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Publications

Publications by Fernando Maciel Barbosa

2010

A Better Environment Through Better Terology

Authors
Farinha, JT; Fonseca, I; Simoes, A; Barbosa, M; Bastos, P; Carvas, A;

Publication
RECENT ADVANCES IN ENERGY AND ENVIRONMENT

Abstract
A better environment can be achieved through the reduced emission of pollutants, the optimization of green energy production and the optimization of maintenance interventions, which is an important contribution in getting equipment functioning as efficiently and effectively as possible and, of no less importance, to minimize the downtime caused by faults. These are the key points presented in this paper, which also emphasizes the very recent contribution of 3D models in aiding fault diagnosis and terology in general. The way to achieve the above-mentioned objectives is through on-condition maintenance in two main fields, wind farms and Diesel engines. In wind farms, maintenance is done through the control of variables, such as vibration signals and the balance of electrical currents. As for Diesel engines, on-condition variables are the emissions of PM10, NO(x), CO, HC and CO(2). However, there are problems in both situations, namely, in the first case, the distance and accessibility of the generators and, in the second case, the problems associated with the fact that the equipment is not static. Another common problem in both situations is the measuring and transmission of the values of the on-condition variables, because, in the case of wind farms, the machine is placed on top of the tower and, in the case of Diesel engines, the vehicles are in operation most of the time and most of the measurements need be made while the vehicles are running. Also, although the two situations seem different, they have many issues in common, such as those above-mentioned, for which we will propose convergent solutions that have an Integrated Modular System for Terology (SMIT - Sistema Modular Integrado de Terologia) as a base platform. In addition, to collect, transmit and manage data, we also propose low-cost hardware devices and open-source software, with time series, Hidden Markov Models and genetic algorithms incorporated into them, to enable the prediction of new maintenance interventions. Another important development that is mentioned, with the objective of achieving a more effective terology system, is the implementation of 3D models to aid fault diagnosis and maintenance interventions in general. All these subjects are treated in this paper in a cohesive and synergistic way in order to achieve more effective terology management with an environmental perspective.

2010

Wind maintenance system using network synchronization techniques based on open-source software

Authors
Fonseca, I; Farinha, JT; Barbosa, FM;

Publication
RECENT ADVANCES IN ENERGY AND ENVIRONMENT

Abstract
The use of open-source software in many institutions and organizations is increasing. However, a balance should be considered between the software cost and the cost of its technical support and reliability. In this article, a maintenance system for wind farms will be presented. It is connected to an information system for maintenance, called SNIFF (Terology Integrated Modular System) as a general base to manage the assets and as a support strategic line to the evolution of this system, which incorporates on-condition maintenance modules, and the support to the research and development done around this theme. The SMIT system is based on a TCP/IP network, using a Linux server running a PostgreSQL database and Apache web server with PHP, and Octave and R software for numerical analysis. Maintenance technicians, chiefs, economic and production management personnel can access SMIT database through SMIT clients for Windows. In addition, this maintenance system for wind systems uses also special low cost hardware for data acquisition on floor level. The hardware uses a distributed TCP/IP network to synchronize SMIT server master clock through Precision Time Protocol. Usually, the manufactures construct, deploy and give the means for the suppliers to perform the wind system's maintenance. This is a very competitive area, where companies tend to hide the development details and implementations. Within this scenario, the development of maintenance management models for multiple wind equipments is important, and will allow countries to be more competitive in a growing market. For on-condition monitoring, the algorithms are based on Support Vector Machines and time series analysis running under Octave and R open-source software's.

2009

Lighting Design Course in an Electrical Engineering Programme Using Problem-Based Learning

Authors
Valdez, MMT; Agreira, CIF; Ferreira, CM; Barbosa, FPM;

Publication
2009 EAEEIE ANNUAL CONFERENCE

Abstract
This study is dedicated to the learning process to help students to deal with the complexity of a Lighting Design Project. In the Department of Electrical Engineering, preference was given to applying methods integrating technology in the learning and then evaluating the outcomes. Problem-based learning (PBL) was used as an instructional strategy of active learning, and adapted for use in Lighting Design course. In cooperative learning, students work together in small groups in an organized way, on a well-ordered activity They are individually responsible for their work,. on the other hand, the work of the group as a whole is also assessed. Teams need to be small enough so that everyone can play apart And the students' work must be clearly defined. By applying PBL it is expected that students work in a cooperative and collaborative learning way, developing positive interdependence, individual accountability, face-to-face promotive interaction, as well as group processing. Students see the potential of the method. PBL addresses many of the concerns of teachers and professional organizations. Above all, it encourages students to be in charge of their education. It emphasizes critical thinking skills, understanding, learning how to learn, and working cooperatively with others. The benefits of PBL in the Lighting Design course are seen in the way students improved the study and analysis of a Lighting Design project. This method can also he seen as a benefit for Electrical Engineering programme where educators strive for improved teaching and learning.

2008

A computer system for predictive maintenance of wind generators

Authors
Fonseca, I; Farinha, T; Barbosa, M;

Publication
PROCEEDINGS OF THE 12TH WSEAS INTERNATIONAL CONFERENCE ON COMPUTERS , PTS 1-3: NEW ASPECTS OF COMPUTERS

Abstract
Wind generators maintenance can be performed in a systematic way because they are built with equipments with known reliability and maintenance parameters known that can be used in the planned maintenance. However, it is possible to increase the reliability of the system so as to rationalize the costs, by developing new management models and new algorithms based on on-line monitoring of several parameters, namely vibrations, electrical variables, among others. It is because of this kind of challenge that the authors are developing new methodologies in the area of wind generators that, as we will demonstrate, can contribute to a better environment. The methodology proposed aims to optimize the cycles of production and, consequently, reduce other kinds of energy production. The new methodologies will be, later, incorporated through new predictive maintenance modules in an integrated maintenance management system called SMIT (Terology Integrated Modular System). The base of SMIT is accessed through a client-server system and a browser system that includes the main modules of a traditional system, as well as a fault diagnosis module, a non-periodic maintenance planning module and a generic on-condition maintenance module, among other innovations. The new features will include, in the case of wind generators, on-line measures and the corresponding on-time treatment, using algorithms based on time-series forecasting.

2008

New approaches on predictive maintenance based on an environmental perspective: The cases of wind generators and diesel engines

Authors
Farinha, T; Fonseca, I; Simoes, A; Barbosa, M; Viegas, J;

Publication
PROCEEDINGS OF THE 12TH WSEAS INTERNATIONAL CONFERENCE ON CIRCUITS: NEW ASPECTS OF CIRCUITS

Abstract
Maintenance management is a subject that, instead of reducing importance with the increase of equipment reliability, it increases its role in the companies and obliges the increase of the level of demand of professionals involved because of the new technical and environmental demands. Sometimes, scientific developments anticipate the company's needs while other times it is the company that challenges science. The maintenance area is an example that offers challenges to both science and companies in order to optimize the performance of equipment and facilities. However, if during the industrial era the maintenance had to respond to industry, nowadays, and in parallel with the increase of equipment performance, the maintenance has the obligation to aid in order to convert technology in becoming more environmentally friendly. It is because of this kind of challenge that the authors are developing new methodologies, almost antagonistic, because of the areas in development, namely diesel engines and wind generators, and as we will demonstrate, areas which are compatible and can contribute to a better environment. In the case of wind generators, the methodology aims to optimize the cycles of production and consequently, reduce the other kinds of energy production. On the other hand, the methodologies for maintenance of diesel engines are based on environmental indicators that can predict the "health state" taking into account restrictions including health human factors among others. The new methodologies will later be incorporated through new predictive maintenance modules in an integrated maintenance management system called SMIT (Terology Integrated Modular System). The SMIT system includes the main modules of a traditional system, as well as a fault diagnosis. a non-periodic maintenance planning and a generic on-condition maintenance module, among other innovations. The new features will include, in the case of wind generators, on-line measures and the corresponding on-time treatment, using algorithms based on time-series forecasting and wireless technology to transmit the signals. In the case of diesel engines, the algorithms are based on Markov chains and hidden Markov chains, with an approach that is offering good results, which proves the validity of the methodology and the innovation itself. It is based on these developments and the new researches mentioned so far that this paper is built upon, and we believe will be a contribution to the maintenance management area.

2005

Influence of the under load tap changers on the dynamic voltage collapse of an electric power system

Authors
Pereira, RMM; Ferreira, CMM; Pinto, JAD; Barbosa, FPM;

Publication
UPEC 2004: 39th International Universitities Power Engineering Conference, Vols 1-3, Conference Proceedings

Abstract
Most power systems are nowadays operated very near to their operating limits due to increase in consumption, while economic and environmental constraints have limited construction of new generation facilities and lines. This paper is devoted to the analysis of the ULTC effect in the dynamic voltage stability of an electric power network. Usually substations are provided with transformers with tap-changers facilities. It was long believed that transformers with tap-changers could eliminate or minimize effectively voltage instabilities. In this study it is shown the influence of the ULTC in the voltage instability for some situations in the analysed power network. It was used the BPA test power network. A severe contingency situation was simulated. The automatic voltage regulators of the generating units and the turbine speed governors will be modelled. The simulation results were obtained using the commercial transient software package EUROSTAG. Finally some conclusions that provide a better understanding of the voltage collapse phenomena are pointed out.

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