Impact of resources distribution on high-frequency behaviour of photovoltaic systems

In this study, the distribution effect of grid-connected inverters in photovoltaic (PV) plants is analysed. In fact, the interaction dynamics between different arrangements of distributed PV inverters and the grid are thoroughly compared. To this aim, the total power of all arrangements of distributed inverters is considered constant, which is called fixed-power arrangements in this work. Accordingly, this study first develops the model of grid-connected current-controlled inverters (CCIs). Then, by applying the impedance-based criterion, the effect of CCIs distribution on their stability is evaluated. Despite the fact that each CCI model is obtained based on the same stability margins, different distributed arrangements of CCIs have different interaction dynamics with the grid. From the frequency-domain analysis, it is found that the distribution effect of CCIs can greatly affect the high-frequency (HF) behaviour of their output admittances, and consequently improves their interaction dynamics; hence, one of the factors which can also play an important role in HF behaviour is distribution effect of CCIs in a PV plant. The simulation studies of several distributed arrangements of CCIs as well as a centralised CCI confirm the validity of the performed analysis.