Realizzazione di un campione di potenza tramite una scheda di acquisizione dati commerciale

Prestazioni metrologiche delle pinze amperometriche in regime distorto

Partial trisomy 9p and partial monosomy 6q resulting from paternal reciprocal translocation 6;9: Overlapping manifestations of characteristic phenotypes from birth to age 4 years

We report on a female infant with partial trisomy 9p (p13.3→pter) and monosomy 6q (q26-qter) resulting from a paternal balanced reciprocal traslocation t(6;9)(q26;p13.3). Both trisomy 9p and monosomy 6q are recognized phenotypes with characteristic patterns of anomalies. This patient is the first reported with a partial deletion 6q and a partial duplication 9p resulting in an overlapping phenotype including intrauterine growth retardation (IUGR), craniofacial and skeletal abnormalities, congenital heart defect, hypotonia and developmental delay. We present the clinical follow-up of this patient from birth to age 4 years: the phenotypic manifestations of trisomy 9p syndrome are mildly expres…

Caratterizzazione e modellizzazione di un sistema di comunicazione power line in media tensione

A time domain approach for IEEE Std 1459-2000 powers measurement in distorted and unbalanced power systems

Behaviour of reactive energy meters in polluted power systems

The reactive energy meters used in electric distribution networks are based on a conventional definition of reactive energy (or power) for sinusoidal voltages and currents, containing only the fundamental frequency component. As a consequence, the performances of reactive energy meters in the presence of harmonic distortion are not tested and their accuracy specifications can be very different from the nominal ones, that are evaluated in sinusoidal conditions. In this paper the authors present a comparative study of the performances of different reactive energy meters, both electromechanical and static, in the presence of harmonic distortion; the study is supported by several simulations an…

Modello di un sistema di comunicazione power line applicato alla rete di media tensione

On the model of MV power line communication system in the case of line to line transmission

Uncertainty evaluation in power measurements with commercial data acquisition boards

The paper deals with the metrological characterization of a digital wattmeter developed by using a personal computer, a shunt, two commercial data acquisition boards and commercial software. The uncertainty of the active power measurements is assessed individually characterizing the voltage channel, the current channel and the phase displacement measurement between the two channels. In particular, the uncertainty on the voltage and current rms measurements is evaluated by using an already proposed approach based on the Monte Carlo method and on the usage of five parameters, while the uncertainty on the phase angle is experimentally estimated. In order to validate the proposed approach for t…

On the calibration of reactive energy meters under non sinusoidal conditions

This paper is focused on the problems related to the calibration of the reactive energy meters on the place of installation of the electricity meter (on-site), using the load of the same electrical system. In the presence of harmonic distortion, the behaviour of the meters can go out of the limits imposed by the theoretical calibration curve depending on the metric used by both reference standard meters and meters under test.

Hypercalciuria and kidney calcifications in terminal 4q deletion syndrome: further evidence for a putative gene on 4q.

We report a newborn girl with a de novo terminal 4q deletion (q31.3 --> qter) and a characteristic phenotype of minor facial anomalies, cleft palate, congenital heart defect, abnormalities of hands and feet, and postnatal onset of growth deficiency. Laboratory studies showed excessive urinary calcium excretion on standard milk formula and on oral calcium load. Blood measurements of parathyroid hormone, calcitonin, bicarbonate, calcium, phosphorus, magnesium, sodium, chlorine, potassium, and urinary measurements of phosphorus, magnesium, sodium, chlorine, potassium were normal for age. At 2 months of life, ultrasonography showed kidney calcifications. Clinical and laboratory data support the…

Nuova procedura di caratterizzazione dei trasformatori di corrente in regime distorto

Characterization of the Magnetic Induction Field produced by Secondary Substations

The aim of this paper is to develop a methodology for measuring the magnetic field distribution around the prefabricated secondary substations in vibrated reinforced concrete, as well as the definition of a methodology to determining the maximum value of magnetic induction produced by the substations in correspondence to nominal current of the transformer. As proposed has been developed in conformity with laws and standards and can be applied to active and passive secondary substations. The experimental validation of the proposed methodology, carried out by a measurements campaign whose results are reported, confirms the validity and returns a versatile and simple tool for the verification …

A New Protection Strategy for Electrical Distribution Systems

In this paper, the authors propose a new protection strategy for electrical Medium Voltage distribution networks, based on a distributed intelligence system composed of a central unit and of many local processing units. The distributed intelligence system can precisely identify and locate faults in suitably limited times. Each local processing unit is composed of a data acquisition system and a data analysis system. The first allows the accurate reconstruction of the fundamental using only 1.5 cycles of under fault transient electrical quantities. The second performs suitably precise on-line fault diagnosis based on the data provided by the data acquisition module. The data acquisition algo…

A PC-based instrument for automatic monitoring and control of a CPVT power plant

A PC-based instrument has been developed for the monitoring and control of a concentrated photovoltaic and thermal (CPVT) power plant. The instrument allows acquiring both electrical and thermal quantities. Moreover it implements the solar tracking algorithm used to optimize the power production.

On the methodologies for the calibration of static electricity meters in the presence of harmonic distortion

This paper is focused on the problems related to the calibration of static electricity meters with nonsinusoidal test waveforms. This is an up-to-date issue since the harmonic distortion levels are ever increasing, especially in low-voltage power systems, and in such conditions the performances of the modern static electricity meters can be negatively affected, depending on the implemented measurement algorithm. Thus it is important to test the meters with nonsinusoidal waveforms. The paper analyzes the problems related to both the choice of the test signals to be used for calibration and the implemented metric, with a particular focus on the reactive energy meters. The analysis is supporte…

DC series arc faults in PV systems. Detection methods and experimental characterization

This work is focused on the arc faults phenomenon in DC photovoltaic (PV) systems. The paper gives an overview of arc detection methods proposed in literature and presents a preliminary experimental characterization of the arcing current, focusing the attention on series arcs, whose detection is particularly challenging. Experimental tests are carried out, both in laboratory and on field, in order to investigate some relevant characteristics in the arcing current, which can be feasible for the arc detection purpose. Both arcing and non-arcing current signals are acquired and compared in both time and frequency domain. On-field measurements are carried out on a real photovoltaic system, in a…