Transient performance of doubly excited synchronous machine

The paper describes an investigation of the transient behaviour of a doubly excited synchronous machine, both with and without excitation controls. The analysis shows how the positional change of the resultant rotor m.m.f., due to the induced currents, gives an inherent advantage to the doubly excited machine over a conventional synchronous machine, for the improvement of transient stability. When excitation controls are employed, there is a further improvement in the transient-stability limit, with a greater contribution coming from the voltage regulator.