Raul Vitor Arantes Monteiro

Comparative Study of TACS/DBM and MODELS of ATP-EMTP Applied to Power Systems Computer Simulation

The ATP-EMTP has become a reference program for electromagnetic transients computer simulations. Due to the contributions of its officers users groups spread around the world, several improvements were made and additional resources have been developed to facilitate and expand its application. Tools, like ATPDraw, PlotXY, TACS, DBM and MODELS, can drive and enable excelent research studies which may result in internationally renowned scientific papers in the field of Electrical Systems. It is then presented in this paper an additional user guide for these tools with procedures tested in practice and often not covered by official manuals, combined with an analysis of the use of TACS/DBM and MODELS through the computational implementation of a speed governor. The purpose is to identify the potentiality as well as the advantages and disadvantages of TACS/DBM and MODELS. Thus, any user interested in the correct and effective use of these tools may determine the one most suitable to accomplish the computer simulation.

Three ‑ Phase Analysis of Active Losses on Conventional and Compact Distribution Networks

This study aims to analyze the performance under distribution networks, technically comparing the so called conventional distribution network (with bare cables) with those called compact distribution network (with covered cables). In old distribution lines bare cables has been used due the fact that its installation cost is cheaper than the covered ones. But nowadays almost of the distribution companies started to study the feasibility of the installation of compact distribution lines because of its benefits regarding maintenance and reduction of outages. Therefore, this research aims to analyze the technical losses of distribution compact networks when compared to the conventional distribution networks. For this purpose, electrical conductors have been modelled using ATP software and an algorithm for three-phase power flow calculation has been performed by the Newton - Raphson method, developed in MATLAB software. Three different topologies of distribution networks have been tested. Finally, with the simulation results it is concluded that the topology with the compact distribution networks configuration obtained a better performance among others.

Performance Analysis of Neural Network Training Algorithms and Support Vector Machine for Power Generation Forecast of Photovoltaic Panel

Current energy policies are encouraging the connection of power generation based on low-polluting technologies, mainly those using renewable sources to distribution networks. The photovoltaic (PV) systems have experienced a great growth around the word in last years. Hence, it becomes increasingly important to understand technical challenges, facing high penetration of PV systems at the grid, especially considering the effects of intermittence of this source on the power quality, reliability and stability of the electric distribution system. In another hand, the connections of distributed generators, by PV panels, changes voltage profile at low voltage power systems. This fact can affect the distribution networks on which they are attached causing overvoltage, undervoltage, frequency oscillations and changes in protection design. In order to predict these disturbs, because of this PV penetration, this article aims to analyze seven training algorithms used in artificial neural networks for temporal prediction of the generated active power and thus the state of the distribution network in which these microgenerators are connected and, then compare its best results with the Support Vector Machine (SVM) technique. As a result it was concluded that 3 algorithms are suitable for this type of analysis with the best performance among the seven analyzed was the Bayesian Regularization and that Artificial Neural Networks are more suitable for this problem than the SVM.

Features of Present Computer Tools for Load Flow Calculation and Experience Acquired with the Improvement of UFUFlow Program

The use of computer simulations for educational purposes helps students assimilate more easily several theoretical concepts. As in other areas, for teaching and research in energy systems, it is available a wide range of simulation programs. Commercial programs are known to be computationally efficient, however, they are sealed, ie, do not allow modification in the source code or adding new algorithms. Because of this, many tools are developed in academics environmental, most with open source and typically designed for a specific aspect of the electrical system analysis. This is the case of UFUFlow program used to calculate the load flow, developed and used within the Faculty of Electrical Engineering, in Federal University of Uberlândia (FEELT/UFU). Therefore, this paper presents the main computer methods and programs available for the calculation and implementation of load flow algorithm which can assist students or researchers to choose the best tool that meet their needs. Additionally, the improvements performed at UFUFlow, together with the tested and updated information provided here, can be used to encourage them to develop their own program.

Computational and mathematical modeling of a buck driver type of a tubular led lamp

The search for the reduction of energy consumption has encouraged the development of more efficient electrical equipment. In this context are inserted the LED (lighting emitting diode) lamps that since its discovery has been enhanced for different lighting applications, such as interior lighting that uses the so-called Power LEDs in the arrangements of tubular LED lamps. With its bulk insert in the lighting market, become indispensable studies related to these lamps with regard to power quality, lighting quality, energy efficiency and economic feasibility. This paper intends to model mathematically a driver with Buck type converter, as well as its input and output filters, used to drive LED tube lamps, models it computationally by ATP - EMTP software validating this model mathematical and computational through the sized filters behaviour and through power quality experimental analysis of the lamp.

Performance Analysis of Distributed Synchronous Generators with Controllers Equipped with Switchable Operating Modes

Synchronous generators of industrial plants with cogeneration typically operate in parallel with the main utility grid. These machines are usually equipped with excitation controllers operating in constant power factor mode, and speed controllers working in droop mode. While such control techniques are well suited for steady state operation condition, on the other hand, they prevent the generators to act in a favorable way in response to any disturbance that may lead the electrical power system (utility and industry) to instability. This work aims to evaluate the performance of distributed generators with proper switchable controller operation modes using the ATP (Alternative Transients Program) to perform the computer simulations. In simulated cases, the speed controller automatically switches to the isochronous mode if the industrial system loses connection to the main grid. Besides, the excitation controller also automatically changes to the voltage regulator mode for not only this type of occurrence, but also when voltage sags due to power system overloads take place. The results show that the desirable performance of synchronous generators is achieved, as to voltage and rotor stability, when an expanded strategy for their controller operating modes is adopted.