Carlos Machado Ferreira

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

One of the major problems of voltage stability is the reactive power limit of the system. Improving the systems 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.

ESTUDO DE VIABILIDADE ECONÓMICA E ENERGÉTICA DE ILUMINAÇÃO EFICIENTE COM TECNOLOGIA LED

DOI: 10.14684/intertech.13.2014.358-362 The present study aims at analysing the economic viability of using LED lighting systems combined with the already existing electrical installation in a restaurant area in order to achieve adequate energy efficiency. More and more LED installations are being used in new buildings as well as in renovations of buildings already being used. The type of activity together with the lighting specifications for the restaurant and food sector, the architecture of the location and even the specific requirements put forward by the owner make this type of building a desired target of analysis to achieve energy efficiency. This study will analyse the already existing equipment and the possibility of its replacement by LEDs using a study of energy consumption and the potential of the Dialux lighting calculation program. Index Terms - Dialux, Energetic Efficiency, LEDs, Lighting Design.

A Practical Approach to Lighting Design Course in an Electrical Engineering Programme

Technology has allowed new insights and creativity into the learning and teaching process and also enables to try out in a much more flexible, dynamic way other learning experiences. This constitutes in itself a more engaging role for teachers as well as students helping them to explore and create new areas, opening up, at the same time, new perspectives into the process and maximizing the availability and use of the current tools which the same technology provides. The facilitation in the investigation work development of projects renders the learning and teaching activities really appealing, allowing at the same time levels of effectiveness in this extremely modern and global era. This study integrates technology in the learning process and evaluation of its various outcomes. This case study describes the experience of two teachers with their class along a semester using computer aided technology for instruction and assessment. The task involved the lighting design of monuments with the purpose of attracting the on lookersâ?? attention, enhancing the beauty and attributes of the facade of monuments or buildings considered relevant or of public interest. An approach of reinforcement learning applied to the historical monuments light configurations will be described.