Abstract Reliability and active power loss are two fundamental parameters in the design and planning of distribution systems that have always attracted the attention of power distribution systems designers and engineers. The improvement of reliability and the reduction of power loss are investigated as the primary objective functions and voltage profile as the secondary objective function. A method based on Krill Herd algorithm is adopted to optimize a single objective function that consists of a number of distinct objective functions and is made up of different weight coefficients in order to locate distributed generation units. Further, the results obtained from this algorithm will be compared to those of other methods. To evaluate the accuracy and efficiency of the proposed algorithm in finding optimal responses, standard grids including IEEE 33-bus and 69-bus radial distribution systems are employed. تفاصيل المقالة