Richard Pirret, P.E., Jeff Gust
A Phasor Measurement Unit (PMU) is an electronic device that enables real-time computer control to protect the stability and reliability of a power grid. Using GPS-derived timing, the PMU synchronously captures voltage and current phase vectors to create SynchroPhasor data. Synchronous data from multiple PMUs are forwarded to a common point where analysis, control, and protection may be accomplished. Real-world application of PMUs has revealed a need for uniform performance across the various manufacturers of PMUs. Fluke Calibration, under a grant from NIST, is developing an automated system...
XX IMEKO World Congress
· TC4
· 2012
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Jalen Štremfelj, Dušan Agrež,
This paper describes the possibility of estimating the apparent power of a signal component using the interpolation of the products of amplitude discrete Fourier transform (DFT) coefficients. As with energy-based approach for the amplitude square estimation of the onechannel signal, the apparent power in the two-channel case can be estimated with the multiplied amplitude DFT coefficients around the component peak and a suitable interpolation algorithm. The use of the Hann window with well known frequency spectrum and the largest local amplitude DFT coefficients give lower systematic errors...
XX IMEKO World Congress
· TC4
· 2012
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Janusz Mindykowski, Xu Xiaoyan, Tomasz Tarasiuk
The paper deals with measurement and control aspects of active power filtering in ship systems. A main focus of the paper is concentrated on improvement of harmonic current measurement algorithms based on ip-iq method with application of LPF module and, alternatively, on ip-iq method with application of mean value module.
XX IMEKO World Congress
· TC4
· 2012
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Pedro M. Ramos, Fernando M. Janeiro
This paper describes the recent improvements in the use of gene expression programming and genetic algorithms in impedance spectroscopy, namely in sensor modelling. Insight is given in the inner workings of the gene expression programming while highlighting the proposed improvements. The performance of the improved algorithm is also analyzed. It is further validated by the successful application to measurements of a real sensor.
XX IMEKO World Congress
· TC4
· 2012
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Vukan Ogrizovic, Jadranka Marendic, Snežana Renovica, Siniša Delcev, Jelena Gucevic
GPS receivers are often used in time-keeping applications, due to their availability, low price and high accuracy. We made a research in order to test the capability of the GPS receiver to deliver a time-keeping accuracy needed for the time-critical applications, such as astrometry measurements, when a microsecond or even better level of accuracy is needed in real-time. We tested a geodetic class GPS receiver against a rubidium standard, over a 24 hours period. In the overall view, we obtained the accuracy that corresponds to the nominal values. However, we experienced outliers with the...
XX IMEKO World Congress
· TC4
· 2012
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A. Mariscotti
The problem of the evaluation of the interference to signalling track circuits is considered and the specifications appearing in the recently issued European standard discussed. A broad class of track circuits is simulated by means of a band-pass filter and the focus is on the uncertainty related to its implementation.
XX IMEKO World Congress
· TC4
· 2012
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A. Lopes Ribeiro, H. Geirinhas Ramos, D. Pasadas, T. Rocha
This paper describes the usage of a planar excitation coil in a nondestructive testing experiment, using the eddy current method under sinusoidal excitation. After scanning a rectangular area on the metallic surface of the specimen under test, the probe signals obtained by a giant magneto-resistor sensor, were displayed in the form of a 2D representation. To determine the geometric form of the defects inside an aluminum plate, an inversion algorithm was tested. The algorithm is based on a kernel method. It uses the Discrete Fourier Transform (DFT) and Tikhonov regularization to obtain the...
XX IMEKO World Congress
· TC4
· 2012
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Mussa Bshara, Umut Orguner, Fredrik Gustafsson, Leo Van Biesen
The global positioning system (GPS) is a Global Navigation Satellite System (GNSS) uses a constellation of between 24 and 32 Medium Earth Orbit satellites that transmit precise microwave signals, which enable GPS receivers to determine their current location, the time, and their velocity. Initially, the GPS was developed for military applications, but very quickly became the most used technology in positioning even for end-user applications run by individuals with no technical skills. GPS reading are used also as reference points for many positioning techniques such as the techniques that...
XX IMEKO World Congress
· TC4
· 2012
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E. Pinheiro, O. Postolache, P. Girão,
Capacitive sensing of the electrocardiogram allows inconspicuous monitoring of the most well-known electrophysiological signal. Wheelchair users with cardiac maladies would benefit from ECG unobtrusive monitoring. However, motion and daily life activities impose strong artifacts to the signal acquired. This study aims at the extended capacitive electrocardiogram acquisition with and without movement. To validate the hardware, and discern on its capability to do long-term monitoring, recordings of 5 minutes were made for immobile and moving wheelchair, and compared with the contact ECG...
XX IMEKO World Congress
· TC4
· 2012
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O. Postolache, A. Lopes Ribeiro, H. Geirinhas Ramos
The usage of eddy current probes including single magnetic field sensor represents a common solution for defect detection in conductive specimens but it is a time consuming procedure when large surface specimens are tested. In order to speed-up the nondestructive testing procedure, eddy current probes including a single excitation coil and an array of detection coils represent one of the solutions to reduce the NDT times but mainly detects the surface defects. Deep defects require different sensing elements such as GMRs. In this work an optimized uniform eddy current probe architecture...
XX IMEKO World Congress
· TC4
· 2012
· Download