Optimal placement and sizing of Distributed Generation (DG) are essential for future power planning of distribution networks. The performance of Gravitational Search Algorithm (GSA) and an Improved version of Gravitational Search Algorithm (IGSA) are compared in solving the optimization problem. The multi-objective function optimization includes power loss minimization (P_loss), Minimum bus voltage (Vbus_min), and an average voltage total harmonic distortion (THDv) are considered in this optimization problem and the IEEE 13-bus and IEEE 69-bus radial distribution network were applied on this study. The benefits due to the optimal placement and sizing of DG include power loss reduction, minimization of total harmonic distortion, and improvement of bus voltages, especially the weakest bus in the distribution network. The impact of DG installation at the proposed location with the proposed sizing on voltage stability margin also presented. The results show the Voltage Stability Margin (VSM) for both real power (P) and reactive power (Q) at the weakest bus after DG have improvement with present of DG.

分布式发电 (DG) 的最佳布局和规模对未来配电网络的电力规划至关重要。比较了引力搜索算法（GSA）和改进版引力搜索算法（IGSA）在求解优化问题时的性能。多目标函数优化包括功率损耗最小化 (P _loss )、最小总线电压 (Vbus _min) 和平均电压总谐波失真 (THDv) 被考虑在这个优化问题中，并且 IEEE 13 总线和 IEEE 69 总线径向配电网络被应用于这项研究。DG 的最佳布置和尺寸调整带来的好处包括减少功率损耗、最大限度地减少总谐波失真以及改善母线电压，尤其是配电网络中最弱的母线。还介绍了在建议位置安装 DG 和建议尺寸对电压稳定裕度的影响。结果表明，随着 DG 的存在，DG 得到改善后，最弱母线上的有功功率 (P) 和无功功率 (Q) 的电压稳定裕度 (VSM)。