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Antunes F.A.S.,CEMIG | Ribeiro P.F.,Federal University of Itajuba | Silveira P.M.,UNIFEI
IEEE Power and Energy Society General Meeting | Year: 2015

One of the most challenging proposals about the smart grid concept is the deployment of features that enable a power grid to reconfigure itself, isolating defects and recovering through alternative available routes after disturbances. This ability is known as Self-Healing, a concept most widespread in distribution power systems. In transmission power systems, however, there is a substantially lower amount of research. Some authors says the actual transmission is inherently self-healing since its topology is meshed designed, which ensures redundancy for equipment trips, preventing a load outage. Nevertheless, automatic transmission systems reconfiguration presents high improvement potential in the restoring process, in terms of security and agility. Under this scenario, this paper sets the framework for a self-healing system to perform in the transmission system. In this framework, are considered the main technical requirements, concerns, points of attention and inherent issues of transmission operation process. The Assisted-Healing concept will also be considered for such circumstances in which the Self-Healing is not convenient or not possible to be fully performed. The main aim is support operators to deal better with stressful decisions related to the restoration process after power systems disturbances, reducing assets and load outages periods. © 2015 IEEE. Source

Schettino B.M.,Federal University of Juiz de fora | Duque C.A.,Federal University of Juiz de fora | Silveira P.M.,UNIFEI
IEEE Transactions on Power Delivery | Year: 2016

A new application of the Savitzky-Golay (SG) filters in current-transformer saturation detection is proposed. The ability of the SG filters to handle noisy signals improves the robustness of the detection process in the presence of noise while requiring only low computational effort. © 2016 IEEE. Source

Castanharo J.A.,State University of Rio de Janeiro | Mello I.L.,State University of Rio de Janeiro | De S. Maria L.C.,State University of Rio de Janeiro | Costa M.A.S.,State University of Rio de Janeiro | And 2 more authors.
Polimeros | Year: 2012

Magnetic polymeric microspheres based on styrene (STY), divinylbenzene (DVB), vinyl acetate (VAc) and iron were prepared through suspension and semi-suspension polymerization. An investigation was made of the influence from the concentration of VAc added to the polymerization and the presence of iron on the properties of the polymeric particles. These particles were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTGA), reflection optical microscopy (OM), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Polymeric microspheres with magnetic properties based on styrene, divinylbenzene and vinyl acetate were obtained. These materials showed good control of the spheres morphology and aggregated iron particles throughout the microsphere surface. The greater yield of microspheres was found in the range of 288 μm. They also showed good magnetic properties (from 22.62 to 73.75 emu.g-1) with superparamagnetic behavior and good thermal stability (444 °C). Source

Motta R.S.N.,Engineering University of Itajuba | De Souza L.E.,UNIFEI
Stahl und Eisen | Year: 2010

A new process is described of handling the pulverized coal injection (PCI) into blast furnaces in an energy efficient way, aiming at decreasing the specific consumption of electricity and nitrogen. The process improvement included two new phases in the main coal vessels sequence. The return on investment (ROI) was high as the specific electricity and nitrogen consumption were reduced and the lifetimes of operational valves were increased as well. The process is now operationally more stable when compared to the original design. Source

This study examines the supplier relationship management (SRM) through the approach of Olsen & Ellram in five small and medium enterprises located in the Electronics Valley Cluster, Brazil. It is an exploratory descriptive study with data collection performed through interviews with executives of these five companies. It was possible to conclude that there is a strong need for technology partnerships with suppliers because of the possibility of competitiveness growth associated with supplier technology. However, relationships with suppliers are still incipient and informal, with no support strategies and systems integration. Because of the use of high technology inputs, integration with suppliers presents a great potential to improve the competitiveness of the enterprises in this cluster. However, in order to foster this potential, the cluster and its institutions need to develop incentive policies and joint actions. Source

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