Search

Volt/VAR control (VVC) techniques may be used for purposes such as technical loss reduction, voltage profile improvement, and conservation voltage reduction. The advent of distributed energy resources (DERs) at distribution and consumer levels imposes imperative VVC challenges for the distribution network operator. Innovative approaches have been proposed to use the inherent thermal inertia of buildings to provide ancillary services to the grid to tackle the problems posed by increasing trend of volatile DERs. Numerous state-of-the-art VVC strategies utilize traditional VVC devices and smart inverters to deal with voltage violations in active distribution networks (DNs) with increased DER penetration. However, they have not considered the potential service buildings can provide to mitigate this problem. The ability of smart buildings to provide reactive power support to the grid has not been exploited to date. Hitherto, the effect of the modulation of loads’ reactive power consumption on the grid's voltage profile has not been studied. In this article, a distributed model-predictive control strategy for VVC in the DN by utilizing smart buildings is presented. The robustness of this strategy is validated on a modified IEEE 13-bus system.

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.

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.

Currently the projects of rural electricity distribution networks figure as high demand for services for electrical engineering offices. Being the Mato Grosso State one of the largest agricultural producers in Brazil, the demand for these types of services are growing, considering that for the load connections or extensions of consumers it is necessary the development of these projects which are characterized by a very specific process. With increased competition in this kind of Market, that demands more speed and quality, the use of the project management is available as an alternative that is already succeeding in other sectors where it is applied. The focus of this work lies in the development of a structural model of project management of a rural power distribution networks, based on the framework of tools available in the project management, which has as its main reference the PMBOK. This design calls for a eventual study and structuring to implement such practices. The tools applications properly selected according to the needs arising in real projects are suggested and possible impacts arising in their subsequent use are discussed. The selected tools showed a level of satisfactory results, enabling improvements in the process, control and conclusion of such project.

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.

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.

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. Additionaly, 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.

The ATP-EMTP has become a reference program for electromagnetic transients computer simulations. Due to the contributions of its officer's 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.