Utilização de índices de estabilidade transitória para a avaliação de segurança dinâmica

Indices that report how much a contingency is stable or unstable in an electrical power system have been the object of several studies in the last decades. In some approaches, indices are obtained from time-domain simulation; others explore the calculation of the stability margin from the so-called direct methods, or even by neural networks.The goal is always to obtain a fast and reliable way of analysing large disturbance that might occur on the power systems. A fast classification in stable and unstable, as a function of transient stability is crucial for a dynamic security analysis. All good propositions as how to analyse contingencies must present some important features: classification of contingencies; precision and reliability; and efficiency computation. Indices obtained from time-domain simulations have been used to classify the contingencies as stable or unstable. These indices are based on the concepts of coherence, transient energy conversion between kinetic energy and potential energy, and three dot products of state variable. The classification of the contingencies using the indices individually is not reliable, since the performance of these indices varies with each simulated condition. However, collapsing these indices into a single one can improve the analysis significantly. In this paper, it is presented the results of an approach to filter the contingencies, by a simple classification of them into stable, unstable or marginal. This classification is performed from the composite indices obtained from step by step simulation with a time period of the clearing time plus 0.5 second. The contingencies originally classified as stable or unstable do not require this extra simulation. The methodology requires an initial effort to obtain the values of the intervals for classification, and the weights. This is performed once for each power system and can be used in different operating conditions and for different contingencies. No misplaced classification o- - ccurred in any of the tests, i.e., we detected no stable case classified as unstable or otherwise. The methodology is thus well fitted for it allows for a rapid conclusion about the stability of th system, for the majority of the contingencies (Stable or Unstable Cases). The tests, results and discussions are presented using two power systems: (1) the IEEE17 system, composed of 17 generators, 162 buses and 284 transmission lines; and (2) a South Brazilian system configuration, with 10 generators, 45 buses and 71 lines.

A construção teórica do real: Uma questão para a produção do conhecimento em educação

The central theme of this article is the research in education. The aim is to bring up the contribution developed by Mirian Limoeiro Cardoso in Brazil for the production of knowledge in education, besides the propositions of foreign authors, often used as references to base of the research. The starting point, here described, is the statement that the empirical real is not the object of knowledge, but what is presented as an object to be known, is always the real that, in different forms, is an object involved by theory. Thinking about the research in this view the necessecity of revision of the meaning of the object to be known, the object that is also an educative action in its different and several manifestations and the discussion of its importance for the teachers? and researchers? formation.

A Hermenêutica no Campo Organizacional: Duas possibilidades interpretativistas de pesquisa

The present text has the objective of presenting theoretical considerations regarding two types of strategy of research: phenomenology and ethnography. Based on a hermeneutic approach, the two conceptual propositions are presented, the first being dealt with in the sociological context, and the second presented as an anthropological basis. Their similar uses in an organizational context - as well as their differences - are highligthed according to the theoretical contributions of authors belonging to the qualitative universe of organizational research. The text reveals, by the presentations of reported theoretical assumptions, the relevance of the interpretative perspective for the conduction of research that has the organization as object of study, in the pursuit of the identification of ways of constructing the social reality that is the result of the analysis of meanings and experiences lived by the participants, highlighting the importance of the bond between researcher and the research object The theoretical discussion regarding the two perspectives allows to observe the competence of the phenomenological and ethnographic research practice within the field of organizational studies, showing their methodological possibilities to identify dynamics that relate to the experience of life, favoring the analysis of the human being as a phenomenon of interpretation. © FECAP.

Práxis intervencionista na escola: experiências de ressignificação, deslocamento e insurgência

Pós-graduação em Artes - IA

Avaliação da suscetibilidade eletromagnética dos cabos metálicos dos sistemas de supervisão, proteção, comunicação e controle de subestações de alta tensão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Propostas para superação da combinatória na organização do discurso musical

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comunicação sinestésica midiática

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O texto e o traço: reflexões sobre as crônicas ilustradas de Arnaldo Jabor

Pós-graduação em Comunicação - FAAC

Estudo e proposição de formas de pavers intertravados para áreas e passeios públicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A produção textual escrita de alunos de 8. série do ensino fundamental

Pós-graduação em Educação - IBRC

Educação, psicanálise e literatura: distanciamento do texto literário no ensino fundamental

Pós-graduação em Educação - IBRC

A temática ambiental e os cursos superiores de turismo do Estado de São Paulo

Pós-graduação em Educação - IBRC

Socialização de professoras em atividades de educação continuada

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Representações sociais: rupturas e protagonismos nas práticas docentes no ensino superior

Pós-graduação em Educação Escolar - FCLAR

Estudo do desempenho de sistemas de aterramento frente às descargas atmosféricas em instalações de baixa e média tensão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)