Identification of voltage collapse vulnerable buses using modal analysis

This paper proposes the modal analysis as a method to identify the buses with the lowest voltage in the system. This modus operandi gives a measure for proximity to voltage collapse in the system buses. The modal analysis method computes the eigenvalues and eigenvectors of a reduced Jacobian matrix of the system. The computed eigenvalues determine the mode of voltage/ reactive power variation which provides a relative measure for voltage instability. In addition, the eigenvectors provide rich information about the network elements and generators that participate in each mode. The proposed method is fully indicative for weak buses when tested on the IEEE 30-bus as benchmark systems in addition to the Sudan National Grid.