This paper proposes a decentralized control strategy for higher penetration of photovoltaic (PV) units without violating system operating constraints. A systematic procedure is developed and a robust controller is designed to ensure both dynamic voltage and transient stability for a specific PV integration level. The change in the model due to the volatile nature of PV generations is considered as an uncertain term in the design algorithm. Simultaneous output-feedback linear quadratic controllers are designed for PV generators. This designed control scheme is robust with respect to intermittency and enhances the integration level in a sub-transmission and distributed system. The effectiveness of the proposed controller is verified on a 43-bus industrial meshed distribution system under large disturbances. It is found that the designed control scheme enhances stability and increases the renewable integration levels.