Fault Analysis of South Eastern Nigerian Power System Network

Fault analysis is imperative in the study of power system networks as this helps to ensure that there is a stable supply of electricity in the system and ensure an even operation of the power system. In this paper, the South Eastern Nigeria network is being considered. Different categories of faults: symmetrical and unbalanced (Shunt and simultaneous) faults were considered at four (4) different bus locations: Alaoji 330 kV, Onitsha 330 kV, Alaoji TS 132 kV and Egbu Transmission 132 kV buses. The analysis was done using standards IEC 60909 and IEC 61363 for fault analysis. The results showed that for a symmetrical fault on Alaoji 330 kV and Onitsha 330 kV buses, the respective fault currents at Alaoji 330 kV bus are higher than that which occurs at Onitsha 330 kV bus. Results also showed that it took a longer time to reach steady state current values when a fault occurred at Alaoji 330 kV bus than at Onitsha 330 kV. Furthermore, the results showed that during unsymmetrical fault conditions- shunt and simultaneous faults, there was a spike in the rated line voltage on non-faulted lines at Egbu transmission by as much as 131% while there is a decrease in the rated line voltage at Alaoji 132 kV for the non-faulted lines by as much as 79.8%. Conclusively, a proper understanding of the South East Nigeria fault analysis is necessary for adequate protection and stability study.