A Renewable Energy Source (RES), enhanced with Fault Ride Through (FRT) capability, can provide proper voltage and frequency support to the power grid under several disturbances. This paper investigates how a realistic dynamic power system with high penetration of RES reacts under different operating conditions. More specifically, the power system operation when RES operates according to the current grid regulations of the Cyprus TSO is demonstrated. For the purposes of this investigation, a RES is interconnected with the IEEE 9-bus test system, reinforced with an appropriate directional over-current protection scheme, and dynamic electromagnetic transient simulation results are provided.