Analysis of asymmetrical faults in power systems using dynamic phasors

This paper presents application of the dynamic phasor modeling technique to unbalanced polyphase power systems. The proposed technique is a polyphase generalization of the dynamic phasor approach, and it is applicable to nonlinear power system models. In a steady-state, the dynamic phasors reduce to standard phasors from AC circuit theory. The technique produces results that are very close to those obtained from time-domain simulations. Simulations in terms of dynamic phasors typically allow larger integration steps than the standard time-domain formulation. We present simulations of unbalanced faults involving a three-phase synchronous generator connected to an infinite bus through a transmission line, and we demonstrate that models based on dynamic phasors provide very accurate descriptions of observed transients.