A novel procedure based on lab tests for predicting single-phase power electronics-based loads harmonic impact on distribution networks

The paper illustrates the results of an experimentally based procedure aimed at estimating the mutual influence between single-phase nonlinear (NL) loads and the upstream supply system. The procedure provides harmonic monitoring of a nonlinear appliance supplied from a low-voltage (LV) distribution network outlet. The appliance is connected to the outlet through a variable impedance whose components can be adequately varied in order to artificially reproduce upstream system and load variations. The monitoring results allowed “ONE”? to define both current and voltage harmonic spectrum variations versus some parameters that have been found as most influencing the attenuation effects. From the monitoring activity performed on personal computers, some curves have been determined that can be used for a parametrical estimation of: a) the attenuation effect of voltage distortion on net harmonic current drawn by the NL appliance; and b) the impact of the NL appliance on voltage distortion at the point of common coupling in terms of voltage total harmonic distortion (VTHD) increase.