Using AC optimal power flow for DG planning and optimisation

While it is difficult to estimate how much distributed generation (DG) capacity will be connected to distribution systems in the coming years, it is certain that increasing penetration levels require robust tools that help assess the capabilities and requirements of the networks in order to produce the best planning strategies. This work presents an overview of some of the uses to which a tailored AC Optimal Power Flow (OPF) can be applied to DG planning and optimisation. Its application to maximising connectable capacity and energy loss minimisation are presented and discussed. The incorporation of a wide range of network constraints, including fault levels, voltage step change and N-1 security are also outlined. The AC OPF technique is extended to a multi-period approach to cater for the variability of demand and renewable generation. Advanced smart grid-like control strategies are also incorporated into this planning tool in order to evaluate the potential benefits. Simple test feeders as well as generic UK distribution systems are adopted to demonstrate the methodology.