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Predição da estabilidade a pequenas perturbações em sistemas de energia elétrica: uma abordagem considerando as incertezas da geração eólica
(Universidade Federal de São Carlos, 2025-09-22) Kernbichler, André Mirandez; Fernandes, Ricardo Augusto Souza; https://lattes.cnpq.br/0880243208789454; https://orcid.org/0000-0003-2361-6505; Fernandes, Tatiane Cristina da Costa; https://lattes.cnpq.br/2590102586758022; https://orcid.org/0000-0003-2605-0893; https://lattes.cnpq.br/1023829623964951; Fernandes, Tatiane Cristina da Costa; Ramos, Rodrigo Andrade; Pavani, Ahda Pionkoski Grilo; https://lattes.cnpq.br/2590102586758022; https://lattes.cnpq.br/2081545253471652; https://lattes.cnpq.br/2488515249747169; https://orcid.org/0000-0003-2605-0893; https://orcid.org/0000-0002-2240-1150; https://orcid.org/0000-0002-6198-1397
In the current context, where the demand for sustainable energy sources with low environmental impact is increasing, wind power generation plays a prominent role. However, the high penetration of this energy source imposes new challenges to the operation of Power Systems, particularly involving small-signal stability and the behavior of interarea electromechanical oscillation modes. These challenges become even more critical due to the need for real-time assessment of these modes, which can be supported by Phasor Measurement Units and analytical techniques capable of handling the variability and uncertainty inherent in renewable generation. In this context, this work aims to develop a methodology for small-signal stability prediction in systems with high wind power penetration, using machine learning techniques with a focus on decision trees. This approach enables stability prediction at the pre-fault instant, with low computational cost and fast processing, favoring real-time application. To achieve this, the IEEE 68-bus system was modified by incorporating approximately 40\% of wind power generation and considering variations in load, wind speed, and contingencies according to the $N-1$ criterion, thereby composing the study database. Modal characteristics were then extracted using the Prony method. Next, two approaches for critical mode classification were evaluated: a centralized approach, which aggregates data from multiple PMUs into a single predictive model, and a decentralized approach, based on local models. In both approaches, classifications were analyzed in both binary (stable or unstable) and three classes form (secure, insecure, or unstable), in order to investigate not only binary stability prediction but also the capability of providing more detailed information to the system operator. The centralized approach achieved the best performance, particularly in the three-class classification, reaching an accuracy above 96\% and without errors at critical classification boundaries, meaning without misclassifying unstable cases as stable and vice versa. The decentralized approach, although showing lower accuracy in the three-class classification, presented satisfying results in binary classification, with accuracy above 99\%, proving suitable for contexts with communication constraints or partial system failures. The results confirm the effectiveness of the proposed methodology for small signal stability prediction in systems with high wind power generation penetration, providing support for safe operation and informed decision-making under different operating conditions.
Desigualdades salariais por sexo nos cargos comissionados (CCE E FCE) do Executivo Federal
(Universidade Federal de São Carlos, 2025-09-22) Iwassaki, Athaine Mayumi; Rodrigues, Rodrigo Vilela; https://lattes.cnpq.br/7066100737307566; https://lattes.cnpq.br/6823105219132773; Ferro, Andrea Rodrigues; Moreira, Gustavo Carvalho; https://lattes.cnpq.br/3432809140419477; https://lattes.cnpq.br/4841704095561008
This dissertation analyzes gender inequalities in the occupation and remuneration of Executive Commissioned Positions (CCE) and Executive Commissioned Functions (FCE) within the Brazilian Federal Executive branch. The main objective is to decompose wage and occupational disparities in order to understand the mechanisms that sustain them. A quantitative approach was adopted, using microdata from the Personnel Statistical Panel (PEP) for January 2025. The methodology is based on the Oaxaca-Blinder decomposition to break down the logwage gap between men and women into explained and unexplained components, controlling for variables of education, race/color, and hierarchical level. The results show evidence of a "glass ceiling," characterized by the decreased presence of women in high-leadership strata, and a "concrete ceiling," which more acutely restricts the advancement of Black and Indigenous women. It was found that inequality mechanisms operate in distinct ways: in CCE, the disparity arises mainly from the unequal distribution of men and women across leadership levels (explained component); in FCE, the unexplained component was prominent, suggesting the presence of institutional barriers that penalize women even when they possess equivalent observable characteristics. The study concludes that inequality in the public sector is structural and multifaceted, manifesting not only in access but also in the unequal valuation of professional trajectories, which challenges the notion of a purely formal meritocracy.
Análise preditiva e cenários futuros para manejo de resíduos gerados no tratamento de água na bacia hidrográfica Tietê Jacaré
(Universidade Federal de São Carlos, 2025-09-22) Shiratori, Juliana Costa Leite; Achon, Cali Laguna; https://lattes.cnpq.br/0307406069325793; https://orcid.org/0000-0001-5819-8089; https://lattes.cnpq.br/3481463538017247; https://www.orcid.org/0009-0000-6862-001X; Pinto, Fabiana Alves Fiore; Fava, Maria Clara; https://lattes.cnpq.br/9905539715619645; https://lattes.cnpq.br/2972648262855239; https://orcid.org/0000-0002-2430-8240; https://orcid.org/0000-0002-8201-4339
The management of waste from full-cycle water treatment (LTA and ALAF) is a complex problem for water utilities. This research aims to analyze the management of these wastes in WTPs located in the TIETÊ-JACARÉ Water Resources Management Unit (UGRHI 13), using strategic indicators (SIs) as a tool for predictive analysis and creation of future scenarios. To achieve the proposed objectives, a literature review was conducted to provide theoretical basis and select the most relevant indicators (SIs), a form for data collection during visits to the WTPs was developed and applied, and selected indicators were applied and analyzed. This was followed by the development of three scenarios (realistic, optimistic, and pessimistic) using the multicriteria analysis methodology. Strategic indicators were proposed and applied in WTPs. By applying predictive analysis techniques and future scenarios, it was possible to diagnose and forecast the WTPs and the situation of the water bodies in UGRHI 13, through the construction of three future scenarios (realistic, optimistic, and pessimistic). The application of the Predictive Analysis Score allowed us to visualize the impact of qualitative indicators on the volume of these wastes generated. The scenarios indicated significant variations in the final volume for the year 2035. The results also revealed a decline in the water quality of the water bodies and a lack of monitoring points in the watershed dedicated to public supply, highlighting a need for monitoring more closely related to the water quality of the receiving bodies. A set of six strategic indicators (SIs) was proposed for each waste (LETA and ALAF), three of which are common to both wastes, indirectly assessing their generation.