecast errors, or to cope with generation capacity fluctuations of renewable sources. Thus, it is crucial that such amount is defined so as to adequately meet the required needs. For this, the system load profile and also the generating system characteristics must be duly considered. Inaccurate estimates of electrical demand can lead to the occurrence of load shedding. Similarly, overinvestment in capacity reserve may result in excessive costs to electric energy consumers. An acceptable representation for the load profile is to consider it as a random variable. This type of modeling allows the estimated peak load value to have its uncertainties intrinsically considered. Therefore, considering the inherent variability of demand and generation, it is then possible to estimate the risk of not supplying the system load through methods based on Monte Carlo simulation (SMC). Such methods have as their main advantage a relative robustness for evaluating indices that numerically measure the reliability level of the system; e.g., LOLP (loss of load probability). In this dissertation, the impact of uncertainties associated with demand, the variability of renewable sources and equipment failures will be evaluated in order to size the amount of generating reserve, within the scope of the operation of electric systems. SMC techniques are used to evaluate the reliability levels, considering several possibilities of load representation in a multi-area system. Among different scenarios analyzed, risk indices are calculated for system and areas, in order to assess whether the grid is reliable as a whole and also for all operating regions. In order to evaluate the proposed methodology, tests are performed with the IEEE-RTS (Reliability Test System) to respond if the area/system risk indices are within acceptable levels. Finally, the effect of inserting intermittent renewable sources into the system reserve is also discussed.
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Energetické úspory velkých objektů / Energy saving of large objectsŘehák, Pavel January 2018 (has links)
The aim of this diploma thesis is to evaluate the economical measures using own heat and power production using cogeneration units, use of renewable resources to partially cover the consumption of objects, reduction of thermal losses by evaporation in the outdoor swimming pool and overall increase of waste heat utilization by exchanger heat exchangers from flue gas and heat from waste water.
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Evaluation of Symmetrical Components Theory in Power Systems with Renewable SourcesDanylov, Daniil January 2021 (has links)
Rapidly growing Inverter- Based Resources (IBR) have different fault properties compared to Synchronous Generators (SG). Therefore, it is necessary to study the fault behavior of systems that contain different types of IBR and compare it to the conventional system responses in order to understand what steps should be taken to adapt conventional protection settings for new types of sources. For a two bus model, it is found out that sequence profiles in a system with one IBR are different from those observed in conventional system. Thermal and electrical limitations of the power electronics reduce the fault current from the IBR significantly, driving negative sequence current to small values compared to conventional sources. This is true for all studied types of IBR. Moreover, if IBR is connected to the grid through one line only, during Three Phase Fault (3hp) it is possible to lose synchronism with grid due to erroneous estimation of the grid angle through the Phase-Locked Loop (PLL). Verification of the obtained results is made through comparison to the Fault Recordings taken from the protection relays placed at substations. It is shown that for some faults simulation results can predict the behavior of symmetrical components in the network whereas for others they do not. To explain the latter behavior modifications to the sequence networks are proposed. / Snabbt växande inverterbaserade resurser (IBR) har olika felinmatningsegenskaper jämfört med synkrongeneratorer (SG). Därför är det nödvändigt att studera felbeteende hos system som innehåller olika typer av IBR och jämför det med konventionella källor för att kunna förstå vilka steg som ska göras för att anpassa konventionella skyddsinställningar för nya typer av källor. Under litteraturöversikten introduktion till det fast jordade systemet och dess speciella fall med isolerad transformatorjordning är klar. Kort introduktion till den studerade IBR och typer av simulerade fel görs också. För en tvåbussmodell har det visat sig att sekvensprofiler i ett system med en IBR skiljer sig från de som observerats i konventionella system. Termisk och elektrisk begränsningar i kraftelektroniska komponenter minskar felströmmen från IBR avsevärt och driver negativ sekvensström till små värden jämfört med konventionella källor. Detta gäller för alla studerade typer av IBR. Dessutom, om IBR är ansluten till nätet endast genom en linje, är det möjligt under trefasfel (3hp) att tappa synkronisering med nätet på grund av felaktig uppskattning av fasvinkeln genom styrsystemets faslåst slinga (PLL). Verifiering av de erhållna resultaten görs genom jämförelse med Fel Inspelningar från reläet placerade på transformatorstationer. Det visas att för vissa fel simuleringsresultat kan förutsäga symmetriska komponenters beteende i nätverket medan andra inte gör det. För att förklara de senare beteendena föreslås modifieringar i sekvensnätverket.
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Thermal Snail : Design and Performance Evaluation of a Non-Electronic Autonomous Vehiclefor Harnessing Thermal Expansion of Volatile Fluid for MovementChen, Xin, Velin, Benjamin January 2024 (has links)
No description available.
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Akumulace energie z OZE / Accumulation of Energy from Renewable Energy SourcesHeller, Ondřej January 2010 (has links)
The objective of the first part of master’s thesis is mapping the potential of various types of renewable sources in Europe and Czech Republic, especially solar energy, wind energy, water energy and biomass. There are described principals and ways of energy generation from these sources, brief overview of current technologies, and also their advantages and limitations. An important part is electric supply continuity from renewable sources, there are large differences and the resulting to restrictions on construction and connecting the units to the power system. In this work there are mentioned some impacts on network and rates of change of supply, some sources are also evaluated in terms of maximum power, that can be connected to the power system in our country. The conclusion of the first part is dedicated to energy storage technologies, which are suitable and usable for renewable sources, there are described their principals, properties, status of development and types of aplications, in which these technologies are used. This chapter also focusses on the price level of each technology. The second part of the thesis deals with 1 MWp on-grid photovoltaic power plant design. This design includes also the redox flow batteries accumulation, the first variant calculates on 24-hour steady energy supply, the second optimalized variant calculates on daily energy supply. There are the accumulation system costs estimated and also the payback period for the both variants. Additionally there is also determined minimum penalization for cost-effective operation. The last part is dedicated to changes of impact on the local grid and changes of system impacts, after the accumulation system is installed.
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