| Distribution system operating environments are changing rapidly. Proper distributed generation placement and operating will bring benefits for supporting voltage, reducing system loss, enhancing system reliability, releasing T&D capacity and improving energy management flexibility. Distributed generation will play an important role in distribution systems. However, with increasing number of distributed generators (DGs) installed within distribution systems, the traditional methods for distribution system modeling, analysis and planning needs to be revisited, and new tools are required to be developed.; This thesis addresses these challenges through slack bus modeling studies. First, traditional distribution power flow with a single slack bus model is revisited and a distributed slack bus model is proposed for distribution system analysis and planning. Network-based participation factors to distribute slack are developed. These participation factors capture network parameters, load distributions and generator capacities. Then, impacts on distribution operating and planning functions of slack bus modeling are investigated. Two examples, energy cost analysis and switch placement for DG islanding operation are discussed in detail. Last, the problem of distribution system expansion considering DG placement and feeder upgrade is addressed. |
