Power generation from solar photovoltaics is rapidly increasing. In this scenario, this new technology has to work with the existing system in tandem to maintain stability during contingencies as it is a low inertia system. The interfacing power electronics devices have to be designed in such a way that the integration of the photovoltaic (PV) to the Grid is to be taken care during the disturbances. This paper presents the various issues when the PV penetration is comparable with the system capacity. The frequency of the system drops more in the PV-Grid connected system than the conventional generation system for same disturbance. Also, the frequency regulation methods get affected. The mode of operation of the inverter might be altered. An auxiliary source like batteries, ultra-capacitors is being suggested to balance the power for successful operation during abnormalities. In spite of this, many authors had developed new control techniques to mimic the interfacing inverter like conventional generating unit. The basic concepts of these methods have not explained in most of the literature. This paper reviews the concepts and applications of these methods and compares them.

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