Introdução: A esquizofrenia é um transtorno mental grave e debilitante, que afeta o paciente tanto na sua saúde física como na diminuição de sua capacidade funcional, causando um grande comprometimento ao longo da vida. Apesar de ser possível que o prejuízo em motricidade e prejuízo cognitivo possam representar expressão de um mesmo processo inflamatório sistêmico, pouco se sabe sobre a relação entre motricidade e esquizofrenia. Objetivos: Avaliar a capacidade funcional motora em pacientes esquizofrênicos correlacionando com marcadores inflamatórios, gravidade de doença e tratamento medicamentoso. Métodos: Estudo transversal, por amostra de conveniência, aprovado pelo comitê de ética do Hospital de Clínicas de Porto Alegre (HCPA). Foram recrutados 40 indivíduos com esquizofrenia estabilizada, em tratamento no ambulatório do HCPA. Foi avaliada a capacidade funcional motora através do Teste de Caminhada de 6 Minutos. O nível de significância adotado foi de 5% para todas as variáveis e as análises foram realizadas no programa Statistical Package for the Social Sciences (SPSS, versão 21.0). Resultados: A amostra foi estratificada por anos de doença através do percentil 25, onde apresentou significância no estado civil apresentando uma maior frequência de solteiros e separados em pacientes com o maior tempo de doença (p=0.022). As médias das variáveis funcionais e clínicas laborais que comparadas com médias populacionais apresentaram significância foram: frequência cardíaca (p=0.004), pressão arterial diastólica e sistólica (p=0.001 e p<0.001), frequência respiratória (p<0.001), Proteína C reativa (p=0.015), borg (p<0.001) e Tc6m em homens e mulheres (p<0.001 e p=0.024). No desempenho funcional e dispneia houve uma correlação com a proteína C reativa (r=-0,369 e r= 0,535). Conclusão: O presente estudo mostrou a associação entre o prejuízo funcional com marcadores inflamatórios, principalmente com níveis elevados de PCR. Alterações clínicas foram associadas como reações adversas a utilização de antipsicóticos, apesar de não ser possível descartar também mecanismos inflamatórios antecedendo ambas as alterações. O prejuízo na capacidade funcional associado com aumento da PCR sugere um paciente com sinais de deterioração maior. Todos achados deste estudo apresentam uma contribuição para o entendimento do processo psicótico e abrem caminho para novas intervenções terapêuticas. / Introduction: Schizophrenia is a severe, debilitating mental disorder that affects both the physical health and the functional capacity of patients, causing great impairment throughout the life course. Although physical and cognitive impairments may represent different expressions of a single systemic inflammatory process, little is known about the relationship between motor function and schizophrenia. Objective: To evaluate physical functional capacity in patients with schizophrenia and ascertain whether it correlates with markers of inflammation, disease severity, and pharmacotherapy. Methods: Cross-sectional study using a convenience sampling strategy. Forty patients with stable schizophrenia, undergoing treatment, were recruited from the outpatient psychiatry clinic of Hospital de Clínicas de Porto Alegre (HCPA), a tertiary referral center in Southern Brazil. The 6-minute walk test (6MWT) was used to assess physical functional capacity. The significance level was set at 5% for all variables, and all statistical analyses were carried out in SPSS 21.0. The study was approved by the HCPA Research Ethics Committee. Results: The sample was homogeneous and normally distributed. Subjects were stratified by disease duration, which was significantly associated only with marital status (p=0.022). Comparison of mean functional and clinical variables to population averages showed significant differences in heart rate (p=0.004), diastolic (p=0.001) and systolic (p<0.001) blood pressure, respiratory rate (p<0.001), C-reactive protein levels (p=0.015), Borg Scale of Perceived Exertion scores (p<0.001), and 6MWT distances in men (p<0.001) and women (p=0.024). Conclusion: The present study detected an association between functional impairment and markers of inflammation, especially elevated CRP levels, in patients with schizophrenia. Clinical changes were associated with adverse reactions to antipsychotics, although underlying inflammatory mechanisms could not be ruled out. The loss of functional capacity associated with increased CRP suggests a patient with signs of deterioration increased. The findings of this study contribute to current understanding of the psychotic process and may pave the way for novel therapeutic interventions.

Orientador: Eliana Cotta de Faria / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-14T21:51:52Z (GMT). No. of bitstreams: 1 Sodre_FabioLima_D.pdf: 2215244 bytes, checksum: d5f9f9a36b242a13e3536696c1a618e6 (MD5) Previous issue date: 2009 / Resumo: A aterosclerose é uma doença crônica degenerativa das artérias, caracterizada pelo acúmulo de lipídios na parede arterial. Na década de setenta, Zilversmit postulou que o fenômeno pósprandial era promotor da aterosclerose. O mecanismo que conecta o estado pósprandial com a doença cardiovascular (DCV) inclui a disfunção endotelial, estresse oxidativo e inflamação. No presente estudo, foi estabelecida a composição química das subfrações das lipoproteínas de alta densidade (HDLs) em uma população adulta normolipidêmica brasileira e, comparada esta com outras populações. Além disto, as modificações na composição química desta partícula em indivíduos saudáveis normolipidêmicos foram descritas após a ingestão de uma dieta rica em lipídios. Estes dados demonstraram uma diminuição do conteúdo de ésteres de colesterol e aumento de triglicérides nas partículas de HDL, os quais refletem o aumento da atividade da enzima transferidora de ésteres de colesterol (CETP). Estas mudanças levam a uma atividade anti-oxidante reduzida da HDL. Por fim, este estudo evidenciou que a geração intracelular de espécies reativas ao oxigênio (ROS) está reduzida durante o período pósprandial. A diminuição do consumo de oxigênio celular e suas correlações com a geração de ROS indicam que a mitocôndria participa ativamente deste fenômeno. Disfunção endotelial foi outro achado durante este período. No mundo ocidental, o período pósprandial representa uma parte significativa do dia, ressaltando a importância deste estado no desenvolvimento da aterosclerose. A completa elucidação dos mecanismos envolvidos pode melhorar as intervenções dietéticas e levar a efeitos benéficos no combate ao estresse oxidativo e disfunção endotelial no período pós-prandial. / Abstract: Atherosclerosis is a chronic degenerative disease of the arteries, characterized by an accumulation of lipids in arterial walls. In 1970s, Zilversmit postulated that postprandial phenomenon was a promoter of atherosclerosis. The mechanisms that link the postprandial state with CVD include endothelial dysfunction, oxidative stress and inflammation. In present study, the chemical composition of high density lipoproteins (HDLs) subfractions in a Brazilian adult normolipidemic population was determinated and compared it with others populations. In addition, the modifications in chemical composition of this particle in healthy normolipidemic subjects after an intake of a fat-rich meal, was described. This data presents a diminished core content of cholesteryl ester (CE) and elevated triglyceride (TG) of postprandial HDL particles, which reflected enhanced activity of cholesteryl ester transfer protein (CETP). These changes lead to an impaired antioxidative activity of dense HDL. Finally, this study provides evidence that intracellular reactive oxygen species (ROS) generation is reduced during the postprandial period. The reduction of oxygen consumption and it correlation with ROS generation suggests that mitochondria plays a pivotal role in this phenomenon. Endothelial dysfunction was also found during this period. In western societies, a significant part of the day is spent in the postprandial state, further emphasising the importance of this period in the development of atherosclerosis. The complete elucidation of the involved mechanisms may improve the appropriateness of such dietary intervention supported by beneficial effects on postprandial oxidative stress and endothelial dysfunction. / Doutorado / Clinica Medica / Doutor em Clínica Médica

As cores sempre exerceram fascínio sobre a humanidade e, por toda a história, os compostos coloridos sempre foram considerados ferramentas atrativas nas atividades comerciais. Os corantes sintéticos são amplamente utilizados na indústria têxtil, nas impressões de papel e fotografia, nas indústrias farmacêuticas, alimentícias e de cosméticos. Estes compostos são considerados importantes contaminantes ambientais, representando sérios riscos à flora, fauna e ao ser humano. Apesar da grande quantidade de corantes disponíveis, os estudos sobre a toxicidade desses compostos são escassos e pouco se sabe a respeito dos efeitos genotóxicos destas substâncias. Dentro deste contexto, o presente trabalho avaliou o potencial genotóxico dos corantes Sudan III, Vat Green 3, Reactive Orange 16 e Reactive Black 5, utilizando o Ensaio de Micronúcleos em células HepG2. Os corantes Sudan III e Reactive Orange 16 não induziram aumento, estatisticamente significativo, no número total de micronúcleos em relação aos controles, indicando assim que estes corantes não são capazes de induzir mutações cromossômicas no tipo celular e condições testadas. Entretanto, os corantes Vat Green 3 e Reactive Black 5 induziram mutagenicidade, concentrações de 10,0 e 25,0 ?g/mL, e 0,1; 0,25; 0,5 e 1,0 ?g/mL, respectivamente, demonstrada por um efeito concentraçãodependente, no qual há um aumento de MNs até a concentração de 25,0 ?g/mL para o Vat Green 3 e 0,5 ?g/mL para o Reactive Black 5 com p<0,05. Não foram observadas diferenças significativas entre os IDNs calculados para cada tratamento e controle dos corantes testados, indicando que esses corantes não interferem na proliferação celular das HepG2. Dessa forma, conclui-se que dos quatro compostos analisados, os corantes têxteis Vat Green 3 e Reactive Black 5 são capazes de induzir mutações cromossômicas em células HepG2 e, o potencial mutagênico do Reactive Black 5 é maior que o do Vat Green 3 no sistema celular avaliado, uma vez que foi capaz de induzir mutações, em concentrações menores. Os resultados obtidos neste trabalho permitem concluir que cada um desses importantes contaminantes ambientais deve ser avaliado individualmente a fim de proteger o meio ambiente, garantindo assim a proteção da saúde humana. / The colors have always caused fascination in mankind. Throughout history, colored compounds have always been considered attractive tools in industrial activities. The synthetic dyes are widely used in textile industry, paper and photography printing, in pharmaceutical, food, and cosmetic industries. These compounds are considered important environmental contaminants, and they can cause serious risks to wildlife and humans. Despite the large number of dyes available, studies on the toxicity of these compounds are scarce and little is known about the genotoxic effects of these substances. This study evaluated the genotoxic potential of the dyes Sudan III, Vat Green 3, Reactive Orange 16 and Reactive Black 5 using the micronucleus assay in HepG2 cells. The dyes Sudan III and, Reactive Orange 16, do not induce an increase statistically significant, in the total number of micronuclei when compared to controls. This result shows that these dyes are not able to induce chromosomal mutations in the cell type under the conditions tested. However, the dyes Vat Green 3 and Reactive Black 5 induced mutagenicity, following a dose-response effect, in which there is an increase of micronuclei until the concentration of 25.0 ?g/mL for Vat Green 3 and 0.5 ?g/mL for Reactive Black 5, with p <0.05. There were no significant differences between the NDI calculated for each treatment and control of the dyes studied, indicating that these dyes do not interfere in HepG2 cell proliferation. Thus, the textile dyes Vat Green 3 and Reactive Black 5 are able to induce chromosomal mutations in HepG2 cells, and the dye Reactive Black 5 is more mutagenic than the dye Vat Green 3, since it induced mutations in cellular system tested at lower concentrations. The results of this study indicate that each one of these important environmental contaminants should be assessed individually in order to protect the environment, thus ensuring the protection of human health.

Casos de malária no Brasil atingiu seu nível mais baixo em 35 anos e o Plasmodium vivax é responsável por 85% dos casos em todo o país. A vigilância epidemilógica da transmissão residual da malária persistente na Amazônia é o próximo grande desafio para os esforços vigentes de eliminação. Esta situação nos levou a avaliar uma estratégia para detecção de portadores do parasito (sintomáticos ou não) em áreas que se aproximam a eliminação da malária. Nossa hipótese é que o monitoramento sistemático de moradores de domicílios com um ou mais casos de malária vivax clínica confirmados pela vigilância passiva de rotina (referido como casos índices) e seus vizinhos tem um melhor custo-benecífio na identificação de novas infecções em relação aos inquéritos em massa da população em geral. Para testar essa hipótese, foram recrutados 41 casos índices (24 indivíduos classificados como autóctones, 11 como possíveis recaídas e, seis como casos importados), 163 moradores dos domicílios índices (indivíduos morando na mesma residência do caso índice), 878 moradores vizinhos (moradores de domicílios a um raio de < 3 km) e 841 controles (moradores da mesma localidade, porém a > 5 km de distância do domicílio índice) entre os meses de fevereiro a julho de 2013. Participantes residiam em comunidades rurais pertencentes a Acrelândia, onde o P. vivax é a única espécie implicada na transmissão da malária humana. Todos os participantes foram convidados a fornecerem amostra de sangue capilar para realização do diagnóstico para malária no momento de identificação do caso índice (dia 0), 30, 60 e 180 dias após a primeira visita. Em geral, 6028 análises por microscopia revelaram um aumento na prevalência de malária nos domicílios índices (6,1%; odds ratio [OR] = 36,3, P < 0,001) e vizinhos (2,6%; OR = 13,6, P < 0,001) comparados aos controles (0,1%). Não houve casos positivos para P. falciparum. Moradores dos domicílios índices e vizinhos foram associados com uma maior probabilidade de infecção pelo P. vivax em comparação com os indivíduos controles, após análise ajustada por potenciais confundidores (modelos de regressão logística para efeitos mistos), além desses participantes albergarem > 90% da biomassa parasitária circulante. Nos quatro seguimentos da RCD a microscopia identificou somente 49,5% das infecções diagnosticadas por qPCR, porém 76,8% do total da carga parasitária circulante nas proximidades do domicílio índice. Embora, moradores dos domicílios controles foram responsáveis por 27,6% das amostras positivas por qPCR, 92,6% desses indivíduos eram portadores assintomáticos da infecção, que provavelmente não seriam alvos da RCD. Tipagem molecular dos parasitos utilizando três marcadores polimórficos - msp1F3, MS16 e pv3.27 revelaram alta diversidade de P. vivax, consistente com a complexidade das vias de transmissão e múltiplas fontes de infecção dentro dos aglomerados, potenciais complicações para os programas de eliminação de malária. / Malaria burden in Brazil has reached its lowest levels in 35 years and Plasmodium vivax now accounts for 85% of cases countrywide. The epidemiological surveillance residual malaria transmission entrenched in the Amazon is the next major challenge for ongoing elimination efforts. This situation prompted us to evaluate a strategy for targeted detection of parasite carriers (either symptomatic or asymptomatic) in areas approaching malaria elimination. We hypothesize that repeated screening of households (HHs) with one or more slide-confirmed clinical vivax malaria cases diagnosed by routine passive surveillance (referred to as index cases) and their neighbors is more cost-effective for finding new malaria infections than population-wide mass blood surveys. To test this hypothesis, we recruited 41 index cases (24 subjects classified with indigenous, 11 possible relapsing and 6 cases imported) 163 index household members (subjects sharing the household with index cases), 878 neighbors (subjects living within a radius of up to 3 km from index cases) and 841 controls (subjects living in the same locality, but > 5 km from the index case) between January and July 2013. Study participants lived in rural communities surrounding Acrelândia town, where P. vivax is the only malaria parasite diagnosed in humans. They were invited to contribute finger-prick blood samples, for laboratory diagnosis of malaria, at the time of index case diagnosis (day 0) and 30, 60, and 180 days later. Overall, 6,028 microscopical analysis revealed an increased prevalence of infection in index households (6.1%; odds ratio [OR] = 36.3, P < 0.001) and neighbors (2.6%; OR = 13.6, P < 0.001) compared to controls (0.1%). There were no positive cases for P. falciparum. Subjects in index and neighbor households were significantly more likely to be parasitemic than control households members, after adjusting for potential confounders (mixed-effects logistic regression models), and together harbored > 90% of the P. vivax biomass in study subjects. Four rounds of microscopy-based RCD would identify only 49.5% of the infections diagnosed by qPCR, but 76.8% of the total parasite biomass circulating in the proximity of index HHs. However, control HHs accounted for 27.6% of qPCR-positive samples, 92.6% of them from asymptomatic carriers who were beyond the reach of RCD. Molecular genotyping analysis of parasites with three polymorphic molecular markers (msp1F3, MS16, and Pv3.27) revealed high P. vivax diversity, consistent with complex transmission networks and multiple sources of infection within clusters, potentially complicating malaria elimination efforts.

[pt] Este trabalho faz um estudo de várias metodologias de partição de custos em ambientes competitivos, com o objetivo de se propor algoritmos para a repartição do custo de suporte de reativo entre os diversos acessantes. Entre as várias metodologias estudadas, como por exemplo Nucleolus, Principio da Decomposição e Valor de Shapley, será verificado que o método de Aumann-Shapley é o mais adequado à repartição do custo de suporte de reativo, já que é baseada em custos marginais, bastante compatíveis com um ambiente econômico competitivo. Técnicas de otimização são de extrema importância para aplicação da metodologia de Aumann-Shapley, porque fornecem os multiplicadores de lagrange necessários ao cálculo dos custos marginais de potencia reativa, que são utilizados na repartição de custos de Aumann-Shapley. Neste sentido, é apresentado um algoritmo de pontos interiores, através do qual também se obtém o custo total de suporte reativo. Dois algoritmos para a repartição do custo de suporte de reativo serão então apresentados, um para aplicação ao caso determinístico e outro para o caso estocástico, de modo a se considerar s ocorrência de contingências na rede elétrica. A metodologia proposta é ilustrada em estudos utilizando- se dois sistemas teste: um de 24 barras e outro de 1653 barras. / [en] This work presents the study of some cost allocation methodologies in a competitive framework and proposes algorithms to reactive cost allocation among transmission consumers. Among the studied methodologies, e.g. Nucleolus, Decomposition Principle and Shapley Value, the Aumann-Shapley methodology will be shown to be the most adequate in sharing the cost of reactive support, due to its basis in marginal cost compatible with and economic competitive framework. Optimization techniques are very important to Aumann- Shapley methodology application, because the supplied Lagrange multipliers are extremely important to the evaluation of reactive power marginal cost, carried out in Aumann-Shapley cost allocation. Besides that, an interior point algorithm will be presented, which is used to obtain Lagrange multipliers and to determine the reactive support total cost. Afterwards, two algorithms will be presented to reactive power support cost allocation, one to be applied in a deterministic case and the other to a stochastic case, where contingencies in a electric network are taken into account. The proposed method is illustrated in studies with two electric test systems: one composed by 24 buses and other by 1653 buses.

M.Ing. / This study covers the problem of a periodic distortion and it's electronic compensation. The description and definition of power transfer in a single-phase electrical network is investigated. The various techniques for achieving optimal power transfer are then derived. From this the principle of the compensation of reactive power in an electrical power network is derived using the definition of power transfer. In order to evaluate and illustrate this principle a system configuration, consisting of a controlled source of reactive power is used. Due to the complexity of the system it was initially decided that a computer simulation would serve as an analytical aid. This provides the opportunity to conduct a thorough investigation into the functioning of the proposed compensator. Using the knowledge thus gained. an experimental system was developed. The simulated system is compared to practically obtained results in an experimentally developed compensator in order to evaluate the accuracy and reliability of the simulation. The study then concentrates on the characterization of the two systems as applied in the compensation of reactive power. This analysis also contributes to the identification of deficiencies in the system. The study then concludes with a critical evaluation of the work and suggestions for improvement. This includes the optimization of the total system and the application in industrial power networks.

Inflammatory models of neurodegeneration suggest that higher circulating levels of inflammation can lead to cognitive decline. Despite established independent associations between greater body mass, increased inflammation, and cognitive decline, no prior research has explored whether markers of systemic inflammation might mediate the association between body mass and changes in cognitive functioning. To test such a model, we used two longitudinal subsamples (ns = 9066; 12,561) of aging adults from the English Longitudinal Study of Ageing (ELSA) study, which included two cognitive measures components of memory and executive functioning, as well as measurements of body mass and systemic inflammation, assessed via C-reactive protein (CRP). Greater body mass was indirectly associated with declines in memory and executive functioning over 6 years via relatively higher levels of CRP. Our results suggest that systemic inflammation is one biologically plausible mechanism through which differences in body mass might influence changes in cognitive functioning among aging adults.

>Magister Scientiae - MSc / With a decrease in water availability and arable land, and the ever-increasing reports of toxic chemical pollutants, it is crucial to elucidate plants’ mechanisms of adaptability to these abiotic stressors. South Africa alone accounts for approximately 30% of global Zirconium (Zr) production. However, reports on Zr-induced stress in plants are sparse. Increased mining activity leads to soil contamination which subsequently has harmful effects on crop plants. Under normal conditions B. rapa crop plants flourish, they are rapid in their cycling and circumvent the seed dormancy stage which enables them to have high yields over relatively short periods. However, when unfavourable conditions arise, such as exposure to toxic chemicals and metal ions like Zirconium, the development and growth of B. rapa L., much like other crop plants is affected. More specifically, the damaging effects of Zr is not only attributed directly; as with substitutions of biometals [like Iron (Fe)] in various biomolecules rendering them inactive, but more as a consequence of the production of toxic molecules such as reactive oxygen species (ROS) and methylglyoxal (MG). ROS such as superoxide anion (O₂⁻) and hydrogen peroxide (H₂O₂ ) are known to have signalling roles in plants with reports on their involvement in alleviating seed dormancy and seedling development. However, the signalling roles of MG are not known with regards to plant cells and have been reported more so in animal cells; playing vital roles in fat signalling in diseases such as diabetes. Furthermore MG, in plant and animal cells, directly converts oxygen (O₂) to O₂⁻ and thus increases the cell’s oxidative imbalance, leading to cell damage if O₂⁻ is not rapidly dismutated to H₂O₂ and H₂O by superoxide dismutase (SOD). In turn, H₂O₂ is more stable than O₂⁻ and consequently is more toxic to cells over time. Therefore, H O must be removed as well by a collection of enzymes, such as ascorbate peroxidase (APX) and catalases (CAT). In this study, possible stress-signalling of MG in seedlings under normal conditions and Zr-stress were investigated to establish whether MG at a low dose (6 μM) would benefit seedling growth and development, via a proposed preinduction of the B. rapa L. antioxidant system. Therefore, it was proposed that ROS accumulation due to the exogenous application of MG, would incite the activation of antioxidants and thus mitigate the effects of Zr stress. Physiological tests to determine dry weights (figure 3.2.3) and germination percentage (figure 3.2.2) revealed that MG-treated seedlings yielded an improved biomass and early development compared to Zr-treated seedlings and the control. Membrane damage as assessed by lipid peroxidation viz. Malondialdehyde [MDA] (figure 3.2.4) and conjugated dienes [CD] (figure 3.2.5) also indicated less damage in MG-treated seedlings compared to the Zr-treated set. The chlorophyll content observed was prominent (table 3.1). MG-treated seedlings exhibited a 40% and 15.5% increase compared to Zr-treated seedlings and the control respectively. Moreover cell viability had improved in MG-treated seedlings compared to the control, and in MG+Zr-treated seedlings only a slight increase in cell death occurred despite Zr being present. O₂⁻, H₂O₂ and •OH (figure 4.2.1 – 4.2.3) were investigated in B. rapa L. seedlings in response to Zr and MG by spectrophotometric biochemical assays, as well as their scavenging enzymes, MG accumulation and Gly-I activity. Furthermore, BrGLY1 gene expression and Zr-uptake by ICP-OES were performed. Seedlings treated with MG and Zr respectively showed an increase in ROS. However, all of the ROS observed in MG+Zr-treated seedlings were markedly lower compared to Zr-treated seedlings. SOD and CAT activity observed in MG+Zr-treated seedlings had decreased compared to Zr-treated seedlings, whereas APX activity had increased. Gly-I activity and BrGlyI gene expression had increased across all treatments, showing an elicited response to oxidative stress, due to the observed upregulation, as a result of the accumulated MG. The observed Zr-uptake in MG+Zr-treated seedlings was inhibited by 5-fold compared to Zr-treated seedlings. Clear signs of stress were evident in seedlings treated with Zr compared to the control and MG- treated seedlings, the MG-supplemented (MG and MG+Zr) seedlings displayed a vast improvement comparatively. Modulation of antioxidant activity observed in this study is indicative of an incited response to oxidative stress (figure 4.2.4 – 4.2.6). MG revealed distinct involvement in stress-signalling, ROS levels had increased, although not as severely as with Zr-treated seedlings, but seemingly enough to activate antioxidants without eliciting damage. Furthermore, the proposed early-onset activation of antioxidants has been observed in B. rapa L. seedlings of this study, and as such has resulted in improved growth, development and seed germination. The results of this study has therefore negated the previous reports on MG-toxicity (at high concentrations), and has shed light on further properties of this ubiquitous and inevitably-occurring metabolite at low levels. / National Research Foundation (NRF)

Due to the increasing integration of renewable energy generations, the overvoltage and overload issues in transmission networks have become more significant, and they may occur at various locations. To mitigate the overvoltage issues, traditional solutions which often consider the installation of reactive power compensators such as shunt reactors, SVC, STATCOM may not be cost-effective. To mitigate the overload issues, traditional methods using direct or price-based demand control will affect customers’ electrical experience in that they are inconvenienced greatly. This thesis discusses the flexible tap changing techniques that utilise existing parallel transformers in distribution networks to provide reactive power absorption and demand response services for transmission systems. Among them, the tap stagger technique operates parallel transformers in small different tap positions, i.e. staggered taps, to result in more reactive power absorption from upstream networks. In addition, the tap changing technique changes voltages in the range of statutory limits through the adjustment of tap positions in order to change network demands without directly affecting customers. The aggregated reactive power absorption or demand response from many pairs of parallel transformers in distribution networks could be sufficient to provide VAr or demand support to transmission networks. Network capability studies have been carried out in OpenDSS simulation software to investigate the VAr absorption capability by using tap staggering technique and the demand reduction capability by using tap changing technique. The studies are based on two UK HV distribution networks (132-33kV) with 11 and 28 primary substations (33/11 or 6.6 kV) respectively, and the techniques are applied to parallel transformers in primary substations. Based on the results of the two networks, the capabilities of the whole ENW and the UK distribution networks have been estimated respectively by using linear estimation method. In addition, the VAr absorption capability of the tap stagger technique has been validated by using site trial data. The results show an average VAr absorption capability of 0.89MVAr for a primary substation, 315MVAr for ENW networks and about 2500MVAr for the UK at stagger level 4 and show an average demand reduction capability of 3.1% of the original demand at tap down level 3. The results of capability studies together with the validations results confirm that the flexible tap changing techniques are able to provide transmission networks with effective VAr support and demand response services. To assess network VAr absorption and demand response capability more precisely, this thesis also proposes an online load profile estimation method to estimate the load profiles of the network more accurately if not all substations in the network are monitored. The method uses Peak Load Share values, Euclidean Distance, and some load measurements to estimate load profiles. The method has been validated and compared with a traditional aggregation-based method. The results show an average estimation error of 13% ~ 23% in different conditions using the proposed method, and show an average estimation error reduction from about 47% (using the traditional method) to about 13% (using the proposed method). The results indicate that the developed method has a considerable improvement on the accuracy of load profile estimation.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15728号 / 工博第3342号 / 新制||工||1505(附属図書館) / 28273 / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 森 泰生, 教授 濵地 格, 教授 跡見 晴幸 / 学位規則第4条第1項該当