Appendix A: Time‐Varying Harmonic Currents from Large Penetration Electronic Equipment

Abstract

The international literature of this sector has not yet covered time-varying harmonic absorption of electronic equipment in detail, even though the ever increasing penetration of such equipment makes the prediction of harmonic impact an urgent problem.In order to investigate time-varying behavior of harmonic spectra adequately specific harmonic monitoring systems are required which allow a continuous recording of harmonic quantities [1][2][3][4]. Specific and quite expensive commercial products or custom-made equipment are required.The continuous monitoring can be of a certain utility but also for low-demand single-phase nonlinear loads, since this practice allows a better characterization of harmonic spectra and an improved understanding of the impact due to the various stages of typical operation as well. To this end, some selected results which were obtained from a wide monitoring activity performed in the laboratory over the last few years are reported [5][6][7][8][9].The measurement activity can be performed by using customized monitoring equipment with the simplified scheme illustrated in Figure A1.The equipment permits the simultaneous and synchronous sampling of multiple singlephase voltage and current signals by using two different acquisition boards dedicated to voltage and current channels, respectively. Details of the equipment characteristics are reported in [5][6][7][8][9].This appendix deals with the characterization of time-varying harmonic currents from large penetration electronic equipment. The time-varying characterization of single-phase Time-Varying Waveform Distortions in Power SystemsEdited by Paulo F. Ribeiro