Abstract
This paper uses adaptive particle swarm optimization (APSO) to reduce the power losses of radial and unbalanced three-phase distribution systems. A Matlab program is used to solve the three-phase IEEE 37-node test feeder using a backward/forward sweep (BFS) method. Two scenarios are adopted for adding a distribution generation (DG) at specified nodes. In the first scenario, the DG is assumed to generate only reactive power, while in the second scenario the DG generates both active and reactive power. The APSO algorithm determines the required amount of reactive and/or active power to minimize the total losses of the radial distribution system. At the meantime, adding the DG enhances the stability of the distribution system measured by its stability index.