The paper focuses on the impact grid-connected, largescale photovoltaic (PV) has on the power system operation (stability, availability, reliability) and protection philosophy. It assesses qualification methods and standards of particularly the utility-interactive equipment (grid inverters), which directly influences the security of supply and power quality of the grid. Advanced emulation of grid conditions, including hardware in the loop testing scenarios, are proposed for the testing and validation of such grid equipment under realistic conditions(including worst-case). This to ensure suitability of the equipment for grid application and stable and safe grid operation.