Evacuation of power from distributed generation plants using optimal placement of Autoreclosers.
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Several factors affect the adequate evacuation of power from distributed generation plants in Uganda. Power evacuation is a critical function that allows generated power to be immediately transmitted from the generation plant to the grid for further transmission and distribution. The unreliability of the main dispatch feeder, as well as the manual operation of the distribution network, were cited as key issues that affect fast supply restoration in event of a fault in the network. Kabalega mini hydropower plant in Buseruka sub-county, Hoima district, was chosen as a case study because of its history of poor performance in terms of very long outage hours. The study objectives were to develop a power system model for the distribution network evacuating power from the case study and evaluating its technical performance, optimally place remote-controlled switches on the network model to assess the distribution network’s reliability and evaluate the economic viability of the proposed smart grid interventions. In the study, two cases were considered: one case before and another after the commissioning of the high voltage transmission line from Hoima to Nkenda Substation. Technical data reports were obtained from the utility and used in DigSILENT Power factory 15 to model the plant’s network. The data was exported to MATLAB R2015a where a genetic algorithm run a search on the entire radial distribution network and determined the optimal number and location of remote-controlled switches (RCSs). The RCSs considered were autoreclosers. Simulation was done for both the base case (with no switches) and the optimized network obtained after the RCSs had been placed. The system average interruption duration index (SAIDI), cost of energy not served (CENS), and total system cost were then computed. In case 1, distribution automation resulted in a loss reduction of 19.1 %, whereas in case 2, switches placed at appropriate locations resulted in a loss reduction of 14 %. This resulted in yearly energy savings of 1.431 GWh and 0.933 GWh in cases 1 and 2, respectively. The voltage profiles also improved significantly, with the lowest voltage drop in case 1 being 0.93 p. u and the lowest voltage drop in case 2 being 0.98 p.u. The economic analysis gave a cost benefit ratio, payback period and annual savings of 1.95, 1.05 years and Shs 113,936,568 respectively for case 1. Similarly, for case 2, the cost benefit ratio, payback period and annual savings were 1.17, 5.89 years and Shs 33,936,568 respectively. This meant that not only was optimum remote- controlled switch placement technically feasible, but it was also financially feasible.