Influences of Power Electronic Converters on Voltage-Current Behaviors During Faults in DGUs-Part II: Photovoltaic Systems

Photovoltaic (PV) systems have become a popular type of distributed generation units (DGUs) for small and medium levels of renewable energy generation. When grid connected, these DGUs are designed and operated to deliver electric power to their host grid through power electronic converters. The nonlinear and switched natures, along with the control actions, of these PECs can influence the voltage-current behaviors during faults in grid-connected PV systems. This paper experimentally investigates the voltage-current behaviors during faults occurring in grid-connected PV systems. Results of these investigation show that voltages and currents at the point-of-common-coupling (PCC) experience changes in their magnitudes and harmonic distortions due to faults occurring on both sides of PCC. These results can be incorporated in the improvement of the accuracy and reliability of protective devices used for grid-connected PV systems.