Efficient methodology for stability analysis of synchronous machines

Abstract

The paper describes the fundamentals, analytical formulation and application of an efficient methodology for the transient and steady-state analysis of the synchronous machine. The state space phase co-ordinates model of the synchronous machine takes into account the time-varying nature of the machine inductances and inter-spatial harmonic inductances. The dynamics of the synchronous machine are represented by a set of ordinary differential equations (ODEs) in the time domain. The machine behaviour is analysed under severe abnormal operation conditions. The model allows a detailed and accurate transient representation of the machine, which cannot be achieved with conventional models based on the dq0 frame of reference, especially for the case of unbalanced fault analysis. The steady state after the fault is cleared up is obtained efficiently with the application of a Newton technique for the acceleration of the convergence of the state variables to the limit cycle. The synchronous machine model is compared in terms of accuracy and computational efficiency against a widely used and accepted machine model of an electro-magnetic transient program (EMTP-ATP).