Voltage Stability Assessment Using Equivalent Nodal Analysis

This paper presents a simple method for voltage stability assessment by reducing the bus impedance matrix of a network into its two-bus equivalent model at a referred bus. Closed-form equations of the equivalent model could then be derived to facilitate an equivalent nodal analysis at the referred bus to determine its voltage stability limit. The method was also shown to have parallels with the well-accepted modal analysis of the Jacobian matrix. These include defining geometric indices to identify critical buses and participation factors to quantify contribution of network elements to their criticality. The method however does not require post power flow solution processing of the Jacobian matrix; such computational advantage may make it suitable for online applications. The IEEE 300-bus system was tested with the method which was shown to be valid and computationally robust and efficient.