Search results for "R measurement"
showing 10 items of 111 documents
A self-synchronizing instrument for harmonic sources detection in power systems
2004
The deregulation of energy markets holds out new prospects for contract between customers and utilities, in which the price of energy can depend on voltage quality and load characteristics, as well as on the responsibility for disturbances caused to supply voltage in power systems. In this context, harmonic sources detection is one of the main problems, because of equipment sensibility and the proliferation of loads which absorb non-sinusoidal currents. In this paper the authors present a new instrument based on a time domain method for the detection of harmonic active powers in three-phase systems, which can be usefully applied even in the presence of unbalance or asymmetry. The amplitude …
Polluting loads detection in power systems: a decision-making strategy based on nonactive power measurements
2010
In this paper a novel decision-making strategy is proposed for the detection of polluting loads in three-phase power systems. It makes use of simple indices, which are expressed as a function of some nonactive power quantities, previously proposed by the authors and derived from the approach of the IEEE Std. 1459–2000. The decision-making rules for the proposed strategy are presented and discussed, by means of some simulation tests.
A time domain strategy for the measurement of IEEE Standard 1459-2000 power quantities in nonsinusoidal three-phase and single-phase systems
2008
This paper describes a time domain technique for the detection of fundamental and harmonic components of voltages and currents, which is able to evaluate all the quantities required by IEEE standard 1459-2000. The technique does not require any spectral analysis to separate the fundamental positive-sequence components from harmonic, negative-sequence and zero-sequence ones. In the paper the development of the proposed technique is presented for three-phase systems, both three-wires and four-wires, as well as for single-phase systems. The implementation of the proposed technique on a PC-based instrument is also described and experimental results are presented. Finally, accuracy specification…
A Time-Domain Approach Based on the IEEE Std 1459-2000 for the detection of Loads Producing Harmonic Distortion
2008
This paper presents a novel strategy for the detection of harmonic sources in power systems for both the single-phase and the three-phase systems. It is based on the IEEE Std. 1459-2000 approach and it is based only on the separation of the fundamental components from the harmonic content of voltage and current. The proposed strategy do not require any spectral analysis of voltages and currents and it can be entirely implemented in the time domain. In the paper, the formulation of the novel approach is given and some simulation results are presented.
Disturbing loads identification in power systems: a single-point time-domain method based on IEEE 1459-2000
2009
This paper presents a single-point method for the identification of prevailing disturbing loads in power systems for both single-phase and three-phase applications downstream or upstream from the metering section. It is based on the simultaneous measurement of three nonactive power quantities, which are based on the IEEE Std. 1459-2000 approach. The proposed method is only based on the separation of the fundamental components from the harmonic content of voltage and current; thus, it does not require any spectral analysis of the voltages and current. In this paper, the formulation of the proposed method and its time-domain implementation are described; moreover, some simulation results are …
First Retrievals of ASCAT-IB VOD (Vegetation Optical Depth) at Global Scale
2021
Global and long-term vegetation optical depth (VOD) dataset are very useful to monitor the dynamics of the vegetation features, climate and environmental changes. In this study, the radar-based global ASCAT (Advanced SCATterometer) IB (INRAE-BORDEAUX) VOD was retrieved using a model which was recently calibrated over Africa. In order to assess the performance of IB VOD, the Saatchi biomass and three other VOD datasets (ASCAT V16, AMSR2 LPRM V5 and VODCA LPRM V6) derived from C-band observations were used in the comparison. The preliminary results show that IB VOD has a promising ability to predict biomass $(\mathrm{R}=0.74,\ \text{RMSE} =44.82\ \text{Mg}\ \text{ha}^{-1})$ , which is better …
Study of optical absorbance and MR relaxation of Fricke xylenol orange gel dosimeters
2017
Abstract Studies on the optical absorbance spectra of Fricke xylenol orange gel dosimeters were performed, in the wavelength range from 300 nm to 800 nm, in order to highlight some particular characteristics that can affect the achievable precision. The spectra are different mainly due to the different types of xylenol orange that was used and to a lower extent due to the different gelling agents (agarose or gelatine). The characteristic of variation of absorbance spectra versus dose, however, are similar in the various cases and can explain some peculiarities, as apparent effects of dose threshold. Changes of spectral shapes appear over the time after irradiation. Magnetic resonance measur…
"Table 8" of "Determination of $alpha_{s}$ in second order {QCD} from hadronic $Z$ decays"
1992
The differential 2-jet rate D2 as a function of YCUT.
A Self-powered Ambient Light Power Measurement Platform with Time-domain Readout
2021
Internet of Things (IoT) provides more and more adequate infrastructures for many applications and advanced services. This scenario promotes the ability to satisfy the growing demand for innovative measuring systems, increasingly popular consisting of intelligent nodes, totally wireless, easy to install, and that requires the least possible maintenance. In this context, this paper aims to contribute to state of the art with an energy-autonomous and battery-free measurement platform designed to measure the ambient light power when its level exceeds the sensitivity threshold. The measurement platform utilizes a single transducer to scavenge energy and concurrently measure the ambient light in…
The Influence of Fruit Ripening Stage at Harvest and Storage Temperature on ‘Bianca di Bivona’ White Flesh Peaches
2015
‘Bianca di Bivona’ is a white-flesh peach cultivar, which ripens during the last week of July and the first of August. Its fruit are known because of their distinct flavor and aroma, which make them highly accepted, particularly in the local markets. However, nothing is known about their postharvest physiology and storage conditions. In order to investigate the effect of: (a) fruit ripening stage at harvest and, (b) storage temperatures, ‘Bianca di Bivona’ peaches were picked at mature-green, (60.0±1.3 N), and ripe stage (30.7 ± 2.1 N) determined by flesh firmness, and then stored at 0°C and 5°C (90% RH). Flesh firmness, total soluble solids, titratable acidity, weight loss and DA index, me…