Investigating the Impacts of Distributed Generation on Transmission Expansion Cost: An Australian Case Study

Distributed generation (DG) is rapidly increasing its penetration level in Australia, and is expected to play a more important role in the power industry. An important benefit of DG is its ability to defer transmission investments. In this paper, a simulation model is implemented to conduct quantitative analysis on the effect of DG on transmission investment deferral. The transmission expansion model is formulated as a multi-objective optimization problem with comprehensive technical constraints, such as AC power flow and system security. The model is then applied to study the Queensland electricity market in Australia. Simulation results show that, DG does show the ability to reduce transmission investments. This ability however is greatly influenced by a number of factors, such as the locations of DG, the network topology, and the power system technical constraints.