Abstract
Nowadays, the large penetration of wind power generation poses new challenges for dynamic voltage stability analysis of an electric power system. The practical importance of dynamic voltage stability analysis is to help in designing and selecting counter-measures in order to avoid voltage collapse and enhance system stability. The impact of wind integration on reactive reserve requirements is a current area of interest for renewable integration studies and power system operators. In this paper is studied a new wind power plant model with reactive power management. The active power and the frequency management are taken into account too. The developed model can be used to represent, in a simplified way, an entire wind farm in order to simulate the dynamic voltage stability of the system, whatever the technology involved in the wind turbine. The system is completely modelled by a single dynamic converter model with appropriate control loops intended to reproduce the overall response of a wind farm for different grid events, such as faults or voltage and reactive power management at the point of common coupling.

Abstract
This paper presents a study were the Rough Set Theory and Data Mining Technique are applied to the electrical power system. The Data Mining technique classifies the system operation in four possible states: normal, alert, emergency (emergency I and emergency II). The states, that correspond to the normal state can be classified as secure and insecure the remaining ones. In this security studies, the overloads in transmition lines and the violation of the voltage limits are used to classify and rank these contingencies. This technique was applied to the 118IEEE busbar test power network and the results obtained are analyzed. Finally, some conclusions that provide a valuable contribution to the understanding of the power system security analysis are pointed out. © 2013, Springer Science+Business Media Dordrecht.

Abstract
This paper analyzes a real case study based on an islanding power grid, where there is wind power curtailment during the grid operation. This curtailment skews the wind power production database creating a huge challenge to the overall power production forecast. Thus, it is presented a solution which has allowed more accurate forecasts in order to improve the renewable production and reduce the fuel consumption in thermal power plants. The proposed filtering approach demonstrated to be a good solution allowing wind power forecasts with less error and net load forecasts with more accuracy.

Abstract
In this paper it is intended to solve an Economical Dispatch (ED) problem with a new tool, named Sensing Cloud Optimization (SCO). It is a technique based on clouds of particles which allow a dynamic change in search space. It has appropriate heuristic characteristic to solve not convex, not differentiable and highly constrained optimisation problems. It is provided with a statistical analysis which determines the cloud's dimension with dynamic adjustments in search space in order to accelerate the convergence and to avoid to get trapped in local minima. Two case studies are presented in which SCO demonstrated good performances reaching lower cost values where compared with other techniques.

Abstract
The constant changes occurring in today's teaching and learning processes provide a continuous improvement in the interaction of information. At the same time, globalization and the need for streamlining time facilitate the development of new methods of imparting knowledge. With the new information technologies, new forms of learning occur adding greater dynamism to the information. This form of learning, which optimizes time and space, is known as distance learning and it is being amply used in many different areas. Distance education presents the advantage of facilitating the teaching and learning processes without face-to-face interaction as knowledge is transmitted, partly or as a whole using technology. In fact, technological innovation has assumed a vital role in education. Looking to achieve more efficiency in carrying out the various activities, the job market constantly requires an investment in new skills and knowledge so that the professionals can operate the equipment and working tools, successfully and with quality. This paper presents a new system of learning a curricular unit of Circuit Theory using desktop virtual reality (VR). The software provides the possibility to understand the relationship between the physical concepts of an electrical circuit, direct or alternating current, through computer simulations and animations. This work was developed to demonstrate how a desktop VR prototype, "Virtual Electric Manual"-VEMA, can be applied to an engineering unit and used to enhance security and resourcefulness in using electrical equipment. Several interactive scenes were developed to illustrate the idea using a measurements and instrumentation laboratory as virtual environment. A range of interactive learning environments are presented: the menu with the first interactive experiment is the simulator of a DC circuit. It allows the student to analyze the setting up of a parallel, or series-parallel resistive circuit series powered by direct current; the second menu, features the simulator of an alternating current circuit and demonstrates how the student can perform the analysis of a circuit with resistors, inductors and capacitors; the third interactive experiment is the simulator of a three-phase alternating current circuit; the fourth menu refers to a study on the transitional phenomena. Finally, the fifth menu is an interactive experiment related to the phenomena of resonance. VEMA offers students the opportunity to understand the processes, helping them to better discern the procedures and trains them to interact with the equipment. The VEMA prototype addresses these issues and highlights the potential benefits of using VR for this purpose. Each experiment will provide technical and scientific knowledge in order to give the student/user adequate information and training in the subject.

Abstract
Higher education has evolved in the last decade with the use of information technology. This change was called distance education, a teaching method in which the student does not need to meet with the teacher on a certain day and time. The student may be either at home or at work and may have no interaction with the other parts, either the teacher or other students. It has allowed the institutions to resolve geographical gaps in order to reach the largest number of students. On the other hand, it paved the way for the "non-traditional" universities oriented for "adult work", in a narrow range of graduation programs, compatible with the current demands from industry. It is also important to mention that distance education is becoming increasingly appropriate for non-academic studies, such as corporate training environments. This paper addresses Circuit Theory systems, more specifically laboratory practices geared towards teaching and learning. The choice was made from observing the needs in the specific context of a measures and instrumentation laboratory, mainly related with access to the means and equipment to carry out laboratory practice. The purpose of the work is the use of virtual experimentation to carry out laboratory practice and also as an alternative tool to meet the needs of access to the means and equipment of the laboratory. In the present case, the basis of the project was the construction of a 3D lab environment (Measures and Instrumentation) where the equipment and the components can be seen and manipulated. The project involves simple electrical schematics, which later can be changed in values, presenting new results, and displays a set of menus and submenus to support experiments. The virtual laboratory can accommodate new devices and scenarios, being adapted to new subjects, such as electric machines and power system analysis of the Electrical Engineering program. This work was developed to demonstrate how a desktop VR prototype, "Virtual Electric Manual" - VEMA, can be applied to an engineering unit and used to enhance security and resourcefulness in using electrical equipment. Several interactive scenes were developed to illustrate the idea using a measurements and instrumentation laboratory as virtual environment. The added value of these various features in the educational context is that they contribute to the construction of new virtual environments, able to benefit the communication between teachers and students and among themselves, thus creating new opportunities for each student to participate more actively in his/her own learning construction process. Rather than being seen as mere information files, these e-learning platforms should be perceived as a means to promote interaction and experimentation through technological resources.