Voltage Stability Assessment Using Modal Analysis

Abstract

Voltage instability incidence has of recent been a major threat to the optimum operation of a modern power system due to continuous increase in load demand and insufficient reactive power to meet the demand. Thus, it becomes imperative to carry out voltage stability assessment in a power system to prevent the catastrophe of voltage collapse. This work present voltage stability assessment using a technique based on modal analysis of the reduced Jacobian. The modal analysis method makes use of the power system Jacobian matrix to find the eigenvalues essential for the evaluation of the voltage stability of a power system. The bus with the smallest value of eigenvalue is taken as the critical mode of the system. The participation factor (PF) of each load node is then determined to evaluate the bus which contributes most to the critical mode identified. The bus with the highest value of PF is taken as the critical bus of the system. The effectiveness of the methodology presented is tested on the IEEE 30 bus power system. Result obtained shows that voltage stability assessment using modal analysis method could be of a great importance to power system operators in the identification of critical nodes that are liable to voltage collapse in power system.

Keywords: Power flow, modal analysis, power system, voltage stability, participation factor