Lorenzo Peretto

The role of measurements in the smart grid era

This paper is devoted to the smart grid era which requires not only knowledge in the field of electric energy but also of many other fields like information technology, communication, control and automation, education, and nanotechnology. This universal effort will be effective if and only if the management and control of energy includes reliable information from accurate measurement methods and voltage and current sensors.

A simple lamp-eye-brain model for flicker observations

This paper suggests a simple eye-brain model for light flicker studies and examines the response of such a model to voltage flicker. Calculated flicker curves representing the objectionable threshold of voltage fluctuation were found to match reasonably well the experimental IEEE curves. The model may be used to predict flicker curves for diverse voltage flicker waveforms and for lamps with different time constants and gain factors.

Investigation on Multipoint Measurement Techniques for PQ Monitoring

The problem of locating the sources of harmonic distortion in power networks is still a critical task. Several methods based on multipoint measurement techniques have been recently proposed in the literature for harmonic-pollution monitoring. The main goal of this paper is to compare the two most powerful tools designed for this purpose. In this paper, the results of both computer simulations on an IEEE test network and experimental tests performed by means of simultaneous measurements on an ad hoc benchmark power system are presented along with a discussion on the practical usability of such monitoring techniques

Theoretical Analysis of the Physiologic Mechanism of Luminous Variation in Eye-Brain System

Flickermeters provide correct measurements only when the source of flicker is an incandescent filament lamp. Due to the rapid proliferation of modern lamps there is the need to make available flickermeters that will quantify the degree of annoyance caused by any kind of lamp. It is widely accepted by scientific community that the preferable way to reach this goal is to directly measure the emitted light instead of the voltage supplying the lamp itself (as implemented by the actual flickermeters). This paper presents the results of a study aimed at modeling the eye-brain chain in order to predict the response, and hence the sensation, of a human being to a given luminous stimulus. The model has been experimentally tested with the standard input signals recommended for testing existing flickermeters. Preliminary test results are encouraging. The authors believe that the presented theoretical model may serve as a kernel for defining a general mathematical model for predicting the response of the eye-brain system to generic luminous fluxes of known spectrum and modulation

A numerical approach to the evaluation of uncertainty in nonconventional measurements on power systems

The application of the rules endorsed by the ISO Guide to the expression of uncertainty in measurement (GUM) can turn into a difficult task when quantities that characterize the operation of modern power systems are measured by means of DSP-based instruments. A numerical approach to easily tackle this task is proposed in this paper, as an alternative to the uncertainty evaluation based on the analytical solution of the uncertainty propagation law, as prescribed by the GUM. The validity of the numerical approach, which is based on a Monte-Carlo procedure, is first proved in the case of the spectral analysis of a periodic signal, which is the first step for many nonconventional measurements. Then the evaluation of the accuracy of a method for the measurement of the harmonic losses in a power transformer supplying nonsinusoidal load currents is dealt with as an application example.

Remote Didactic Laboratory “G. Savastano,” The Italian Experience for E-Learning at the Technical Universities in the Field of Electrical and Electronic Measurements: Overview on Didactic Experiments

The Remote Didactic Laboratory Laboratorio Didattico Remoto - LA.DI.RE. ldquoG. Savastanordquo is the e-learning measurement laboratory supported by the Italian Ministry of Education and University. It involves about 20 Italian universities and provides students of electric and electronic measurement courses with access to remote measurement laboratories delivering different didactic activities related to measurement experiments. In order to demonstrate the versatility for didactic use, the overview of some experiments is given. The didactic experiments summarized in this paper concern measurement characterization of instruments and communication systems, measurement devices for remote laboratories, basic electrical measurements, magnetic measurements, electromagnetic-interference measurements, and signal processing for measurement applications.

Low-cost DSP-based equipment for the real-time detection of transients in power systems

A novel solution for the real-time detection of transients in power systems is presented. It relies on a simple and robust algorithm, which analyzes the signal in the time domain, does not involve high computational burdens, does not require a high amount of memory, and has been implemented on a low-cost DSP. Experimental results showing the very good system performance are provided.

A Measurement System for the Analysis of the Response of the Human Eye to the Light Flicker

The response of the human eye to flicker depends on the type of lamp used. Standard flickermeters measure the voltage across the lamp and assumes a 60-W incandescent lamp as a light source. When a different lamp is the light flicker source, standard flickermeters give erroneous results. This paper presents a dynamic model of the eye-brain response to flicker. The model is based on the analysis of the light emitted by the lamp. A suitable measurement system has been developed, and three different kinds of lamps have been considered. Experimental results show how the emitted light spectra and the human eye response to different colors combined to determine the level of annoyance. The uncertainty affecting such results, which arises from the hardware of the developed system, has been also estimated.

Remote Didactic Laboratory “G. Savastano,” The Italian Experience for E-Learning at the Technical Universities in the Field of Electrical and Electronic Measurement: Architecture and Optimization of the Communication Performance Based on Thin Client Technology

The Remote Didactic Laboratory Laboratorio Didattico Remoto -LA.DI.RE. “G. Savastano” is an e-learning measurement laboratory supported by the Italian Ministry of Education and University. It provides the students of electric and electronic measurement courses with access to remote measurement laboratories, delivering different didactic activities related to measurement experiments. The core of the software architecture is the integration of the Learning Management System (LMS) with the remotely accessible measurement laboratories through web services and thin client paradigm, providing a new approach to remote experiments on measurement instrumentation. The overview of this paper is on the different solutions concerning the thin client technology, and the solution implemented is described. This solution takes into account the delivered services to students and teachers and permits optimization of the communication performances. The results of the comparison among the performances of different implementations of the thin client paradigm highlight the advantages of the adopted solution. As a consequence, the description of the thin client protocol implemented, together with the presentation of the LMS and delivered services given in a previous paper, makes an exhaustive analysis of the software architecture of the LA.DI.RE. “G. Savastano.”

Implementation of multi-point measurement techniques for PQ monitoring

The problem of locating the sources of the harmonic distortion in power networks is still a critical task. Several methods based on multi-point measurement techniques have been recently proposed in the literature for harmonic pollution monitoring. The main goal of this study is to compare the two most powerful tools designed for this purpose. In this paper the results of both computer simulations on an IEEE test network and simultaneous measurements on ad-hoc experimental benchmark power system are presented along with a discussion on the practical usability of such monitoring techniques.