Load model effect assessment on optimal distributed generation (DG) sizing and allocation using improved harmony search algorithm

The operation of a distribution system in the presence of distributed generation systems has some advantages and also challenges. Optimal sizing and siting of DG systems has economic, technical and environmental benefits in distribution systems. Improper selection of DG systems can reduce these advantages or even result in deterioration in the normal operation of the distribution system. DG allocation and capacity determination is a nonlinear optimization problem. The objective function of this problem is the minimization of the total loss of the distribution system. In this paper, the Improved Harmony Search (IHS) algorithm has been applied to the optimization problem. This algorithm has a suitable performance for this type of optimization problem. Active and reactive power demands of the distribution system loads are dependent on bus voltage. This paper verifies the effect of voltage dependent loads on system power characteristics. The load model has an inevitable impact on DG sizing and placement. The proposed algorithm implemented and tested on 69-bus distribution systems and the impact of voltage dependent load models are demonstrated. The obtained results show that the proposed algorithm has an acceptable performance.