Assessment of Harmonic Distortion in small grid-connected photovoltaic systems

This paper aims to analyze the interaction between three different solar inverters, coupled to a small grid-connected photovoltaic system (located at north of Brazil). Total Harmonic Distortions of voltage (THDv) and current (THDi) are analyzed, and thus, the power quality delivered by each of these equipment to local distribution grid is evaluated. It is found, through operational data collected, that the analyzed small solar inverters results in considerable THDi's levels when subjected to power levels below its rated value but, the resulting THDv's, in all analyzed inverters, are within the acceptable range according to technical standards. Finally, another important point analyzed is the installation power factor that can change significantly depending on the PV system production capacity and the installation demand profile.