0000000000054067
AUTHOR
Cosentino V.
Metrological performances of voltage and current instrument transformers in harmonics measurements
In the new electrical system scenario, the increasing presence of non-linear loads and renewable energy sources makes the measurement of harmonics an essential task. The accuracy of harmonic measurement firstly depends on the used instrument transformers for voltage and current sensing. Since the behavior of instrument transformers in non-sinusoidal conditions is not always well defined, this paper presents an experimental study on the metrological performances of current and voltage instrument transformers (CTs and VTs) in the presence of harmonics. Proper tests procedures are defined and measurement setups are developed for both CTs and VTs calibration. The analysis is carried out by usin…
Measurement issues on harmonic analysis according to the IEC 61000-4-7
The objective of this article is an analysis of measurement issues related to the implementation of digital signal processing techniques for harmonic analysis, by means of FFT algorithm with different interpolation algorithms (linear, quadratic and cubic) and different sampling rates. A comparative analysis is made on errors on harmonics measurement obtained in the various case study analyses. Such errors are compared with the IEC 61000-4-7 limits. The study is supported by both simulation and experimental tests; these last are performed with different acquisition boards for signals acquisition.
A single-point approach based on nonactive power factor for the assessment of harmonic distortion sources in power systems
This paper presents a study on the use of power factor indicators for the assessment of harmonic distortion sources in power systems. In detail the analysis is focused on the comparison between the proposed nonactive power factor (Q1/N) and the indicators of the IEEE Std. 1459-2010, and on the indicators feasibility in identifying the presence of harmonic distortion sources. As discussed in the paper, the proposed indicator can be evaluated with good accuracy, by means of typical power quantities measurements at the point of common coupling (PCC). Thus its measurement can be feasibly implemented in commercial platforms used for smart metering applications. To verify the proposal validity, s…
Impact of non-programmable distributed generation in an islanded microgrid: the case study of Ustica
The paper presents a systematic analysis of nonprogrammable distributed generation impact in an islanded microgrid Different issues have been analyzed, with a special focus on the most significant ones in a small islanded network. To this aim, the case study of Ustica island was considered A digital twin of the MV network was developed starting from the network topology data and the power measurement acquired in each secondary substation. Simulations were then performed in the hypothesis of a large increment of distributed generation installation into the network. A discussion is then reported on which are the main technical issues to be faced in the considered case study.
Time domain symmetry parameters analysis for series arc fault detection
This paper presents a feasibility study of exploiting the symmetry of some parameters for series arc fault detection in electrical circuits. The considered parameters are defined in the time domain and they are based on the current signal derivative and the evaluation of cross-correlation between subsequent observation windows. The analysis is carried out for AC systems, starting from an experimental characterization, which has been carried out in accordance with the Standard UL 1699 requirements for "unwanted tripping tests"and "operation inhibition tests"of arc fault circuit interrupters (AFCIs). The results obtained in different load conditions show that the proposed parameters can be us…