The growing integration of Photo-Voltaic (PV) system in the conventional power system has become a matter of concern due to its significant impact on the power system inertia. High penetration of inertia less PV system will replace conventional rotating mass turbine-based generators and therefore lowers the entire power system inertia which results in a negative impact on specially frequency and transient stability performances of power system. In this paper an overview of the impact of high PV penetration on conventional power system inertia has been presented followed by a brief discussion on the technologies to mitigate the challenges.