1,721,007 research outputs found
Time-varying harmonic currents from large penetration electronic equipment
No full textThe chapter deals with the characterization of time varying harmonic currents from large penetration electronic equipment.
The time-varying characterization of single-phase NL appliances of large penetration into end-use such as desktop PC, printer, photocopier and cell phone battery charger has been presented first. The time-varying behavior of harmonics has been investigated through the use of specific measurement equipment allowing continuous harmonic monitoring. Pdf’s and distribution functions have been calculated for the large amount of data made available from the monitoring activity.
Then, an experimental procedure has been presented which helps predict the mutual influence between several single-phase electronic equipment and the LV distribution network.
Two parametrical models can be identified from monitoring results. The models are expressed via some curves that have been defined: 1) attenuation curves; 2) impact curves. The attenuation curves allow to parametrically estimate the effects of cancellation phenomena on net harmonic currents. The impact curves allow to parametrically predict the NL load influence on voltage harmonic distortion at PCC
IEC Std. 61000-3-2 harmonic current emission limits in practical systems: need of considering loading level and attenuation effects
No full textCharacterization of Fluctuating Harmonics from Single-Phase Power Electronics Based Equipment
No full textselezionato per pubblicazione su Rivista internazionale COMPE
Characterization of fluctuating harmonics from single-phase power electronics-based equipment
No full textThe present paper is intended to analyze time-varying harmonic absorption of single-phase non-linear loads. To this aim, it is demonstrated that a continuous harmonic monitoring can be of a certain utility, since this practice allows a better characterization of harmonic spectra and an improved understanding of impact due to the various stages of typical operation. Some selected results obtained from a wide monitoring activity performed in a lab are reported in this paper. The results are relevant to NL appliances with power ratings ranging from less than 10?W to several hundred watts, such as desktop PC, printer (both laser and ink-jet), cell phone battery charger, and photocopier. The data thus obtained have been processed in order to determine probability density functions and distribution functions well evidencing the time-varying behavior of harmonic content of the absorbed current. Since a continuous harmonic monitoring allows to follow the nearly instantaneous evolution of the physical quantities (voltage and current) a cross-correlation based analysis of the various harmonic quantities among themselves is more meaningful than the monitoring activities providing longer observation time windows (up to minutes). The results obtained with such calculations can provide good indications for determining the origin of the time-varying behavior as evidenced
Short-Term Forecasting of Municipal Load Through a Kalman Filtering Based Approach
No full textThe paper illustrates some results of a research activity in the field of electric short-term load forecasting (STLF) applied to load areas of municipal or regional extension. To this aim a forecasting procedure has been implemented that is based on time series (univariate) model using a Kalman filtering approach. The model has been applied to data available for a municipal electric utility in Italy. The results thus obtained are reported in the paper and discussed. Some guidelines are finally deduced for farther research work still required in this specific field of forecasting problems
Experimental assessment of energy saving due to trains regenerative braking in an electrified subway line
No full text- …
