Optimum placement and sizing of DG units based on improving voltage stability using multi-objective evolutionary algorithm

Abstract

This paper presents a method for locating and sizing Distributed Generation (DG) units based on the enhancement of voltage stability and network total loss reduction in radial distribution systems. In this method, a voltage stability index is used to determine the weakest buses from the voltage stability point of view as the best candidates for installing DGs. Also, an evolutionary algorithm based on Pareto Strength is used for solving the DG sizing problem. This problem is configured as a multi-objective optimization problem. The objective functions are defined as minimizing total power loss, enhancement of voltage stability and voltage profile improvement. Also, the effects of DG operating power factor and DG penetration level on total network loss and voltage stability are investigated and the DGs with the ability of generating reactive power are used. The selected DG penetration level is considered as a constraint in the evolutionary algorithm for determining the optimal size of DGs. It is shown that the selection of optimum DG penetration level can optimize the objective functions simultaneously. The proposed method is tested on a standard IEEE 69-bus radial distribution network. The obtained results are compared with similar previous methods and the appropriate performance of the proposed method is verified.