Harmonic characterization of grid connected PV systems & validation with field measurements

Rooftop Solar Photovoltaic (PV) systems installations have been increasing in the Low voltage distribution networks due to decreased cost and government incentives (e.g. feed-in-tariff). The high penetration of these PV systems can inject harmonics into the network causing problems to sensitive loads and controllers of loads. Due to the solar irradiation dependency, the power generation is variable. Hence, the harmonic emissions from each inverter and their aggregation may be altered. In this paper, a detailed assessment of PV inverters harmonics for different operating conditions has been performed. Regarding this, the assessment has been supplemented with simulations in two case studies. Moreover, the investigation has been conducted with field tests at the University of Queensland PV site. Field measurement data for various operating days at the inverter level were recorded using Power Quality analyzers. The collected data has been analyzed, and further validated with the simulation results. Results show that the harmonic behaviors of both voltage and current waveforms are comparable with simulations trends.