The generation and analysis of non-standard frequency components and even harmonics in AC distribution systems

In this dissertation, the generation and analysis of non-standard frequency components and even harmonics in distribution systems is studied in detail. The generation of non-standard frequency components is attributed to the extensive use of power electronic devices. Those devices include integral cycle controllers (ICCs), Kramer drives, cycloconverters, and wind turbines. Power system even harmonics can be generated from half-wave rectifiers, three-phase half-controlled bridge rectifiers, arc furnaces, and saturated direct current (DC) biased transformers.; Firstly, several power quality indices are redefined for the consideration of non-standard frequency components. An innovative concept, group frequency, is proposed to facilitate the analysis of non-standard frequency components. Group frequencies are applied for the analysis of non-standard frequency components of ICCs, Kramer drives, and cycloconverters.; Secondly, non-standard frequency components and even harmonics can cause the asymmetry of voltage or current waveforms. Asymmetry in this sense refers to the case where the positive and negative peaks are of different amplitude. The waveform asymmetries have impact on the loads sensitive to voltage or current peaks. A novel power quality index, asymmetry factor, is proposed to evaluate the difference between voltage (or current) positive peaks and negative peaks.; Thirdly, the non-standard frequency components of ICCs are studied. ICCs are switched controllers that interrupt load currents. ICCs are switched at an integral number of cycles to affect this control. A switching strategy in selecting optimal control patterns based on minimizing the value of voltage flicker is proposed. The impacts of single-phase phase ICCs with resistance inductance (RL) loads are also studied. An alternate switching strategy is proposed to eliminate the undesired DC components in load currents for RL loads.; Lastly, the non-standard frequency components of cycloconverters are studied. A cycloconverter is a power electronic device used to convert constant voltage constant frequency alternating current (AC) power to adjustable voltage adjustable frequency AC power without a DC link. The impact of cycloconverters on power quality is studied, and the relationships between power quality indices and control strategies are developed. Control strategies are proposed to minimize the power quality impact of the cycloconverter.