ABSTRACT
This research work presents development of Firefly algorithm (FA) and application of voltage stability index (VSI) for optimal planning of Distribution Generation (DG) in an unbalanced threephase distribution network. The VSI was used to find the DG location while the FA was used for the DG sizing. The developed method was implemented on standard IEEE 37-bus Radial distribution network test system and a local 19-bus Mahuta feeder. The results obtained from the IEEE 37-bus were validated by comparing with a similar work. For the standard IEEE 37-bus unbalanced radial distribution network (URDN), the total power loss obtained are 31.3543 kW and 15.2829 kVAr for active and reactive power respectively without DG in the network. When the developed method is applied, a DG optimal location was found at bus 34 and a DG size of 356 kW and 170 kVAr for active and reactive respectively are obtained. The active and reactive power loss were found to be 19.8329 kW and 10.0014 kVAr respectively. The developed method recorded a loss reduction of 36.75% and 34.56% for both active and reactive power respectively over the base case. Also, the maximum loadability of the network was found to be 18% and 8% of the initial loading with and without DG respectively. For the 19-bus Mahuta feeder, the location for the DG is bus 17 and the DG size of 201.58 kW and 115 kVAr are obtained for active and reactive power respectively. A power loss reduction of 4.48% and 5.62% for active and reactive power were recorded over the base case respectively. The maximum loadability of the network for both the developed method and base case were found to be 119% of the initial loading. When compared with research on similar work, the developed method achieved a loss reduction of 8.14% and 30.42% for active and reactive power respectively over the method applied in the work.