Power Losses and Bus Voltage in Transmission Lines of a 28 Bus System

Inadequate supply of power is increasing day by day and causing a lot of problems and affecting various sectors of the country. This work involves the power analysis on the 28-bus network of the Nigeria 330kV integrated power system. The network consists of twenty-eight (28) buses, nine (9) generation stations, and fifty-two (52) transmission lines. Newton-Raphson (N-R) method of power flow analysis was carried out on the network using the relevant data. This analysis was carried out using PSS®E to determine bus voltages, real and reactive power losses of the integrated network. The work also involves carrying out line outages on various parts of the network to determine the effects on power losses and bus voltages. The results show that the following buses were not in line with the statutory limit of 0.95≤Vi≤1.05: bus 13 (New-Heaven), bus 14 (Onitsha), bus 16 (Gombe), bus 19 (Jos), bus 22 (Kano). Bus 16 was observed to not satisfy the limit during the analysis going as low as 0.7602p.u. in one of the line outages (Makurdi-Mambila off). The total losses was also determined and the highest power loss was observed when Makurdi-Mambila line was taken out of service (142.54MW, 1072.16MVAR) and the lowest loss was observed when the double transmission line between Benin-Sapele were both taken out of service(105.0MW, 830.50MVAR). This result concludes that the Nigeria network still needs to undergo changes to ensure sustainable and reliable power system. Compensation is recommended on the above stated weak buses using Flexible Alternating Current Transmission System (FACTS).