Effect of PV power injection in unbalanced distribution systems

Photovoltaic (PV) power is a favorable source of clean energy, which can be easily integrated into distribution systems, next to loads. However, to meet a considerable load portion of the system a high penetration level of PV is required. This high penetration level along with unbalanced connection of single phase rooftop PV units makes it necessary to assess the effect of PV on the voltage of unbalanced distribution systems. Considering the complexity of analyzing unbalanced systems, this paper develops a practical method based on load flow formulation. In this method, two sets of scalar matrices are derived to estimate the effect of PV real and reactive power injections on power system voltage profile. Comparison between actual and estimated results for IEEE 37-bus test system verifies the effectiveness of proposed estimation method.