Ignatius K. Okakwu^1,, Emmanuel A. Ogujor¹, Patrick A. Oriaifo¹

The Nigerian 330kV grid network is characterized with major problems like voltage instability (voltage profile violation), long transmission lines, nature of transmission lines and high power losses which affect power generation and distribution systems. This paper considered the load-flow study of the Nigerian 330-kV consisting of 32 buses, 11 generating stations and 36 transmission lines. Newton-Raphson iteration technique was used to carry out the analysis because of its fast convergence nature as compared to other iterative techniques. The data used for the study is obtained from Power Holding Company of Nigeria (PHCN). MATLAB/SIMULINK software was used to carry out the simulations. The results obtained shows that some of the bus voltages lie outside the prescribed limit of 0.95-1.05 pu (313.5 – 346.5kV). These buses include buses 16 (Kano 0.8721pu), 17(Kaduna, 0.9046pu), 18(Jos, 0.8580pu), 19(Gombe 0.8735pu) and 21(Katampe, 0.9167pu). The total active power loss is 268.622MW and that of reactive power loss is 2247.42Mvar. It is therefore inferred from the results obtained that the existing Nigerian 330-kV grid network is fraught with high line losses that require compensation using reactive power supports such as Flexible Alternating Current Transmission Systems (FACTS) devices, for effective line utilization.

load flow, Newton Raphson, losses, voltage, transmission line