José Carlos Oliveira, Diamantino Silva Freitas, Artur Capelo Cardoso
ELECTRONIC CIRCUITS PARAMETRIC MEASUREMENT: A NEW APPROACH IN ELECTRICAL METROLOGY

The measurement of electrical quantities in electronic circuits is inscribed in the non-parametric world for a long time. Multimeters, Oscilloscope and Network Analysers are the preferred tools used by engineers. Parametric identification allows a new step in circuit characterization. This approach opens new perspectives in the process of electronic circuit’s design. The present paper presents a solution to the problem of parametric characterization. To allow the simulation and validation of the results a new simulation tool is also presented. The proposed simulation solution uses modified off-the-shelf standard software packages, integrates them closely, offering an expeditious way of bringing mathematical postprocessing power to a standard electronic simulation package, in the framework of circuit design and characterization or measurement.

Petar Knezevic, Vedran Srsen, Kresimir Segaric
ANALYSIS OF SOME QUALITY OF SERVICE PARAMETERS' IMPACT ON END-TO-END DELAY MEASUREMENTS IN VOIP NETWORK

Internet users and Internet service providers are using all kinds of tools for monitoring the communication network. Most of the measurements are done by inserting simulated traffic into the network and observing network performances. When used to measure some time-sensitive applications, like Voice over IP (VoIP), these tools in coherence with some network configuration techniques can result with inaccurate measurement result. We discuss some of those configuration techniques and their influence on delay measurements, and introduce possible solutions.

Mladen Boršic, Damir Ilic, Nadža Milanovic, Luka Ferkovic, Pasquale Daponte, Aniello Cimitile, Sergio Rapuano, Mihail Marinov, Andrea Aiello, Gianpaolo Mercurio, Gioachino Truglia, Višnja Gašljevic, Roman Vulpe
ESTIMATION OF THE UNCERTAINTY IN MEASUREMENT OF THE ELECTRIC ENERGY - ITALIAN-CROATIAN PROJECT

The Faculty of Electrical Engineering and Computing Science, University of Zagreb and the Faculty of Engineering University of Sannio signed, in the year 2001, the Agreement of Cooperation International Co-operation for the Research Doctorate in Information Technology with the aim at collaborating for the activation and the development of joint doctoral degree courses.
The President of the Province of Benevento and the President of the City Assembly of Zagreb signed, the same year, the Letter of intent for cooperation. As the first step in this cooperation will be the realisation of the Italo-Croate project Estimation of the Uncertainty in Measurement of the Electric Energy funded by the Italian Ministry of Education, University and Research (Ministero dell'Istruzione, dell'Universita e della Ricerca) and Croatian Ministry of Science and Technology (Ministarstvo znanosti i tehnologije).
The eolic electric energy, as a pure energy, becomes increasingly important in Italy. The high voltage to medium voltage transformer sub-stations in Montefalcone, having installed energy of about 180 MVA, will be the test stations to evaluate the uncertainty in measurement of electric energy generated by eolic generators. The result should be the fair and transparent energy rating.
The group of researchers from Faculty of Electrical Engineering and Computing, University of Zagreb, Croatian Metrology Society, Zagreb, and Universita degli Studi del Sannio, Benevento will try to find all the sources of possible errors in measurements. At the end, two or three researchers will carry out internationally recognised doctorate dissertations.

Jerzy Nabielec, Barbara Bisztyga
DYNAMIC ERROR CORRECTION FOR MEASUREMENT SYSTEM WITH DIFFERENTIATING SENSORS

The dynamic measurement is considered. The measurement system with differentiating sensor is taken into account. The 'blind' method has been applied to solve the dynamic error correction. Discrete time corrector has been adapted. Simulation technique has been used to verify the usefulness of the correction.

R. Micheletti, R. Pieri
WALSH DIGITAL FILTERING ALGORITHM FOR HIGH SPEED DISTANCE PROTECTION WITH IMPROVED BEHAVIOR

Distance relays must estimate accurately and quickly the distance to the fault even in presence of highly distorted input signals. Several digital filtering algorithms for distance relays have been proposed and some of them are used in practical applications. However nonlinear loads are becoming more and more common in electric power systems and that increases the corruption level of signals. For this reason, the study of digital filtering techniques for the extraction of fundamental components from highly corrupt voltage and current waveforms is of vital importance for the development of algorithms applied to the digital protection of transmission lines. The studied technique proposed in this paper is based on Walsh functions.