Nicola Pasquino

A New Methodological Approach to Quality Assurance of Energy Meters Under Non-Sinusoidal Conditions

In this paper the authors propose a methodology to guide verification of energy meters under sinusoidal and non sinusoidal conditions. At first, it is presented a brief review about definitions of the quantities that should be measured or monitored for revenue purposes and their relationship with electrical quantities that are recognized to be important in terms of metering accuracy. Then, a design of experiment that allows testing meters under a combination of disturbances showing positive and negative correlation is described. Finally, a hardware and software system to perform verification procedures in complex situation is presented with some preliminary analyses

Design and Calibration of an Objective Flickermeter

Measurement of light flicker according to current standard EN ISO 61000-4-15 is performed through measurement of voltage variations filtered by a model of a 60 W/230 V incandescent lamp. Hence, differences in current illumination systems technology can determine discrepancies between light flicker measurements performed under the same voltage flicker. In the paper, a method to measure light flicker with a low cost digital device, based on light intensity measurements, is proposed, thus including the lamp itself in the measurement process. In this way an objective measurement of light flicker is obtained. The metrological characterization of the device has been implemented by means of an automatic testing station which includes a standard IEC flickermeter (Norma D6000) as reference instrument. Thanks to its portability, the instrument can be used to measure light flicker no matter the illumination system used, over a wide range of environments spanning from home/office to industrial locations, and including the environmental condition (i.e., ambient light and reflection by walls and objects) in the measurement process

ANOVA-Based Approach for DAC Diagnostics

In order to assess the performance of digital-to-analog converters (DAC) the attention is generally focused on the integral nonlinearity INL. Useful diagnostic tools to detect the causes of poor linearity are the linearity and intermodulation errors, which can be evaluated from INL measurements. Linearity and intermodulation errors highlight and quantify erroneous calibration and unwanted interactions between current sources inside the DAC hardware. Unfortunately, their estimates, particularly those related to high-order intermodulation errors are characterized by high uncertainty. On the base of their very uncertain value, it is difficult to establish if interactions represent relevant factors or not. It is shown that by means of the analysis of variance (ANOVA) the relevance of intermodulation errors can be assessed from a limited set counting a minimum of two INL measurements. ANOVA is in fact capable of distinguishing if the variance in INL measurements has to be addressed to active factors or noise, even if the effect of each factor is widespread upon different elements of the INL array and in different combinations with the other factors.

Multisensor Network for Urban Electromagnetic Field Monitoring

A distributed system of sensors for surveying the electromagnetic (EM) field exposure is presented, and its main design characteristics and performance are discussed. The system overcomes the coverage restrictions of commercial measurement systems by adopting fully mobile sensors that communicate with a central unit through the cellular network, so that the widest area can be monitored with the smallest possible number of probes by mounting them onto transportation means. The system also benefits from the low cost per unit area served and for maintenance, which make it of great interest both for administrations that need to deploy field measurement activities and for researchers involved in statistical characterization of an EM urban environment. Communication between sensors has been planned according to such specifications that could allow integration of sensors built by different manufacturers, and it largely relies on the use of open transmission control protocol/internet protocol (TCP/IP). The sensor network has been used in a broadband measurement campaign over a typical urban environment, and results obtained are shown together with specific statistical analysis of both sampled and root-mean-square values.

Exposure to 50 Hz electromagnetic field raises the levels of the anti-apoptotic protein BAG3 in melanoma cells†

The expression of the anti‐apoptotic protein BAG3 is induced in several cell types by exposure to high temperature, oxidants, and other stressful agents. We investigated whether exposure to 50 Hz electromagnetic fields raised BAG3 levels in the human melanoma cell line M14, in vitro and in orthotopic xenografts. Exposure of cultured cells or xenografts for 6 h or 4 weeks, respectively, produced a significant (P < 0.01) increase in BAG3 protein amounts. Interestingly, at the same times, we could not detect any significant variation in the levels of HSP70/72 protein or cell apoptosis. These results confirm the stressful effect of exposure to ELF in human cells, by identifying BAG3 protein as a marker of ELF‐induced stress. Furthermore, they suggest that BAG3 induction by ELF may contribute to melanoma cell survival and/or resistance to therapy. J. Cell. Physiol. 226: 2901–2907, 2011.

A Remotely Controlled Onboard Measurement System for Optimization of Energy Consumption of Electrical Trains

Reduction in energy consumption in electrical railway traction systems has become a vital need. The effort spent in providing better quality services implies increasing speed and, therefore, an increase in energy consumption. Various techniques are usually adopted to improve train performances. They span from modifying the vehicle structure to improving the motor. In this paper, a different way to reduce power absorption is presented, which is based on an appropriate interpretation of the traction diagram, along with the absorption curves. Measurement data are available by means of an onboard monitoring system that measures all the electromechanical quantities of the train course and sends them through a network connection to a remote control station. The evaluation of measurement uncertainty, the procedure to obtain the optimized protocol for train operation, and the experimental data obtained when the optimized protocol is applied are also presented.

An efficient extension of the zero-crossing technique to measure frequency of noisy signals

The paper contains a proposal for the estimation of the frequency of a sine signal corrupted by zero-mean additive white gaussian noise. The method resorts to the histogram of the time intervals between adjacent zero-crossing samples. Validation has been carried out for various noise levels and results show that the relative error is much less than other algorithms for frequency estimation. Performances are also compared to those of numeric counters. The method can be easily implemented of low cost devices and is computationally very efficient.

Uncertainty and reproducibility in measuring the data acquisition system immunity to conducted disturbances

The paper presents an original methodology for testing the data acquisition system immunity to conducted disturbances and for evaluating the typical uncertainty intervals to be assigned to these kinds of measurements. As in any data measurement system, even in those consisting of a desktop computer equipped with a PCI data acquisition board, several devices and components are involved in the process of acquiring, sampling and digitizing the analogue signal, and eventually presenting the digital values to the user. Therefore, there are many possible coupling paths between the measurement system and external electromagnetic disturbances, in principle both radiated and conducted, which would require a large number of configurations to be tested. Indeed, with particular reference to radiated couplings, their effects generally depend on the adopted test setup. In addition, the electromagnetic boundary conditions of the test site can significantly affect the measurement results. Both these aspects should be carefully taken into account because they are the main cause for ambiguous results and well-known issues in inter-laboratory comparisons. In this framework, the aims of this study are (i) to investigate which components or component configurations influence the data acquisition system immunity most significantly; (ii) to provide a practical way to effectively test these types of measurement system and (iii) to assess the related uncertainty budget in order to qualify the test results. Finally, the site-to-site reproducibility of the measurements has been evaluated by comparing results obtained in two different laboratories.

A ground monitoring system based on TDR tests

A ground monitoring system that exploits electromagnetic field properties of accounting of both physical and geometrical features of the surrounding medium is proposed. The system is based on TDR tests, assisted by a control and processing unit, and aims at detecting starting cavities underground in the soil. The digital signal processing approach deployed for waveform analysis, which plays a fundamental role in detecting and characterizing underground anomalies, is described.

Characterization of the radio propagation channel aboard trains for optimal coverage at 2.45GHz

The paper investigates the intra-car propagation properties of the radio channel at 2.45 GHz aboard trains. Results show that path loss is slightly smaller than that in free space and that it does not change significantly with the propagation direction. The delay spread strongly depends on polarization. Finally, the model that best fits the dependence of the coherence bandwidth on delay spread is obtained. The final aim of the presented study is to use such model to evaluate the maximum distance between access points mounted aboard that results in a delay spread that still allows transmission of the bandwidth required for optimal performance of the wifi service.