Impact of unbalanced grid conditions on PV systems

With more and more photovoltaic (PV) panels, energy storage devices and other small generators being put into service, it is necessary to integrate them into power systems. Grid integration provides a reliable means for customers to use renewable energy such as solar at its maximum and to use other sources as backup. Inverters are widely used as interfaces for these distribution resources. In this paper, impact of unbalance on grid connected PV panels will be first investigated. Then detailed models of PV systems with inverter interfaces and control structures are formulated and built in PSCAD, a commercial software package for digital simulation. Computer simulations will be followed to verify the analysis. Further, countermeasures will be sought to mitigate the impact.