The impact of increasing Penetration Level of Small Scale Distributed Generations on voltage in a secondary distribution network

This paper describes the impact on the voltage profiles of a secondary distribution network in the presence of Small Scale Distributed Generation (SSDG) units. The Penetration Levels of these SSDG units are varied and the effect on the voltage is simulated and analysed. The study also describes how the size of each SSDG unit affects the maximum penetration level of SSDG in the low voltage network while maintaining the voltage within statutory limits. The Case Study is a detailed model in DIgSILENT Power Factory® of a highly residential area with all network components modelled using manufacturer's data. Actual load profiles of consumers have been recorded and used for the simulation as well as recorded typical photovoltaic generation profile for Mauritius. The key contribution of this paper is the determination of the maximum amount of SSDG that secondary distribution networks can accommodate while maintaining the voltage within statutory limits. The results demonstrate that penetration level varies with the size of the installed SSDGs and for the different sizes simulated, the penetration level can be as low as below 10% for large SSDG (8.7 kW) and up to 60% for smaller size SSDG units (4.35 kW). No overloading of existing low voltage overhead cables has been observed in all the cases, even with reverse power flow.