Voltage Quality Analysis on Power Transmission Networks: A Case Study of 330kV Power Transmission Networks in Nigeria

Abstract

The 330kV power transmission system in Nigeria is associated with numerous problems ranging from voltage instability, ageing network, long and weak transmission lines and insulators, absence of protection schemes on the distribution network, lack of spinning reserve to compensate for power shortages, obsolete substation equipment, and higher power losses which substantially affect the reliability of power supply in Nigeria. This study aimed at analysing this scenario and to propose stability improvement measures in the power Network. Voltage instability is a major factor responsible for several system collapse and blackout experienced in the country. This work used necessary data obtained from the National Control Centre (NCC) of Transmission Company of Nigeria (TCN) for load flow simulation with the help of MATLAB R2021a software. Newton-Raphson iterative technique was used to carry out the load flow analysis due to its ability to converge faster with less iteration than Gauss-seidel and fast decoupled iterative techniques. The simulation results revealed that buses 4 (Akangba), 5 (Jos), 7 (Ikeja-west), 10 (Alagbon), 19 (Damaturu), 23 (Sakette), 28 (Ajah), 33 (Oke-Aro), 34 (Ayede) and 42 (Lekki) violate the acceptable limits as its voltage magnitude falls below the standard limit of 0.95-1.05pu. It was also observed that buses 6 (Kaduna), 13 (Yola), 16 (Gombe), 22 (Kano) and 34 (Ayede) are close to the point of instability as their voltage magnitudes are between 0.95 and 0.96 pu. These buses need urgent compensation if stability improvement in the entire Nigerian transmission system is to be achieved.