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Publications

Publications by CPES

2014

Constraints and Requirements in Designing an e-learning Environment

Authors
Martins, MJM; Barbosa, FPM; Ferreira, CM; Valdez, MT;

Publication
2014 25TH ANNUAL CONFERENCE EAEEIE (EAEEIE)

Abstract
Nowadays, education extends beyond the field of formal education delivered in universities and colleges, and is increasingly based on new technological developments. Long Life Learning (LLL) is a fundamental tool in today's world in order to remain competitive in the market. The ease of access to the Internet and computer technologies has turned into a new field for developing applications which can be distributed worldwide in an almost instantaneous manner, but must be appropriately designed in order to achieve their goals. Quality e-learning courseware requires several aspects to be covered in order to achieve its purposes. These include a thorough knowledge of the content as well as methods of delivery and learning theory. These requirements were taken into account in the development of a virtual-lab environment, named VEMA, developed by one of the authors and used in the Bachelor and Master's classes.

2014

Collaborative Projects Involving Industry and Academia to Enhance Electrical Engineering Education: The Perspective of three Portuguese Higher Education Institutions at the Master Degree Level

Authors
Martins, MJ; Lopes, F; Fonseca, I; Machado Ferreira, CM; Maciel Barbosa, FM;

Publication
2014 25TH ANNUAL CONFERENCE EAEEIE (EAEEIE)

Abstract
In this paper, Electrical Engineering Education at the Master level is presented through three perspectives of collaborative projects involving industry and academia. The presented perspectives originate from three Portuguese Higher Education Institutions representing the University, Military Academy and Polytechnic School viewpoints. Throughout the presented projects, an increasing student motivation was observed, driven by the practical experience provided through the industrial sector approach. This cooperation also generates opportunities to develop new perspectives and ideas for follow-on projects as well as innovative academic publications.

2014

Comparative Study of STATCOM and SVC Performance on Dynamic Voltage Collapse of an Electric Power System with Wind Generation

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

Publication
IEEE LATIN AMERICA TRANSACTIONS

Abstract
One of the major problems of voltage stability is the reactive power limit of the system. Improving the system's reactive power handling capacity via Flexible AC transmission System (FACTS) devices is a solution for prevention of voltage instability. In this paper it is studied the influence of Static Synchronous Compensators (STATCOM) and Static Var Compensators (SVC) in dynamic Voltage Stability during Low Voltage Ride Through (LVRT), in wind farms. The wind turbines are equipped with pitch control coupled with a Fixed Speed Induction Generator (FSIG). Due to the nature of asynchronous operation, system voltage instability of wind farms based on FSIG is largely caused by the excessive reactive power absorption by FSIG after a fault due to the large rotor slip gained during fault. Wind farm models based on FSIG and equipped with either STATCOM or SVC are developed in EUROSTAG. The Automatic Voltage Regulators (AVR) of the generating units and the turbine speed governors were modeled in detail. Different load models were used and the Under Load Tap Changers (ULTC) were also taken into account. Finally, some conclusions that provide a better understanding of the dynamic voltage stability of a system with FSIG model during LVRT, using various capacities of STATCOM and SVC are pointed out.

2014

Analysis of an incomplete information system using the rough set theory

Authors
Faustino Agreira, CI; Travassos Valdez, MM; Machado Ferreira, CM; Maciel Barbosa, FP;

Publication
Mathematical Methods in Engineering

Abstract
In this paper it is applied a Rough Setapproach that takes into account an incomplete information system to study the steady-state security of an electric power system. The Rough Set Theory has been conceived as a tool to conceptualize, organize and analyze various types of data, in particular, to deal with inexact, uncertainor vague knowledge. The knowledge acquisition process is a complex task, since the experts have difficulty to explain how to solve a specified problem. So, an incomplete set of relevant information may arise. The study presents a systematicapproach to transform examples in a reduced set of rules. These rules can be used successfully to avoid security problems and provides a deeper insight into the influence of parameters on the steady-state system performance. © Springer Science+Business Media Dordrecht 2014.

2014

Maintenance Planning in Wind Farms with Allocation of Teams Using Genetic Algorithms

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

Publication
IEEE LATIN AMERICA TRANSACTIONS

Abstract
Renewable energy is essential for global sustainability. Wind power gave a great contribution to this energy paradigm. The paper describes a maintenance management system for inshore and offshore wind farms, as well as a method to schedule maintenance using genetic algorithms. Under this subject there exists a sub-problem that concerns with the determination of the cheapest path between two points. The paper compares the performance of three methods: genetic algorithms, Dijkstra's algorithm and ant optimization algorithm to the determination of the cheapest path between different wind parks for maintenance.

2014

Identifying Benefits Between the Integration of Electric Vehicles and Renewable Power Usage

Authors
Costa, IC; Rosa, M; Carvalho, L; Bremermann, L; Iria, J;

Publication
2014 IEEE 8TH INTERNATIONAL POWER ENGINEERING AND OPTIMIZATION CONFERENCE (PEOCO)

Abstract
The impact of large-scale Electric Vehicles (EVs) deployment in electric power systems is a current issue under study by the scientific community. The integration of this type of electric component requires robust planning solutions to mitigate possible consequences from such integration. This paper explores the quantification of the amount of renewable sources, namely wind and hydro power, which can be safely integrated into power systems in a scenario of a mass integration of EVs. The increase of renewable power in the generation portfolio is analyzed under the framework of generating system adequacy assessment considering several EVs deployment scenarios and an adequate charging strategy. The analysis is carried for the planning configurations of the Portuguese and Spanish generating systems and the results are focused on the potential benefits of EV integration in terms of hydro and wind power usage.

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