Abstract: Renewable energy supply is environment friendly and promises a sustainable energy for future generation. However, connecting renewable energy resources to exiting power grid may cause technical issues which needs to be solved. The architecture of existing electricity power networks is based on large centralized power generations whereas renewable energy resources are relatively small, distributed and connected to the medium or lower voltage sides. Most renewable energy resources, e.g., PV systems, employ power electronic converters for power conditioning and interface with the grid. Further, renewable energy generation (e.g., from solar and wind) is intermittent in nature and hard to predict. These issues create a challenge for the integration of renewable energy sources into the grid as they can make power system operation and control more complicated and maintaining high quality of supply more difficult. Therefore, new power dispatching strategies and inverter control systems are essential in renewable power energy applications. A distribution network model has been developed in MATLAB/Simulink and implemented to evaluate the voltage profiles and power flow for different levels of PV systems. This will help in evaluating the impact of high penetration levels of small-scale grid connected PV systems on the power quality for a residential distributed network in the UK. Different penetration scenarious are variable load conditions are considered. The computer model developed has been validated by comparison with a reliable model that was developed using ERACS Software package. The result obtained confirmed that maintaining a stable operation and acceptable power quality in distribution networks are possible with a wide range of PV penetration levels.