Abstract: To further improve the penetration level and optimal layout of distributed generation （DG） in distribution network, the mathematical models of penetration level for a single power source and multiple power sources were established with the constraints of node voltage and line load flow, and the optimize layout model of DG was established with the target function of minimizing the active power loss. To effectively solve the models, an improved particle swarm optimization （IPSO） algorithm which combined PSO algorithm with quadratic interpolation was applied in an IEEE 33-node system. The optimal location and the optimal capacity of DG were simulated with the improved PSO, whose results were compared with that of PSO algorithm, and the power flow distribution under optimal layout was analyzed. The simulation results verify that the proposed method can effectively reduce the active power loss and improve the supply quality in distribution network after DG access.

Key words: distributed generation （DG）, particle swarm optimization （PSO） algorithm, penetration level, optimal layout, active power loss