Abstract

This paper proposes a method for the choice of the injection node of an incoming power plant into an existing grid. The southern interconnected grid (SIG) of Cameroon is used as an example to demonstrate the advantages of using the proposed methodology. Given that the minimization of transmission losses constitutes a major cost-saving factor in electricity delivery, this work starts with the hypothesis that, if a power injection busbar is chosen within the existing grid such that the overall transmission losses are kept at a minimum, then it will be close to the load center, it will take care of the capability of the existing network to accommodate the new power injection, it will lead to increased reliability of power supply to several loads by providing for alternative supply routes, as well as result in a good voltage profile in the entire network. This paper therefore presents an approach for the determination of the power injection node of the lastly commissioned 216-MW Kribi natural gas thermal plant in Cameroon, based on the minimization of the overall network power losses. A Newton-Raphson load-flow solution with 34 busbars for the SIG of Cameroon is first developed in MATLAB, the overall network losses computed for successive injection into each of the existing network nodes, and the power injection busbar for the newly constructed 216-MW Kribi natural gas power plant determined based on the aforementioned criterium. It is observed that the injection node is close to the densely populated industrial city of Douala and the 384-MW reference hydropower plant of Songloulou can run with its full capacity. A comparison with the current interconnection busbar at Mangombe reveals that the cheaper hydro-generation of Songloulou must be reduced by about 76 MW to accommodate the more expensive incoming 216 MW from Kribi in the grid, and the overall network losses are increased by 73 MW. This explains why the Dibamba 84-MW thermal plant in proximity to the current inje