Optimizing the size and location of distributed generators to maximize the grid stability

Distributed Generators (DGs) are being increasingly utilized in power system distribution networks to provide electric power at or near load centers. These are generally based on technologies like solar, wind and biomass and range from 10 kW to 50 MW. Research work carried out in this thesis relates to the optimal siting and sizing of DGs in order to maximize the system voltage stability and improve voltage profile. This has been formulated as an optimization problem and solved using LINGO software. Power flow equations have been embedded in the LINGO formulation, along with other operating constraints. The solution provides optimal values of the bus voltage magnitudes and angles, which have been utilized to compute a stability index. Finally, a multi-objective formulation has been developed to simultaneously optimize the size and placement of the DGs. The impact of the DGs on voltage stability and voltage profile has been studied on IEEE standard distribution test systems and verified using 'three-phase unbalanced power flow software' developed at Mississippi State University (MSU). Results indicate that the sizing and siting of DGs are system dependent and should be optimally selected before installing the distributed generators in the system.