Grid integration of renewable energy system has the advantage of more effective utilization of generated power. However, the technical requirements from both grid and PV sides need to be satisfied to ensure the safety of the installer and the relaibility of the utility grid. This project is mainly aimed to investigate on the power quality issues results when wind and PV systems are interconnected to the utility grid. Major power quality issues such as harmonic distortion, voltage disturbances and asymmetry are considered.