Proteção em sistemas elétricos com geração distribuída utilizando a transformada wavelet

A typical electrical power system is characterized by centr alization of power gene- ration. However, with the restructuring of the electric sys tem, this topology is changing with the insertion of generators in parallel with the distri bution system (distributed gene- ration) that provides several benefits to be located near to e nergy consumers. Therefore, the integration of distributed generators, especially fro m renewable sources in the Brazi- lian system has been common every year. However, this new sys tem topology may result in new challenges in the field of the power system control, ope ration, and protection. One of the main problems related to the distributed generati on is the islanding formation, witch can result in safety risk to the people and to the power g rid. Among the several islanding protection techniques, passive techniques have low implementation cost and simplicity, requiring only voltage and current measuremen ts to detect system problems. This paper proposes a protection system based on the wavelet transform with overcur- rent and under/overvoltage functions as well as infomation of fault-induced transients in order to provide a fast detection and identification of fault s in the system. The propo- sed protection scheme was evaluated through simulation and experimental studies, with performance similar to the overcurrent and under/overvolt age conventional methods, but with the additional detection of the exact moment of the fault.

Topologia de gerador de distúrbios elétricos baseada em conversores de potência

Electrical disturbances such as voltage sags, interruptions and voltage unbalances might cause serious problems for the end-user and for the companies of generation and transmission of energy. Few years ago, those companies have been using methods and equipments of protection to avoid the disturbances’ presence or to mitigate their effects on the power system. Disturbances generators are used to analyse the behavior of electrical and electronic equipments affected by disturbances. The analysis of those failures allows the development of appropriated protection equipments. In this paper, the development of a disturbances generator based on power converters is presented. The disturbance generator developed is able to generate some symmetrical disturbances, such as: voltage sags, voltage swells and harmonic distortion. The control strategy used in the disturbance generator is based on discrete and repetitive control. The steps of the design of the control and of the filter used for reducing harmonic in the output, are detailed in the text. Are presented the obtained results on computational simulations and the obtained results on laboratory tests.

Teoria de carteiras e a alocação de parques eólicos offshore

The consumption of energy on the planet is currently based on fossil fuels. They are responsible for adverse effects on the environment. Renewables propose solutions for this scenario, but must face issues related to the capacity of the power supply. Wind energy offshore emerging as a promising alternative. The speed and stability are greater winds over oceans, but the variability of these may cause inconvenience to the generation of electric power fluctuations. To reduce this, a combination of wind farms geographically distributed was proposed. The greater the distance between them, the lower the correlation between the wind velocity, increasing the likelihood that together achieve more stable power system with less fluctuations in power generation. The efficient use of production capacity of the wind park however, depends on their distribution in marine environments. The objective of this research was to analyze the optimal allocation of wind farms offshore on the east coast of the U.S. by Modern Portfolio Theory. The Modern Portfolio Theory was used so that the process of building portfolios of wind energy offshore contemplate the particularity of intermittency of wind, through calculations of return and risk of the production of wind farms. The research was conducted with 25.934 observations of energy produced by wind farms 11 hypothetical offshore, from the installation of 01 simulated ocean turbine with a capacity of 5 MW. The data show hourly time resolution and covers the period between January 1, 1998 until December 31, 2002. Through the Matlab R software, six were calculated minimum variance portfolios, each for a period of time distinct. Given the inequality of the variability of wind over time, set up four strategies rebalancing to evaluate the performance of the related portfolios, which enabled us to identify the most beneficial to the stability of the wind energy production offshore. The results showed that the production of wind energy for 1998, 1999, 2000 and 2001 should be considered by the portfolio weights calculated for the same periods, respectively. Energy data for 2002 should use the weights derived from the portfolio calculated in the previous time period. Finally, the production of wind energy in the period 1998-2002 should also be weighted by 1/11. It follows therefore that the portfolios found failed to show reduced levels of variability when compared to the individual production of wind farms hypothetical offshore

Automação da drenagem no teste de produção convencional em tanque cilíndrico

This document aims to improve the quality of the production test in vertical tanks with free water drain pipes, through a device to control the draining system. This proposal consists of an interface detector close to the tank bottle and a control valve on the pipe-drain; they are attached to a remote supervisor system, which will be minimizing the human influence in the conclusion of the test result. And for more consciousness the work shows the importance of the wells production test in the attendance and diagnosis of the productive process, informing the large number of tests executed and problems of the procedure adopted in the field today. There are many possible sources of uncertainty in this kind of test as shown in the experiments realized in the field; the object prototype of this dissertation will be made in the field, based upon the definition of parameters and characteristics of the devices proposal. For a better definition of the draining process the action results of the assessment test are shown, especially changed some for the understand ing of the real process. It shows the proposal details and the configuration that will be used in the tank of Monte Alegre s field Production Station, explaining the interface detector kind and the control system. It is the base to a pilot project now in development, named as the new project classified in the status of the new technology and production improvement of PETROBRAS in Rio Grande do Norte and Ceará. This dissertation concludes that the automation of the conventional test with the draining system will bring benefits both economically as metrologically, because it reduces the uncertainty of the test procedures with free water draining, and also decreases the number of tests with problems

Religiosidade e poder em Ceará Mirim/RN: o caso Monsenhor Rui Miranda.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Repercussão geral e súmula vinculante: os efeitos no controle difuso

Brazil since its first republican constitution has adopted systems of laws control. The review activity was given to three state powers or functions state, Executive, Legislative and Judiciary. However, it appears that in the country along the constitutional history, has stood considerably the jurisdictional control of the most important control. Initially, back in 1891, Brazil adopted the jurisdictional control of diffuse from U.S, whose role in monitoring of standards is delivered to all organs of the judiciary, which may face a case, put on trial, ascertain whether or not the possibility of applying a law, removing its impact in case of unconstitutionality. In 1969, entered in the second legal model of judicial review, the concentrated control of constitutionality, whose inspiration comes from the positivist theory of Hans Kelsen, and was adopted by the Austrian Constitution of 1920. According to the abstract control the supervision of law is given to a Court or Constitutional Court, responsible for the analysis of the legal constitutionality independent of its application to a specific case. In Brazil the role of concentrated control was handed over exclusively to the Supreme Court, which serves as the Constitutional Court, which accumulates that function with other constitutionally provided jurisdiction. Throughout this period, from 1891 until today, Brazil has maintained a dual system of judicial control of legal constitutionality, where they coexist and harmonize the diffuse control exercised by any organ of the Judiciary, and concentrated control of competence the Supreme Court. However, one must recognize that with the advent of the Federal Constitution of 1988, the concentrated control has emerged on the national stage due to two important factors: the expansion of the legal capacity to sue and the inclusion of other ways control, besides the already known Direct Claim of Unconstitutionality. This concentrated control and projection of the Supreme Court s attempt to become a true constitutional court, led to a relative weakening of diffuse control even when performed by the Brazilian Constitutional Court. In order to become a true constitutional court, all decisions handed down by the Supreme in the exercise of constitutional jurisdiction should have the same weight and the same measure, or at least bring improvement to similar effects, once is the responsible for the final word when it comes to constitutional interpretation. Thus, the writs of certiorari and stare decisis were responsible for profound changes in the diffuse control, allowing the Supreme Court can strengthen its decisions even in the diffuse control. These two institutions have substantially changed the legal status of diffuse control, allowing an extension of the effects of decisions handed down by the Supreme Court, so that you can no longer be said that the effects of this control to restrict the disputing parties in the process

Limites formais e materiais ao controle de constitucionalidade pelo Supremo Tribunal Federal

This document approaches the formal and material limits of the constitucionalidade control for the Supreme Federal Court, iniating with the study of the Constitution, detaching its evolution, nature and meanings, passing for its historical evolution, offering still a unconstitutionality concept. Is work the principles as material Constitution, making the distinction entere principles and rules, detaching the characteristics of the principles constitutional, and the basic principle of the Constituition. It analyzes metodologics the historical parameters and of the brazilian system of constitutionality control and detaches the paper of the Supreme Federal Court as positive legislator. It observes the beddings of the constitutionality control and the legitimacy of the Supreme Federal Court. Is examines the performance of the Supreme Federal Court in face of the principle of the legal security. Is offers a vision on the experience of the control of constitutionality in other constries. It still approaches the control of constitutionality in Brazil, detaching the critical points of its formal and material limits. Is verifies the application of the principles constitutional for the Supreme Federal Court in the diffuse control and the intent control of constitutionality, as well as the performance of the Supreme Federal Court ahead of the unconstitutional omissions. It brings to the debate the new perspectives how much to the formal and material limits of the control of constitutionality for the Supreme Federal Court. Objective to elaborate considerations concerning the limits of the constitutional jurisdiction from the model of Constituition, the character politican of the difficulties with respect to the definition of its formal and material limits from the performance of the Supreme Federal Court

Processo de alimentação do Sistema de Informação do HiperDia: Estudo de Caso no município de Natal/RN

Although the records indicate the involvement of the City Christmas in the feeding system HiperDia, a survey conducted by the Health Ministry in 2004 found that the number of entries made in Natal was well below estimate. In order to understand the functioning of HiperDia, we performed this study to analyze the actions taken by the professionals involved in power system HiperDia in Natal / RN. The research has developed into a quantitative perspective, with the design of exploratory case study conducted in the health services that integrate the various levels of the organization who are directly involved with the process of system power HiperDia in Natal / RN , represented here by SMS, health districts and the Family Health Units in the period from August to October 2008.Study participants were 110 professionals, including nurses, physicians, operators, administrator and a coordinator. The survey results showed that feeding HiperDia in Natal was maintained mainly by health professionals and operators. Activities include carrying out the state registration, monitoring, and updating of data transfer routines. They report that the difficulties in the process of feeding data are related to the work of teams and / or lack of structure of the Program of Hypertension and Diabetes (HA and DM), the discontinuity of federal investments in improving the HiperDia and lack of training. We can see then that the process of feeding system on Christmas HiperDia therefore is developing the three levels (SMS, districts and health units), however is not matching the expectations established by MS, considering that the gaps the flow of information are undermining the end result of this process

Projeto e controle de um sistema de aquecimento no Laboratório de Avaliação de Medição em Petróleo

The Oil Measurement Evaluation Laboratory (LAMP), located in the Federal University of Rio Grande do Norte (UFRN), has as main goal to evaluate flow and BS&W meters, where the simulation of a bigger number of operation variable in field, guarantees a less uncertain evaluation. The objective of this work is to purpose a heating system design and implementation, which will control the temperature safely and efficiently in order to evaluate and measure it. Temperature is one of the variables which influence the flow and BS&W accurate measurement, directly affecting the fluid viscosity and density in the experiment. To project the heating system it is of great importance to take the laboratory requirements, conditions and current restrictions into consideration. Three alternatives were evaluated: heat exchanger, internal resistance and external resistance. After the analyses are made in order to choose the best alternative for the heating system in the laboratory, control strategies were determined for it, PID control methods in combination with fuzzy logic were used. Results showed a better performance with fuzzy logic than with classic PID

Projeto de um sistema emulador de escoamentos e vaso de separação primária

The purpose of this study was to develop a pilot plant which the main goal is to emulate a flow peak pressure in a separation vessel. Effect similar that is caused by the production in a slug flow in production wells equipped with the artificial lift method plunger lift. The motivation for its development was the need to test in a plant on a smaller scale, a new technique developed to estimate the gas flow in production wells equipped with plunger lift. To develop it, studies about multiphase flow effects, operation methods of artificial lift in plunger lift wells, industrial instrumentation elements, control valves, vessel sizing separators and measurement systems were done. The methodology used was the definition of process flowcharts, its parameters and how the effects needed would be generated for the success of the experiments. Therefore, control valves, the design and construction of vessels and the acquisition of other equipment used were defined. One of the vessels works as a tank of compressed air that is connected to the separation vessel and generates pulses of gas controlled by a on/off valve. With the emulator system ready, several control experiments were made, being the control of peak flow pressure generation and the flow meter the main experiments, this way, it was confirmed the efficiency of the plant usage in the problem that motivated it. It was concluded that the system is capable of generate effects of flow with peak pressure in a primary separation vessel. Studies such as the estimation of gas flow at the exit of the vessel and several academic studies can be done and tested on a smaller scale and then applied in real plants, avoiding waste of time and money.

Desacoplamento de um gerador síncrono através de um controle adaptativo por modelo de referência baseado em funções de Base radial

An alternative nonlinear technique for decoupling and control is presented. This technique is based on a RBF (Radial Basis Functions) neural network and it is applied to the synchronous generator model. The synchronous generator is a coupled system, in other words, a change at one input variable of the system, changes more than one output. The RBF network will perform the decoupling, separating the control of the following outputs variables: the load angle and flux linkage in the field winding. This technique does not require knowledge of the system parameters and, due the nature of radial basis functions, it shows itself stable to parametric uncertainties, disturbances and simpler when it is applied in control. The RBF decoupler is designed in this work for decouple a nonlinear MIMO system with two inputs and two outputs. The weights between hidden and output layer are modified online, using an adaptive law in real time. The adaptive law is developed by Lyapunov s Method. A decoupling adaptive controller uses the errors between system outputs and model outputs, and filtered outputs of the system to produce control signals. The RBF network forces each outputs of generator to behave like reference model. When the RBF approaches adequately control signals, the system decoupling is achieved. A mathematical proof and analysis are showed. Simulations are presented to show the performance and robustness of the RBF network

Sistema de navegação para robôs móveis autônomos

The main task and one of the major mobile robotics problems is its navigation process. Conceptualy, this process means drive the robot from an initial position and orientation to a goal position and orientation, along an admissible path respecting the temporal and velocity constraints. This task must be accomplished by some subtasks like robot localization in the workspace, admissible path planning, trajectory generation and motion control. Moreover, autonomous wheeled mobile robots have kinematics constraints, also called nonholonomic constraints, that impose the robot can not move everywhere freely in its workspace, reducing the number of feasible paths between two distinct positions. This work mainly approaches the path planning and trajectory generation problems applied to wheeled mobile robots acting on a robot soccer environment. The major dificulty in this process is to find a smooth function that respects the imposed robot kinematic constraints. This work proposes a path generation strategy based on parametric polynomials of third degree for the 'x' and 'y' axis. The 'theta' orientation is derived from the 'y' and 'x' relations in such a way that the generated path respects the kinematic constraint. To execute the trajectory, this work also shows a simple control strategy acting on the robot linear and angular velocities

Controle fuzzy espacialmente diferenciado para um sistema de irrigação

Traditional irrigation projects do not locally determine the water availability in the soil. Then, irregular irrigation cycles may occur: some with insufficient amount that leads to water deficit, other with excessive watering that causes lack of oxygen in plants. Due to the nonlinear nature of this problem and the multivariable context of irrigation processes, fuzzy logic is suggested to replace commercial ON-OFF irrigation system with predefined timing. Other limitation of commercial solutions is that irrigation processes either consider the different watering needs throughout plant growth cycles or the climate changes. In order to fulfill location based agricultural needs, it is indicated to monitor environmental data using wireless sensors connected to an intelligent control system. This is more evident in applications as precision agriculture. This work presents the theoretical and experimental development of a fuzzy system to implement a spatially differentiated control of an irrigation system, based on soil moisture measurement with wireless sensor nodes. The control system architecture is modular: a fuzzy supervisor determines the soil moisture set point of each sensor node area (according to the soil-plant set) and another fuzzy system, embedded in the sensor node, does the local control and actuates in the irrigation system. The fuzzy control system was simulated with SIMULINK® programming tool and was experimentally built embedded in mobile device SunSPOTTM operating in ZigBee. Controller models were designed and evaluated in different combinations of input variables and inference rules base

Aspectos anatômicos do olho e neuroquímicos da retina do mocó (Kerodon rupestris)

The visual system is an important link between the animal and the environment, com profound influences on the habits and lifestyle in various habitats. Adaptive mechanismsto the temporal niche are present in the visual system of many vertebrates, involving changins in ocular dimensios and design, retinal cell distribution and organization of neurochemical circuits related to the retinal resolution or sensitivity. The sensory system of the eye is represented by the retina, whose organization is responsible by receipty, initial analysis, and transmission of the information to the brain. The knowledge of the position of the eyes in the head and the distribution of retinal cells allow to identify adaptive aspects of each species to its visual field, which is characteristic to the ecological niche it occupies. In this research, we study eye anatomical characteristics and retina neurochemical features of the rock cavy (Kerodon rupestris), a tipical Brazilian rodent from the suborder Hystricomorpha, family Caviidae. The rock cavy has lateral eyes well constitute bony orbit and well differentiated extrinsic muscle. The study of the descriptive and morphometric anatomy of the showed mean values of axial diameter 10.7±0,5mm and equatorial diameter 11.6±0.7mm. The pupil is slit shaped and the lens has mean axial diameter 5.4±0.03 mm, corresponding to ~45% of the axial diameter of the eye. The posterior nodal distance and the retinal magnification factor were estimated at 6.74 mm e 118 μm/grau, respectively. Flat mounts were processed for Nissl stain, and the topographic distribution of ganglion cells showed a moderate visual band, just below the optic disc, with higher density in the ventral retina. Retinal vertical sections and flat mounts were processed for immunohistochemistry to visualize tyrosine hydroxilase (TH) and thus two types of TH+ cells were detected. Type 1 cells had strong TH-immunoreactivity, the body cell varied from 120.047 to 269.373 μm2 stratifying in the sublamina 1 of the IPL. Type 2 cells were weakly TH-imunoreactive, had cell body located mostly in the IPL, varying from 54.848 to 177.142 μm2, constituting ~10% of the TH+ cells. Both cell types exhibited similar topographic distribution with higher density found in a horizontal band along of the naso-temporal axis in the dorsal retina. The total population of dopaminergic cells was 2,156±469,4 cells, occupying an average area of 198,164 μm2. The presence of cones and rods was detected by immunohistochemistry in vertical sections and flat mounts. S cones density is around 10 times smaller than L cones, with different degree of spatial organization. Other retinal neuronal populations of the rock cavy were also detected in vertical sections with specific markers. Comparative analysis of the anatomical characteristics of the rock cavy eye 12 suggest that it was designed to acquire higher sensitivity to light, at expense of image sharpness, compatible with a vision at mesopic conditions. Additionally, the distribution of the 2 subtypes of dopaminergic cells in a naso-temporal band in the dorsal retina seems suitable to a gain in sensitivity, coherent with an animal with predominantly crepuscular activity pattern

Arranjos urbanos e subjetivos contemporâneos na invenção de territórios turísticos

We seek consistency empirical and analytical rigor to the concept of touristification in the course of the contemporary arrangements of subjectivity and urbanity stations through a landscape of social (dis)encounters between residents and foreigners living in the capital of Rio Grande do Norte, Natal. In the last three decades the city has become a major destination country for national and international tourism, making tourism an important monitor of choreography in search of synchrony between cities and subjectivities, orchestrated by the cyclical crises and the relentless battle for systemic capitalistic expansion and survival. We proceed with an ethnographic and cartographic inspiration in Ponta Negra, where the waterfront redevelopment in 2000 conducted by the government, influenced the implementation of various establishments, services and practices related to the construction of Natal s major industry hub of tourism and entertainment. We proposed an arch-genealogy of touristification inspared on Michel Foucault analytical perspective, increased by authors in confluence or in different theoretical and methodological approaches, among which stand out Karl Marx, Gilles Deleuze and Felix Guattari, Michael Hardt and Antonio Negri. The reflections that initially turned to the advancement of the sphere of consumerism as the issue capable of articulating the developmental trajectory of the capitalist system and the practice of tourism, promoting some effects (un)desirable in the conflictual dynamics of the condition of the district of Ponta Negra, territory each again (re) produces the designs to meet the consumption by affluent portion of the population and foreign, encountering social exclusion and inclusion differentiated a growing trend. We go forward with an analysis of the "liberation of desire" phenomenal features of the process of producing subjective, providing a breakdown of the recent world s financial crisis initially, but proved social and political crisis also, through a plot derived from the operation of real estate speculation, which Natal is mainly caught through touristification, showing the outlines of a generalized crisis in establishing a new order buoyed by the emergence of a context "biopolitical" since it is a major route that uses the capital to survive and expand, while guiding the process of "strategic beautification" held in Ponta Negra, problematized by us. We conclude by assessing the appropriateness of proposing on further analysis to explore the establishment of a "new social ontology in terms of interference touristification ongoing and the constitution of a "new order" local/global, away from that characterize a system's capitalist overcoming, try to give emphasis in the current stage of the radicalization of a capitalistic utopia