Niclas Björsell, Peter Händel
BENEFITS WITH TRUNCATED GAUSSIAN NOISE IN ADC HISTOGRAM TESTS

One method to characterize ADCs is to use a histogram, where Gaussian noise may be used as stimulus signal. However, a Gaussian noise signal that excites all transition levels also generates input values outside working range of the ADC. Modern signal generators can generate arbitrary signals. Hence, excluding undesired values outside the ADC full scale can minimize test sequences. Truncating the signal to the working range gives further advantages, which are explored in this paper. The statistical properties is theoretically evaluated and compared. It is shown that accuracy increases for a fixed sample length and that variation over transition levels decrease.

Daniele Gallo, Carmine Landi, Nicola Pasquino, Nello Polese
AN ADVANCED LABORATORY ARCHITECTURE FOR METROLOGICAL CONFIRMATION OF MEASUREMENT DEVICE FOR POWER QUALITY EVALUATION

Continuous monitoring of power grid aimed at assuring compliance of power quality indexes to standard requirements, calls for a wide range of instruments, each devoted to a different measurement. Metrological confirmation of the whole set of devices and instruments turns out to be a complex task – because of the variety of characteristics to be tested – that requires time to be com-pleted which eventually determines high costs, not to mention that during confirmation activities in-struments cannot be used. The purpose of the laboratory presented is to provide a complete set of con-firmation services through local branches distributed over the territory. A central laboratory plans and supervises activities which are then delegated to peripheral labs employing travelling standards to perform confirmation directly at client’s side thus reducing sensibly times of off-line operations. Experimental results from two different kind of measurements that require fast acquisition in one case and accurate acquisition in the other are reported as an example of the wide range of possible applications.

G. Andria, L. Filotico, A.M.L. Lanzolla, F. Piccininni, T. Scialpi
MONITORING OF SYSTEM PERFORMANCES OF A FULL THERMAL ENERGY PLANT – UNCERTAINTY EVALUATIONS

This work proposes the development and characterization of innovative domestic heating system driven by solar assisted heat pump in order to increase the system efficiency. A suitable on-line measurement system of overall observable quantities has been integrated in the plant, to give accurate and updated measurements of all the variables interesting the whole system. A more detailed analysis of quantities that main influence the system performances has been carried out, developing a suitable mathematic model able to describe and control the behaviour of interested phenomena. Finally some information about reliability degree of model has been provided. The use of advanced control and monitoring of several interested quantities has allowed optimising the global system efficiency.

Stanislaw Galla, Beata Palczynska, Ludwik Spiralski
RANDOM COMPONENTS INFLUENCE ON THE VALUES CHARACTERISING PERIODIC DISTURBANCES IN LOW VOLTAGE SUPPLY LINES

The paper analyses the random components influence on the values characterising periodic disturbances in the supply line voltage on the example of the total harmonic distortion coefficient (THD). It presents the method to determine the uncertainty in the THD coefficient measurement, which takes into account the correlations appearing between the fundamental component and the successive harmonics of the supplying voltage, and also between particular harmonics. The analysis of the results from the total harmonic distortion coefficient measurements in the supplying voltage of a motor drive system with the electronic power converter is presented.

Claudio De Capua, Annalisa Liccardo, Emilia Romeo
NEW SYNTHETIC POWER QUALITY INDEXES AND ASSOCIATED MEASUREMENT PROCEDURES

In recent years, particular attention has been focused about problems regarding Power Quality. In 1995, IEEE technical committee defines some fundamental indexes capable of quantifying the quality of the power generation and transmission. In authors’ opinion, the list of the proposed indexes seems to be inadequate to exhaustively detect voltage or current disturbances at all. In this paper, the authors propose for new indexes and a respective original procedure for measuring and evaluating voltage sags, according to the standards definitions.