Abstract The paper develops a comprehensive model for optimal allocation and sizing of DG units using the Dingo Optimization Algorithm (DOA) targeting active power loss reduction with a concomitant improvement in voltage stability across both distribution (DN) and transmission networks (TN). The novel methodology evaluates the effectiveness of operation of renewable DG units under two different network structures. In the IEEE 33-node DN, DG units comprising PV are optimally placed, with consideration for a constant amount of reactive compensation, considering the practical limitations of the used inverters. In the IEEE 118-node TN, which is a more complicated, meshed grid, PV alone, as well as hybrid configurations combining both PV and Wind technologies, operating at an optimal power factor of 0.95 are considered. In addition, a dispatch factor of 0.3 is applied for hybrid systems under light load to mitigate the high penetration of the renewable energy DG units. Results from the evaluation of IEEE 33-bus network indicate the effectiveness of DOA in securing substantial reductions in active power losses at percentages of 81.63%, 48.37%, and 79.45% in cases of normal, light, and heavy loadings, respectively, coupled with marked improvement in the voltage stability level of the power grid. For instance, during regular operations, the lowest Voltage Stability Index (VSI) rose from a critical point of 0.695 to a safe point of 0.898, whereas the highest Voltage Deviation Index (VDI) fell from 0.087 to 0.027. Application of the algorithm to the 118-bus TN indicates that placing three PV DG units optimally results in reductions in active power losses by 16.98%, 8.39%, and 16.24% in normal, light, and heavy loadings, respectively. Incorporating a hybrid system involving three PV units and three wind power DG units reduces the active power losses to 18.07% in the case of normal loading and 23.98% for heavy loading. Finally, deployment of the dispatch factor achieves a positive reduction in power losses of 12.61% in the light load scenario. Additionally, network stability improved in the hybrid topology when the network was under high traffic loads, leading to the minimum Voltage Deviation Index (VDI) being reduced from 0.1015 to 0.0863, while the maximum Fast Voltage Stability Index (FVSI) was 0.2817.
Kotb et al. (2026) studied this question.