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Publications

Publications by CPES

2009

The main causes of incidents in the portuguese transmission system - Their characterization and how they can be used for risk assessment

Authors
De Almeida, SAB; Pestana, R; Barbosa, FPM;

Publication
2009 6th International Conference on the European Energy Market, EEM 2009

Abstract
This paper aims to characterize accurately each incident main cause, to analyse their occurrence with the intrinsic characteristics of the Portuguese territory, including geographical and meteorological data, and to define the requirements and guidelines to use this information as input for a risk assessment methodology, whose main purpose is to support control room operators in their continuous task.

2009

Load shedding - Coordination between the Portuguese transmission grid and the distribution grid with minimization of loss of distributed generation

Authors
Fernandes, RV; De Almeida, SAB; Maciel Barbosa, FP; Pestana, R;

Publication
2009 IEEE Bucharest PowerTech: Innovative Ideas Toward the Electrical Grid of the Future

Abstract
Nowadays the total sum of Distributed Generation (DG) in the Portuguese Distribution Network (DN) is extremely significant. Previously, load shedding schemes were designed without taking into consideration this type of generation. In this paper, the Portuguese Electrical System is studied through a static analysis using real data, and the new relay parameters to be applied in substations are evaluated, continuously bearing in mind the strict coordination with those of the DN. In order to achieve these purposes, an algorithm was developed to rank possible candidate substation feeders to the load shedding plan, using Ms Excel to process data and perform the calculations. The obtained results show that by using the designed algorithm it is possible to find a systematic process for determining under-frequency relay parameters considering the trade-off between shedding critical consumers and shedding DG. © 2009 IEEE.

2009

INTEGRATING WIND POWER ENERGY INTO ELECTRIC GRIDS AN ENVIRONMENTAL ISSUE

Authors
Barbosa, FM; Farinha, JT; Fonseca, I; Simoes, A; Ferreira, L; Marques, V;

Publication
ENERGY PROBLEMS AND ENVIRONMENTAL ENGINEERING

Abstract
Taking into account that the non renewable recourses are less and less available worldwide we need to use renewable energies to produce electricity. The wind energy is nowadays the most attractive renewable energy, after hydropower, to produce electricity. Wind energy is the renewable energy source that had a higher growing in the last decades and can be considered a hope in future based on clean and sustainable energy. All over the world, energy companies are investing in technologies to make better use of renewable energy to generate electric power. Wind energy is the renewable energy source that had a higher growing in the last decades and can be considered a hope in future based on clean and sustainable energy. Unlike conventional fuels, wind energy is a massive indigenous power source permanently available in virtually every nation in the world. Wind power delivers the energy security benefits of fuel costs, no long term fuel price risk, and avoids the economic and supply risks that can arise with reliance on imported fuels and political dependence on other countries. The problems resulting by the production of electricity using wind power and by the interconnection of wind parks to the grid are discussed in this paper.

2009

BUSES DEGRADATION BASED ON EXPLORATION CONDITIONS

Authors
Simoes, A; Farinha, T; Fonseca, I; Barbosa, FM; Marques, V;

Publication
ENERGY PROBLEMS AND ENVIRONMENTAL ENGINEERING

Abstract
In a world with a global market that is continually increasing, the productivity management plays an important key role to keep the competitiveness. The productivity can be achieved through the availability that can be increased through the adoption of efficient maintenance practices, by focusing the organisations on adequate type of maintenance strategy. Condition Based Maintenance (CBM) uses primarily non destructive testing techniques, as environmental indicators, visual inspection, monitoring functioning variables and performance data. This kind of maintenance replaces tasks of scheduled maintenance by warranted interventions predicted by on-condition limits previously defined. The interventions occur only when the equipments presents abnormal symptoms. The intervals of CBM are determined based on the expected delay to fail and are managed through the frequency by which the predictive interventions have to be done. The technological advances are accepted and applied on CBM systems, which includes improved knowledge of failure mechanisms, advancements in, failure forecasting techniques, monitoring and sensor devices, diagnostic and prognostic software, communication protocols, and computer networking technologies. The measurement precision and sensitivity of the Condition Monitoring (CM) techniques are used because they affect the reaction time available to reduce or eliminate the consequences of the functional failure. CBM maintenance tasks must be applicable under the situation of cost effective improvement, including external costs. The base of development of this paper is supported by an integrated system called SMIT (Terology Integrated Modular System), that permits to manage the maintenance itself, including on-condition maintenance, but it is modular enough to permit to associate new features, namely this last approach, in order to maintain the system up-to-date and, always possible, to anticipate the future.

2009

Dependability and Maintenance: their Interrelation and Importance in Industrial Operations Sustainability

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

Publication
ENERGY PROBLEMS AND ENVIRONMENTAL ENGINEERING

Abstract
In a global world, the survival and sustainability of industrial companies depends on several factors: production continuity; quantity assurance; quality assurance; competitive prices for products; on time production; flexibility; operational safety and environmental safety. To achieve these goals, sustainable industrial operations must rely on dependable systems and equipments. Dependability is defined as "the collective term describing the availability performance of any simple to complex product" [1]. This definition can be extended for industrial operations, to their reliability and maintainability design characteristics. As there are no perfect systems and equipments designs, component degradation and failures will always occur during their life cycle. So to keep their dependability level during the life cycle good maintenance support is essential. In this paper we will discuss the importance of maintenance to achieve the required dependability and sustainability for industrial production processes and how that can be achieved.

2009

PBL Implementation in a Lighting Design Course

Authors
Travassos Valdez, MMT; Faustino Agreira, CIF; Machado Ferreira, CMM; Maciel Barbosa, FPM;

Publication
UPEC: 2009 44TH INTERNATIONAL UNIVERSITIES POWER ENGINEERING CONFERENCE

Abstract
An engineering curriculum requires that its future professionals should be fully prepared to accomplish a variety of tasks involving not only theoretical concepts, but also skills acquired through effective practice. In the Instituto Superior de Engenharia de Coimbra (ISEC), Department of Electrical Engineering, preference was given to apply 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 the Lighting Design course. The students are presented with a virtual scenario, quite similar to the real world, where they are required to perform as they would in a real life situation. The emphasis is given to PBL so that they can learn to become autonomous, skilled and explore their own potential as well as improve team work skills/spirit and that can be applied to a wide range of students and subject matters. PBL is introduced to the students as a 'learn by doing' project. The project incorporates aspects of electrical engineering and computing skills. This study analyses the learning process/techniques that help students deal with the complexity of a Lighting Design Project and assesses its effectiveness and impact on the students. Essentially, it encourages them to be in charge of their education. The benefits of PBL in the Lighting Design course are visible in the improvement of the study and analysis of a Lighting Design project. The method may also bring benefits for Electrical Engineering programmes where educators struggle for improved teaching and learning. The simulation was performed using the Dialux 4.3 software package that runs in Windows Vista or XP environment.

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