ENHANCING THE TOPOLOGICALLY WEAK TRANSMISSION LINE LOSSES USING TAP-CHANGING TRANSFORMERS: NIGERIA TRANSMISSION NETWORK SYSTEM, A CASE STUDY.
OGUNDARE, A. B.,ADEJUMOBI, I.A.,OMOGOYE, S. O.,OGUNYEMI J., GBOTOSO, G.A., and OYETOLA J.B.
ETRJ. Vol. 8(2), 30 March, 2023
160 Download(s) 131 View(s)
Abstract: Power system network expansion requires operational and infrastructural planning through accurate determination of the operating points of the system. An acceptable power system operation is one in which no transmission line is overloaded and all bus voltages are within the statutory limit. The Nigerian power system network is known to be experiencing uneven distribution of the generated power. This has led to long transmission lines topology uneven voltage profile and as well as high power loss. In this study, Nigerian 30-bus, 330 kV rating grid systems are analysed using Neplan software. The power transfer distribution factor index (PTDFI) was used as an optimization tool to determine the weak transmission lines. The lines which have their PTDFI greater or equal to unity are the weak transmission lines. The power flow results show that six transmission lines are topologically weak while five transmission lines are overloaded and the total active power loss of 19.08 MW was simulated. The weak transmission lines are Calabar-Okpai, Kano-Kaduna, Kaduna-Jos, Onitsha-Benin and Onitsha-Newhaven. The network was expanded by adding a transmission line in parallel to each of the five identified overloaded transmission lines to reduce the reactance. Also, the network was further modified by connecting a tap-changing transformer on each of the six identified weak transmission lines to reduce the voltage drop. The results of the modified network indicate that all the bus-bar voltages as well as the transmission lines are within the specified limits and the real power loss dropped from 219.08 MW to 112.81 MW for the initial network and expanded network respectively.
