Slack bus is a bus with generating unit and used to balance the real power (P) and reactive power (Q) in the power system while performing load flow studies. This study therefore, investigated the best slack bus suitable to be used in the load flow study of the Nigerian 330-kVtransmission network with nine (9) generating stations. The method involve the load flow analysis of the existing network with Egbin, Shiroro and Kanji generating stations chosen as a slack bus at different instances and simulated using Newton-Rapson method and Gauss Seidel. This study revealed that the use of Egbin power station as a slack bus brought about the lowest power mismatch in the network. The result also indicated violation of voltages in some of the network and high reactive power loss.
Keywords: Grid, Load flow, Matlab tool, Reactive power, Slack bus