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

Abstract

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 Daner 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.

Evaluating harmonic voltage distortion in load‐variating unbalanced networks using Monte Carlo simulations

“…When compared to previous works, this method provides some interesting advantages. For instance, the load aggregation technique proposed in [19] can only be applied after obtaining the diversity factors, which can be made based on measurements or in simulations. It should be noticed that diversity factors for combined single-phase and three-phase loads connected simultaneously to the grid are not well established, which limits the application of the method in [19].…”

“…Depending on the phase angle of the individual harmonic currents, attenuation is expected to occur [17,18]. In this regard, diversity factors, which are used to estimate the net harmonic currents of the sum of homogenous single-phase power electronic loads, have been established in [19]. However, diversity factors related to other types of nonlinear single-phase and three-phase loads are not well established, which makes it hard to obtain them for a large number of non-linear loads [16].…”

Analytical and experimental discussion of a circuit-based model for compact fluorescent lamps in a 60Hz power grid

“…The impact of these problems can be assessed if the attenuation and diversity phenomena are correctly estimated by accurate models. Attenuation is defined in and (Mansoor, Grady, Chowdhury, & Samotyi, 1995) as the interaction between the distorted voltage and current, mainly due to the common system impedance. As a result of this interaction, when the source voltage is distorted, a reduction in current harmonics produced by other loads can take place (Salles, Jiang, Xu, Freitas, & Mazin, Oct. 2012).…”

“…This cancellation is due to the dispersion in the phase angles of the currents, which is related to the structural characteristics of the load and variations in either the demand or parameters such as the rated power and power factor (Mansoor, Grady, Chowdhury, & Samotyi, 1995) (Task Force on Harmonics Modeling and Simulation, 1996).…”

Economic impacts of power electronics on electricity distribution systems

“…These are based on a concentric copper service drop cable of 1 Â (4.00 þ 4.00) mm 2 , and an internal copper wire of 1 Â (2.5 þ 2.5) mm 2 , besides a segment of 20 m for both the service drop and internal wiring. The additional losses in these conductors were based on developed methodology in [16] and consider the harmonic reduction given in [15]. These losses (I 2 R) were estimated by the difference in current circulation with one half the THD i generated by each TV sets, approximately 120% [10,14], compared with zero THD i .…”