An investigation of harmonics attenuation and diversity among distributed single-phase power electronic loads

Widely distributed single-phase power electronic loads are an increasingly important source of harmonics in power distribution systems. The objective of this paper is to investigate the cumulative harmonic current characteristics of a large number of such loads. A complete analytical model for the most common load type is derived. This model is then used to investigate the impact of 1) interaction due to a shared source impedance, 2) variation in power level, and 3) variations in circuit parameters, on individual and cumulative current harmonics. The key findings of the paper are that * diversity and attenuation are very important factors in predicting the behavior of distributed single-phase power electronic loads, especially for the higher-order harmonics, and that ** due to these two factors, the commonly-used fixed current injection method, using arithmetic sums of harmonic current magnitudes, can significantly overestimate the cumulative harmonic currents produced by these loads.