Second and Higher-Order Diagonal Padé Methods: Accuracy and Applicability for Stability Studies of Large Power Systems

The paper evaluates the accuracy of the second and higher-order diagonal Padé methods of numerical integration and their applicability for stability studies of large power systems. The accuracy analysis is based on characteristics of damping and frequency distortions of free motion modes for a linear dynamical system. The Padé-(2,2) method, which is in the focus of attention, despite its higher accuracy in comparison to the Padé-(1,1) method (trapezoidal) and despite not being prone to numerical oscillations, does not seem to be applicable for large power systems. Unless the eigenvalue loci of their models in the complex plane change qualitatively and the efficiency of implementation is dramatically enhanced, it is highly unlikely that the Padé-(2,2) method can be competitive. This conclusion applies even more to the higher-order diagonal Padé methods.