Recently, the applications of solar energy to generate electric power using photovoltaic, PV is increasing rapidly, to improve the utilization of this system a power electronic converters are needed, whoever these power electronic devices inject harmonic current into the grid consequently deteriorate the quality of electric power. This paper studies the effect of PV system location and PV penetration level on the harmonic content at the point of common coupling and on the other power grid buses. The study will be conducted by integrated different rating of PV system with the nine-bus IEEE system at different location to determine the best location and penetration level in order to minimize the total harmonic distortion. The system modelling and simulations are carried out using MATLAB platform