Harmonic voltage distortion generated by grid-connected photovoltaic generators

This paper addresses a number of specific aspects concerning the waveform distortion occurring in grid-connected photovoltaic (PV) plants. The focus is set on the characterization of the waveform distortion under different operating conditions in field measurements and laboratory tests, on the relationships among the measured quantities and the requirements of the power quality standards, and on the harmonic and interharmonic modelling of multiple grid-connected PV inverters. The results of the waveform distortion analysis for harmonic currents and voltages show that in some practical cases the current distortion can be significantly higher than in normal test conditions. From harmonic analysis on multiple PV inverters, the results show that low-order harmonics sum up almost arithmetically, whereas the higher-order harmonics and the interharmonics sum up in an almost Euclidean way.