Page 1. A GUI Client for Video Conference based on C++, Cross-Platform, Feature-Enhanced and Mult... more Page 1. A GUI Client for Video Conference based on C++, Cross-Platform, Feature-Enhanced and Multiple-User Sergio B. Villas-Boas1, Lisandro Lovisolo2 1-Escola Politécnica DEL / UFRJ, 2 - DETEL FEN UERJ sbvb@poli.ufrj.br, lisandro@uerj.br ...
ABSTRACT This work aims to understand the impacts of Short Duration Voltage Variations (SDVV) in ... more ABSTRACT This work aims to understand the impacts of Short Duration Voltage Variations (SDVV) in the supply of electricity, that is in the delivery network. A database for the diagnosis of SDVV faults was obtained through simulations of a radial feeder through software PSCAD/EMTDC. The databases is used for benchmark for different approaches for guessing the origin of the fault. It is assumed that the operation is monitoring the voltage and current waveforms at the feeding substation as well as in some other point of the feeder. For detecting the fault these waveforms are applied into a Phase-Locked Loop (PLL), which estimates the frequency, phase angle and amplitude of the voltage and current waveforms. These data feed two artificial neural networks: one to identify the fault and another to locate the origin of it in the SDVV. The technique investigated here applies to three phase feeders with unbalanced loads. The performance of the proposed technique was satisfactory and demonstrates its feasibility to obtain the relevant knowledge for the classification and location of short circuits
ABSTRACT In this work, a multihop Wireless Sensor Network (WSN) is employed to monitor a field, m... more ABSTRACT In this work, a multihop Wireless Sensor Network (WSN) is employed to monitor a field, modeled as a process s(x, y, t). In order to extend the lifetime of the network, we propose two algorithms for energy-efficient reconstruction of the monitored process. The reconstruction of the process is done in sink node, with samples that it receives from each sensor node. Both algorithms explore the variation rate of the field to manage the necessity of communication by sensor nodes, aiming at reducing the amount of transmissions. Furthermore, nodes can sleep between transmissions to save energy. Simulations are done, and results show a significant increase in the network lifetime, compared to a WSN without any energy saving method. The algorithms are evaluated with respect to the reconstruction error of the field being sensed and network lifetime increase.
2009 35th Annual Conference of IEEE Industrial Electronics, 2009
This paper discusses a new PLL (Phase-Locked-Loop) approach for detection of the fundamental posi... more This paper discusses a new PLL (Phase-Locked-Loop) approach for detection of the fundamental positive-sequence component of three-phase systems. Details about this three-phase PLL structure are provided. The positive sequence detector presented computes inner-products between the input and a locally generated version of the fundamental frequency. The inner-products are used to estimate the phase-angle, frequency and amplitude of the fundamental component.
In this paper, is proposed a new three-phase synchronization algorithm having a fast dynamic resp... more In this paper, is proposed a new three-phase synchronization algorithm having a fast dynamic response and robust performance under distortion and/or fault conditions. Details on the structure and the digital implementation are provided. In order to validate the effectiveness of the three-phase phase-locked loop (PLL) algorithm, simulations using PSCAD/EMTDC are presented, under conditions that are similar to the ones encountered
Page 1. A GUI Client for Video Conference based on C++, Cross-Platform, Feature-Enhanced and Mult... more Page 1. A GUI Client for Video Conference based on C++, Cross-Platform, Feature-Enhanced and Multiple-User Sergio B. Villas-Boas1, Lisandro Lovisolo2 1-Escola Politécnica DEL / UFRJ, 2 - DETEL FEN UERJ sbvb@poli.ufrj.br, lisandro@uerj.br ...
ABSTRACT This work aims to understand the impacts of Short Duration Voltage Variations (SDVV) in ... more ABSTRACT This work aims to understand the impacts of Short Duration Voltage Variations (SDVV) in the supply of electricity, that is in the delivery network. A database for the diagnosis of SDVV faults was obtained through simulations of a radial feeder through software PSCAD/EMTDC. The databases is used for benchmark for different approaches for guessing the origin of the fault. It is assumed that the operation is monitoring the voltage and current waveforms at the feeding substation as well as in some other point of the feeder. For detecting the fault these waveforms are applied into a Phase-Locked Loop (PLL), which estimates the frequency, phase angle and amplitude of the voltage and current waveforms. These data feed two artificial neural networks: one to identify the fault and another to locate the origin of it in the SDVV. The technique investigated here applies to three phase feeders with unbalanced loads. The performance of the proposed technique was satisfactory and demonstrates its feasibility to obtain the relevant knowledge for the classification and location of short circuits
ABSTRACT In this work, a multihop Wireless Sensor Network (WSN) is employed to monitor a field, m... more ABSTRACT In this work, a multihop Wireless Sensor Network (WSN) is employed to monitor a field, modeled as a process s(x, y, t). In order to extend the lifetime of the network, we propose two algorithms for energy-efficient reconstruction of the monitored process. The reconstruction of the process is done in sink node, with samples that it receives from each sensor node. Both algorithms explore the variation rate of the field to manage the necessity of communication by sensor nodes, aiming at reducing the amount of transmissions. Furthermore, nodes can sleep between transmissions to save energy. Simulations are done, and results show a significant increase in the network lifetime, compared to a WSN without any energy saving method. The algorithms are evaluated with respect to the reconstruction error of the field being sensed and network lifetime increase.
2009 35th Annual Conference of IEEE Industrial Electronics, 2009
This paper discusses a new PLL (Phase-Locked-Loop) approach for detection of the fundamental posi... more This paper discusses a new PLL (Phase-Locked-Loop) approach for detection of the fundamental positive-sequence component of three-phase systems. Details about this three-phase PLL structure are provided. The positive sequence detector presented computes inner-products between the input and a locally generated version of the fundamental frequency. The inner-products are used to estimate the phase-angle, frequency and amplitude of the fundamental component.
In this paper, is proposed a new three-phase synchronization algorithm having a fast dynamic resp... more In this paper, is proposed a new three-phase synchronization algorithm having a fast dynamic response and robust performance under distortion and/or fault conditions. Details on the structure and the digital implementation are provided. In order to validate the effectiveness of the three-phase phase-locked loop (PLL) algorithm, simulations using PSCAD/EMTDC are presented, under conditions that are similar to the ones encountered
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