Voltage Stability Evaluation in the Nigeria 44 Bus Grid Network using Modal Analysis

This paper focused on the application of modal analysis method to determine the voltage stability of the Nigeria 44 bus 330kV transmission grid network and to determine the network’s weakest buses. Modal method calculates the smallest eigenvalue and all the associated eigenvectors of the reduced Jacobian matrix, JR using steady state mode. The network model was developed in PSAT-MATLAB and load flow was performed on the network. Results and analysis showed that the Nigeria 44 Bus grid network was found to be unstable as the modal analysis revealed the presence of eigenvalue with a negative real part. Gombe, Damaturu and Yola buses were also discovered to be the vulnerable buses since their voltage profile fell below the IEEE standard voltage level of (0.95-1.05) pu. Yola bus was spotted as the weakest bus based on the analysis of the participating factors.