Publications

2009

Groupware: Design, Implementation, and Use, 15th International Workshop, CRIWG 2009, Peso da Régua, Douro, Portugal, September 13-17, 2009. Proceedings

Authors
Carriço, L; Baloian, N; Fonseca, B;

Publication
CRIWG

Abstract

2009

A study on the determination of stochastic reinforcement permeability in constant injection pressure conditions

Authors
Goncalves, PCT; Correia, NC;

Publication
ICCM International Conferences on Composite Materials

Abstract
We report two effects in permeability measurement: the error introduced by assuming constant injection pressure and the evolution of permeability dispersion with volume fraction. For the first, we proposed a simple modelling approach. For the second, our results showed a reduction in the dispersion with higher fibre volume fractions, which we believe is due to the reduction of the variability of the size of the pores of the reinforcement.

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2009

Meta-Learning

Authors
Carrier, CGG; Brazdil, P; Soares, C; Vilalta, R;

Publication
Encyclopedia of Data Warehousing and Mining, Second Edition (4 Volumes)

Abstract

2009

Methods for preventing voltage collapse

Authors
Reis, C; Andrade, A; Maciel Barbosa, FP;

Publication
ELECO 2009 - 6th International Conference on Electrical and Electronics Engineering

Abstract
The condition of voltage stability in a power system can be characterized by the use of voltage stability indices. The voltage stability analyses were conducted on the IEEE 14 and IEEE 57 reliability test system, using several different scenarios of load increase. In this paper, a comparison of the performance of several indices is presented, with satisfactory results. In this paper will also present New Index to Voltage Collapse (NIVCP). NIVCP is a system index and see the all power system.

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2009

Proceedings of the 1st workshop on Linking aspect technology and evolution, PLATE '09, Charlottesville, Virginia, USA, March 3, 2009

Authors
Groher, I; Kellens, A; Schwanninger, C; Adams, B; Hohenstein, U; Aguiar, A; Truyen, E;

Publication
PLATE@AOSD

Abstract

2009

Evolutionary Algorithm EPSO Helping Doubly-Fed Induction Generators in Ride-Through-Fault

Authors
Leite, H; Barros, J; Miranda, V;

Publication
2009 IEEE BUCHAREST POWERTECH, VOLS 1-5

Abstract
A tuning process of the PI (Proportional-Integral) controller gains of a doubly-fed induction generator's (DFIG) rotor side converter is described in this work. The purpose is to tune PI controllers to help the DFIG to survive to network faults, avoiding being tripped-off by under-voltage relays. The ride-through-fault capability of DFIGs improves system reliability and allows them to participate in the control and stabilization of a power system following system disturbances. The robust tuning of the DFIG rotor side converter's PI controllers may avoid undesired disconnections from the grid by, for instance, preventing over-currents in its variable frequency AC/DC/AC converter. This work presents an Evolutionary Particle Swarm Optimization-based (EPSO) approach to this tuning, with the aim of helping to limit the line-to-line voltage dip at the DFIG's terminals after a short-circuit, in order to avoid its tripping-off. The EPSO-based algorithm developed is validated at a typical Portuguese 15 kV Distribution Network with the integration of a DFIG, using the transient electromagnetic software package PSCAD/EMTDC (TM).

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