Increasing concern on pollution and global warming has prompted Photovoltaic (PV) system as one of the potential renewable and clean energy in power system generation. Power quality issue such as Total Harmonic Distortion (THD) has become an increasingly serious concern as more PV is integrated into the grid system. This encourages an extensive study to identify the challenge in power system network. In this paper, the impact of solar irradiance to current and voltage THD is studied using the simulation model developed in Simulink. This model is very useful to help the power system engineers and researcher to study the electrical behavior of the PV system. The PV model developed is tested by using the real solar irradiance data taken from UTeM laboratory, and were experimentally tested to validate the model. The results show that the developed PV model is able to predict the PV system behavior, particularly on THD.