Abstract
In the last years the importance of the security analysis has been increasing, due to economical and environment constrains. The operation of an electrical power system is a complex task due to the high degree of uncertainty and the large number of parameters involved. This paper is devoted to the presentation of an efficient steady-state contingency classification using the Rough Set Theory. The developed technique produces a classification of the system operating in four possible states. The powerful methodology developed was applied to a test power network in four different scenarios. The numerical results were compared and analysed in order to obtained important conclusions that provide a valuable contribution to the understanding of the power system security problem.

Abstract

Abstract
Nowadays, the large penetration of wind power generation poses new challenges for the dynamic voltage stability analysis of an electric power system. In this paper is studied the influence of the reactive power management for wind power plants in the dynamic voltage stability of an electric power network under a fault condition, considering two different Doubly-Fed Induction Generators (DFIG) models. The simulation results were obtained using the EUROSTAG software package.

Abstract
In this paper it is proposed a technique to identify the relevant neighbouring electric power systems using the Horizontal Network scheme. The developed methodology was applied to study the IEEE 118 test power network and the Iberian systems. All simulations were performed using the computational software package PSS®E developed by the Siemens/PTI. From the simulation results, some conclusions that provide a valuable contribution to the understanding of the impact of the cross-border interconnections between the countries will be pointed out.

Abstract
This paper presents a new method for the detection of the point of collapse and a new index for the definition of the distance of the voltage collapse point. Performance index to detect and predict stability problems such as the voltage collapse have been a permanent concern for researchers and technical staff in power systems operation. This index can be used on-line or off-line to help operators determine how close the system is to a possible collapse and is a useful analysis tool for planning in power systems too. Numerical experiments using standard IEEE 14 and 57 bus systems show that the proposed method can compute the voltage collapse point using several different scenery of load increase or line outages. The methodology proposed may be easily implemented in any power flow program.

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 a part. 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 be seen as a benefit for Electrical Engineering programme where educators strive for improved teaching and learning. ©2009 IEEE.