Impact of a power ramp event on photovoltaic system power quality under different weather conditions and operating powers

This paper presents a comprehensive experimental analysis of voltage quality, focusing on the impact of passing clouds on the performance of a 9.5-kWp photovoltaic grid-connected system. This system is composed of three 3.2-kWp subsystems installed on the flat roof of the Renewable Energy Development Institute (CDER) in Algeria. In this paper, we analyzed and evaluated short-term and long-term voltage flicker indexes (Pst and Plt), power ramp events on power quality, harmonics caused by the inverter and by the loads connected to the PCC, and very short voltage variation (VSV). The power quality parameters at the inverter output side have been measured using the CA 8335 power quality analyzer. The results show that the change in density of the passing clouds has a linear relationship with the change in intensity of the ramp event and the power generated by the photovoltaic system (PVS). Moreover, in the case of a bidirectional electrical network and with the presence of nonlinear loads, the recorded flicker has exceeded the legal limits due to the second-order harmonic effects generated by nonlinear loads and the level impedances at the grid and the PV system connection point. The concluded results obtained can be an additional benefit for the electricity distribution networks in Algeria, in light of the proliferation of photovoltaic systems.