Voltage stability assessment using the V-Q sensitivity and modal analyses methods

Voltage stability is an important factor, which needs to be taken into consideration in order to avoid voltage collapse. There are different methods used to study the voltage collapse phenomenon. In this paper, V-Q Sensitivity and Modal analyses methods are implemented on IEEE 14 bus system. Modal analysis method makes use the Jacobian matrix to determine the eigenvalues necessary to evaluate the voltage stability and V-Q Sensitivity method makes use of the diagonal elements of the inverse of reduced Jacobian matrix to a assess this stability. In this paper, our main objective is to apply V-Q Sensitivity and Modal analysis methods by analyzing the effect of neglecting the weak coupling between reactive power Q and voltage angle δ. A comparison in terms of the weakest buses is made between the results obtained by taking into account the weak coupling between Q and δ, i.e., by considering the reduced Jacobian matrix and those obtained by neglecting this coupling.