Impact of Single-Phase PV Systems on the Harmonic Distortions of Costa Rican LV Grids

The increasing penetration of photovoltaic (PV) generation in low voltage (LV) distribution networks may not only impact the power quality of the grid in terms of overvoltages, but it also can bring about interactions with the harmonic distortions in the grid. However, large-scale harmonic impact studies pose technical difficulties when working with inverter-based resources (IBR) such as the complex models required for simulation, computational burden, and the uncertainty of vendor-specific control parameters and topology. This paper presents a sensitivity analysis of a real LV distribution circuit model in Costa Rica, changing the topology and parameters of single-phase (1ph) PV generators to show their impact on the harmonic distortion levels. This study was commissioned by Costa Rican distribution utilities to evaluate if PVs are to blame for the harmonic pollution of modern LV grids. Overall, the results show that the PVs lower the grid distortion levels. It was also determined that the measurement filter cutoff frequency, the front-end filter size, and the feedforward topology are the most relevant parameters in these studies.