Sensitivity analysis by neural networks applied to power systems transient stability

This work presents a procedure for transient stability analysis and preventive control of electric power systems, which is formulated by a multilayer feedforward neural network. The neural network training is realized by using the back-propagation algorithm with fuzzy controller and adaptation of the inclination and translation parameters of the nonlinear function. These procedures provide a faster convergence and more precise results, if compared to the traditional back-propagation algorithm. The adaptation of the training rate is effectuated by using the information of the global error and global error variation. After finishing the training, the neural network is capable of estimating the security margin and the sensitivity analysis. Considering this information, it is possible to develop a method for the realization of the security correction (preventive control) for levels considered appropriate to the system, based on generation reallocation and load shedding. An application for a multimachine power system is presented to illustrate the proposed methodology. (c) 2006 Elsevier B.V. All rights reserved.

Mathematical optimisation techniques applied to power system operation and planning

Nowadays, power system operation becomes more complex because of the critical operating conditions resulting from the requirements of a market-driven operation. In this context, efficient methods for optimisation of power system operation and planning become critical to satisfy the operational (technical), financial and economic demands. Therefore, the detailed analysis of modern optimisation techniques as well as their application to the power system problems represent a relevant issue from the scientific and technological points of view. This paper presents a brief overview of the developments on modern mathematical optimisation methods applied to power system operation and planning. Copyright © 2007 Inderscience Enterprises Ltd.

Robust control applied to power flow control in single-phase inverter with LCL filter, using droop control and D-stability

This paper proposes a new methodology to control the power flow between a distributed generator (DG) and the electrical power distribution grid. It is used the droop voltage control to manage the active and reactive power. Through this control a sinusoidal voltage reference is generated to be tracked by voltage loop and this loop generates the current reference for the current loop. The proposed control introduces feed-forward states improving the control performance in order to obtain high quality for the current injected to the grid. The controllers were obtained through the linear matrix inequalities (LMI) using the D-stability analysis to allocate the closed-loop controller poles. Therefore, the results show quick transient response with low oscillations. Thus, this paper presents the proposed control technique, the main simulation results and a prototype with 1000VA was developed in the laboratory in order to demonstrate the feasibility of the proposed control. © 2012 IEEE.

Nietzsche filósofo da educação: vontade de potência e educação

Pós-graduação em Educação - FFC

A crítica nietzscheana à democracia moderna

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

“Será que eu tô gostando de mulher?”: tecnologias de normatização e exclusão da dissidência erótica feminina no interior paulista

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

A redistricting problem applied to meter reading in power distribution networks

The capacitated redistricting problem (CRP) has the objective to redefine, under a given criterion, an initial set of districts of an urban area represented by a geographic network. Each node in the network has different types of demands and each district has a limited capacity. Real-world applications consider more than one criteria in the design of the districts, leading to a multicriteria CRP (MCRP). Examples are found in political districting, sales design, street sweeping, garbage collection and mail delivery. This work addresses the MCRP applied to power meter reading and two criteria are considered: compactness and homogeneity of districts. The proposed solution framework is based on a greedy randomized adaptive search procedure and multicriteria scalarization techniques to approximate the Pareto frontier. The computational experiments show the effectiveness of the method for a set of randomly generated networks and for a real-world network extracted from the city of São Paulo. © 2013 Elsevier Ltd.

Real power losses reduction and loading margin improvement via continuation method

This letter presents an alternative approach for reducing the total real power losses by using a continuation method. Results for two simple test systems and for the IEEE 57-bus system show that this procedure results in larger voltage stability margin. Besides, the reduction of real power losses obtained with this procedure leads to significant money savings and, simultaneously, to voltage profile improvement. Comparison between the solution of an optimal power flow and the proposed method shows that the latter can provide near optimal results and so, it can be a reasonable alternative to power system voltage stability enhancement.

Artificial neural network model of discharge lamps in the power quality context

This paper presents a methodology for modeling high intensity discharge lamps based on artificial neural networks. The methodology provides a model which is able to represent the device operating in the frequency of distribution systems, facing events related to power quality. With the aid of a data acquisition system to monitor the laboratory experiment, and using $$\text{ MATLAB }^{\textregistered }$$ software, data was obtained for the training of two neural networks. These neural networks, working together, were able to represent with high fidelity the behavior of a discharge lamp. The excellent performance obtained by these models allowed the simulation of a group of lamps in a distribution system with shorter simulation time when compared to mathematical models. This fact justified the application of this family of loads in electric power systems. The representation of the device facing power quality disturbances also proved to be a useful tool for more complex studies in distribution systems. © 2013 Brazilian Society for Automatics - SBA.

Aplicação e análise do uso racional de energia elétrica na Fazenda Experimental Lageado-UNESP, Botucatu-SP

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

A importância de Scotus na concepção de história de Arendt

The objective of this study is to discuss the notion of history in Arendt, from the importance that needs the thought of Duns Scotus, particularly with regard to the primacy of the will. For the author, Scotus was a medieval thinkers to emphasize the role of free will as power in the face of intellect attached to the natural activity. The freedom to get an act featuring a world ruled by contingency. Now, for Arendt, that freedom is consistent with your idea of authentic political, and base a public space, defined by word and action of individuals. The history, which takes place from political activity, received various treatments, from Greek antiquity to the modern conception of process. It joined the idealistic conceptions, establishing universal ways of defining the future. However, if freedom is to characterize the vita activa, the history must seek the meaning of the facts to scrutinize their singular aspects, which fell to the continuo of universal explanation of the official history. It is, therefore, to approach the history from the perspective of singular narrative, from the spectators, those who founded the public space. Hence the importance of bipolar concepts such as nature and freedom, necessity and contingency, will and intellect, as Scotus.

A educação matemática e o cuidado de si: possibilidades foucaultianas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Revolução constitucionalista de 32: principais motivações da Frente Única Paulista

This paper aims to analyze the Constitutionalist Movement in 1932, trying to understand, more specifically, the political end sought by the Front Unique Paulista, on a literal translation, union of the political parties of São Paulo (Republican Party Paulista and Democratic Party). The research is motivated by the need to understand the political project of FUP with the movement and the existing motivations why it was articulated. The comprehension of the constitutionalists' reasons is relevant to understanding the history of the revolution, from its origin to its outcome. Based on literature and its historical analysis, the paper will demonstrate that the Front, with the advent of the Constitutionalist Revolution of 1932, had as its main purpose regain political control of the state of São Paulo lost with the revolution of 1930. More than the vaunted concern with the implementation of a new constitution for the nation, the FUP leaders had intended to retrieve the lost power with the movement of 30 and the rise of Getulio Vargas to power. Under a banner to fight for a new constitution and the expected change from a totalitarian and centralized state imposed by Vargas for a more autonomous state, the cause of São Paulo enticed sympathy and support from the community, whose social history always harbored separatist ideas, even that they have never been carried out to its ultimate consequences

O militarismo no Uruguai

Desde muito cedo, ainda no século XIX, o Uruguai vem desenvolvendo uma política democrática baseada na educação, ao que pode ser creditado o afastamento das suas Forças Armadas da participação política. Entretanto, o sistema partidário, essencial para o desenvolvimento da democracia, não foi suficientemente forte para manter os militares completamente afastados do governo, vivendo o país momentos de militarismo. O propósito deste trabalho é repassar o processo político uruguaio destacando os momentos em que as Forças Armadas estiveram mais próximas do poder. Entende-se que compreender o desenvolvimento da política no país é essencial para, já em outro trabalho, avaliar como a educação, especialmente a oferecida às forças armadas, influencia o desenvolvimento e consolidação de uma cultura democrática.

Detection and classification of voltage disturbances using a Fuzzy-ARTMAP-wavelet network

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